DIY reflow oven - suitable UK/EU candidates

[Lomax]

So I've come to a point where I need to add a small oven to my workshop - not only to use for soldering my own boards, but also for reflowing laptop motherboards (and graphics cards) which has become a surprisingly common need (I blame lead-free solder & programmed obsolescence!) - and for various other heating related tasks (paint baking, drying silica gel, vacuum forming, melting/heating various materials, etc, etc, etc). I'm not initially planning to replace the controller, but to use an external thermometer with a thermocouple and manually controlling the process, though later on some kind of Arduino based controller will replace the original controls. Having looked at a myriad of "mini" and "toaster" type ovens I've come up with a list of criteria which any candidate oven ideally should meet:

• High power/volume ratio
• Non-coated interior (or at least, non-Teflon; ceramic coating is ok)
• Double glass door (for better heat retention)
• Quartz heating elements (for lower inertia)
• Multiple heating elements (at least two above and two below)
• Fan assist ("convection", for more even heat)
• Stainless exterior with few plastic parts (to handle higher temperatures)
• Wide enough interior to handle most laptop motherboards (min 30x25cm)
• Tall enough interior to handle 3D objects (up to 10-15cm height)
• Decent insulation (faster/hotter, and lower clearance requirement)
• Good looks (yes, this is important to me!)
• Smallest possible external dimensions (my workshop is tiny!)
• Low cost (ideally no more than £50)
• Available in a 240V model, and on the European market

And here's my list of candidates:

Model

Volume

External

Internal

Power

Type

U/B

Fan

Price

Glass

Inside

Outside

Dualit DMO1

14L

45x33x25

30x26x18

1.5kW

Metal

2/2

Yes

n/a

Double

Coated

Stainless, some plastic

Dualit 89200

18L

42x36x25

30x25x17

1.3kW

Metal

2/2

Yes

£100

Double

Alu

Stainless, some plastic

Abode AMO1801

18L

43x35x23

32x28x19

1.3kW

Metal

2/2

Yes

£50

Double

Alu

Painted, much plastic

Steba KB11

9L

36x29x22

25x23x14

1.0kW

Quartz

1/1

No

£60

Double

Alu

Painted, much plastic

Steba KB14

14L

40x35x25

27x26x19

1.2kW

Metal

2/2

Yes

£70

Double

Coated

Painted, some plastic

Steba KB19

19L

43x36x26

30x28x22

1.3kW

Metal

2/2

Yes

£100

Double

Coated

Stainless, some plastic

Brandt FC160MW

16L

45x37x32

1.4kW

Yes

£80

Double

Coated

Painted, much plastic

Brandt FC215MW

21L

46x37x29

1.4kW

Yes

£100

Double

Coated

Painted, much plastic

Moulinex OX110E30

9L

0.5kW

Quartz

No

Coated

Painted, much plastic

Moulinex UNO OX130230

15L

43x36x31

1.3kW

No

£70

Double

Coated

Painted, much plastic

Ariete Bon Cuisine 210

21L

45x33x23

32x

1.5kW

Quartz

2/2

No

Bon Cuisine 210 Metal

21L

44x33x26

32x25x20

1.3kW

Metal

2/2

Yes

Double

Alu

Stainless, little plastic

Lakeland Mini Oven

18L

42x37x26

?

1.3kW

?

?

Yes

n/a

Double

Alu

Stainless, some plastic

Efbe-Schott SC MBO1000

13L

46x36x21

32x30x11

1.4kW

Metal

2/2

No

£50

Double

Steel

Painted, much plastic

Dema 1500W pizzaofen

18L

46x42x20

34x34x6

1.5kW

Metal

4/4

No

£75

Double

Steel

Stainless, some plastic

Roller Grill FC 260

26L

47x48x28

33x30x23

1.5kW

Metal

Loop

Yes

£400

Double

Stainless

Stainless, little plastic

I've had great difficulty finding any small ovens with quartz type heating elements, though it may be possible to replace the metal bar heaters in some models. The Roller Grill model is only on the list because I liked the way it looks - at £400 it's far outside my budget, and it is also a little bit too large. The Dualit oven is similarly designed, with very little plastic and no painted surfaces, and a much better size, but the current model has been getting terrible reviews and costs too much! The most solid and best looking of the others is the Steba KB14, which has plenty of insulation and few plastic parts, but this is also a bit pricey and maybe not quite large enough on the inside to handle laptop motherboards. It also has some kind of coating on the inside, but I do not know if this is a Teflon or ceramic type. The Abode oven has the best internal dimensions, and also ticks most other boxes, but it has a painted exterior with lots of plastic parts and looks kinda ugly. Comparing internal/external dimensions it is clear that it also has little insulation. The Dema pizza oven is an interesting option, with a stainless catering style exterior and shaped heating elements that cover a large area. The internal height of only 6cm makes it useless for a lot of things though, and I worry that the short distance between elements and PCB will make heating very uneven (despite the larger heating elements).

Edit: I've updated the table above with additional models.

To make a long story short: I'm stuck and unable to decide which oven to go for! What to do? The only thing I could think of was to post here and ask for some input, which may tip the balance in favour of one of them Here are a few photos (because a picture is worth a thousand words):

[Owen]

Steba KB11

11L

36x29x22

25x23x14

1.0kW

Quartz

1/1

No

£60

Double

Alu

Painted, much plastic

I'm using the Steba KB11 as reflow oven in combination with a reflow controller. It ramps up round about 1°C/sec. The thermal switch is a bit annoying on multiple runs because you have to let it cool down quite a bit or it will stop heating while ramping up. Btw your Volume is wrong it 8 L (so 125 W/L). But i have to admit that i'm only using this oven to reflow my own PCBs and not for repairing motherboards.

hope this helps.

[Lomax]

I'm using the Steba KB11 as reflow oven in combination with a reflow controller. It ramps up round about 1°C/sec. The thermal switch is a bit annoying on multiple runs because you have to let it cool down quite a bit or it will stop heating while ramping up. Btw your Volume is wrong it 8 L (so 125 W/L). But i have to admit that i'm only using this oven to reflow my own PCBs and not for repairing motherboards.

Many thanks Owen, interesting to hear about the KB11 - I included it as I thought it looked really good and I love the small size! It's also the only one on my list that uses quartz heating elements. And thanks for the volume correction - I'll update my table to reflect this. If the only reason for getting an oven was to do my own boards, then it would be my model of choice, but for other uses it's just a little bit too small. I also worry that even if a given laptop MB would fit (and many probably would) the absence of a fan and the single elements might mean that to reach reflow temperature on the problem chip (usually the GPU) other areas of the board might be overheating.

That said, I suppose MB repair could be done with a hot-air-gun instead - but then a quality hot air gun is what I should get, and I couldn't use that for any of the other things that an oven could be used for. I've been over these lines of reasoning many many times and keep coming back to how useful it would be to have an oven with a ~30cm internal width, and tall enough to take a cup or painted object (~10cm). I also already have a Weller hot-air pencil, and a Portasol gas pen, which do most of the things I need hot air for - though neither will reflow a large chip reliably.

P.S. If you're having trouble with the thermal switch, why not just bypass it?

[Lomax]

Can anyone help fill in the missing info on the Lakeland Mini Oven? These are available refurbished for ~£60 and may be a great candidate; I suspect they are made by the same people who make the Breville BOV800XL Smart Oven which has received rave reviews, particularly for providing very even heat (but is only available for the US market and 120V). I think the Breville has quartz heating elements, so maybe the Lakeland does as well? They do look quite similar - see photos.

Edit: I note with envy, and not for the first time, that the options available to US customers far surpass what can be found on the British market...

[Lomax]

I think I might have found a candidate which uses quartz elements, and four of them (2/2) as well, for a rated total of 1.5kW. It's a little big though, at 20L, and 5cm wider than the Steba KB 14 (my current #1 choice) - and it doesn't have a convection fan. The question is: just how desirable is it to have quartz elements? This oven can supposedly reach 230 degrees in just 3.5 mins (~1 degree/sec), which sounds quite fast for such a large oven.

Is it worth trading off on convection, insulation and size just to get quartz elements? Or is having a fan more important? I really have no idea!

[DerekG]

and it doesn't have a convection fan

You have to be careful with fans as I have found that they can move the small SMD components around.

[Lomax]

You have to be careful with fans as I have found that they can move the small SMD components around.

Thanks Derek, that's a good point! Though I guess that I can disable the fan for all or part of the cycle if this becomes a problem. I've seen it mentioned in several places that having a convection fan is a good way to avoid hot spots, which if you're going to reflow large/expensive/irreplaceable boards (like laptop MBs, or graphics cards) may be a big problem. I would have thought the fan would need to be quite powerful to shift components, but then maybe they are - I've never used one of these little ovens so I don't know. Maybe it's not the airflow that causes problems, but vibrations from the fan motor? If so, I suspect this can be improved by dampening the fan motor mount.

What about the inside coating some of the ovens have? I'm not keen on this and would prefer not having any, but I have no idea if it's likely to cause any problems. I know Teflon can produce toxic gas if heated to too high a temperature, which considering I'll be messing about with the temperature control might well happen...

[Fred27]

I'll be interested to see what you go for and how well it works. When I was looking I found there was hardly anything available in the UK.

I ended up going for something 9L and very cheap from Robert Dyas. Not great but works well enough for my small boards. Even with some welding blanket insulation it gets too hot to want the controller (and cold junction compensation) inside the oven enclosure.

[Neganur]

Don't forget the Severin series, e.g. TO 2034: https://www.beta-estore.com/rkuk/order_product_details.html?wg=1&p=16

Fairly affordable.

[Codemonkey]

I bought one from Currys a while back. At the time it was the cheapest one they did (£24.99) and was branded as LOGIK (their own brand). It looks exactly like the Abode one you listed except the middle knob doesn't have the fan selection as mine doesn't have a fan.

I built my own PID controller which has a 13A socket on it, and just feed the thermocouple in through a small gap in the front door. To use it, I select the stay on option on the bottom knob, turn the top knob to max, and select both top & bottom elements on the middle knob, then plug it into my controller and off I go!

It doesn't seem to have any problems following the profile for lead free solder I programmed into it apart from the cooldown phase where I have to open the door.

[DerekG]

I guess that I can disable the fan for all or part of the cycle if this becomes a problem.

You can reduce the fan speed to approx half speed by just adding in a 1N4004 diode in series (if it is a 240Vac fan that is).

Small components like 0603 etc are the ones that get pushed around if the fan is too strong.

I've seen it mentioned in several places that having a convection fan is a good way to avoid hot spots

A lot of this depends on how much heating is actually being done by infrared. The fan helps with convection, but not direct infrared.

You will find by experimentation which way to place your boards in the oven to avoid the larger components "shadowing out the infrared heat" from the smaller components.

[mikeselectricstuff]

You can reduce the fan speed to approx half speed by just adding in a 1N4004 diode in series (if it is a 240Vac fan that is).

Depends on the type of fan. I've not taken apart a convection oven but small fans tend to be shaded-pole motors, which can't be speed-controlled like this. You'd probably be better off controlling  it by blocking part of the airflow.

[Lomax]

I'll be interested to see what you go for and how well it works. When I was looking I found there was hardly anything available in the UK. I ended up going for something 9L and very cheap from Robert Dyas.

I was in my local Robert Dyas a few days ago, specifically to look at mini ovens, but they only had two models and one of them had hobs on top (I don't want this). You're right that the options available in the UK are quite limited, but I've looked in France and Germany as well, where you can find many models not available here - often with surprisingly low shipping costs (e.g. I can get the Steba KB 14 from France for £75 including shipping, while it's £90 on Amazon UK)

Don't forget the Severin series, e.g. TO 2034: https://www.beta-estore.com/rkuk/order_product_details.html?wg=1&p=16

I did look at Severin after seeing the EEVblog videos about the reflow kit from Beta Layout, which is based on the Severin TO 2034. This oven doesn't have a fan though, and it's a little big (20L), and it has a painted exterior with a lot of plastic. In my mind an Arduino controlled oven can be useful for many things - not only reflowing PCBs - some of which may require much higher temperatures than it was designed for. For this reason I'd prefer an oven that has a stainless exterior with few plastic parts, and a plain aluminium or steel interior that isn't coated (or has a ceramic coating). It may be an ambitious goal but it is my plan to buy preciesly one device to serve as "that box I can put stuff into to heat it up real good". For this reason I am now leaning towards the Dualit or Lakeland ovens (see below).

I bought one from Currys a while back. At the time it was the cheapest one they did (£24.99) and was branded as LOGIK (their own brand). It looks exactly like the Abode one you listed except the middle knob doesn't have the fan selection as mine doesn't have a fan.

Yeah, I've seen that one, and it is indeed very similar! As with so many things these days, doing product research is greatly complicated by the fact that no-one makes anything any more; the label on the product bears no relation to where and by whom it was made. There's probably an entire city in China somewhere which only does mini ovens, with whole families spending their entire lives inside in a giant factory/labour camp churning out flimsy junk that is then stamped with Brand X for consumption by gullible westerners. Bosch, Black & Decker, Severin, Steba, Dualit, Breville - they are only brands today and the actual manufacturer is probably the same anonymous state-owned sweatshop.

It doesn't seem to have any problems following the profile for lead free solder I programmed into it apart from the cooldown phase where I have to open the door.

When I get round to replacing the controls on my oven I'll look at including a mechanism that can open the door programatically - I reckon a linear actuator (not a solenoid!) like this one should be able to push open the top of the door wide enough for cool-down without disturbing the soldered board(s).

A lot of this depends on how much heating is actually being done by infrared. The fan helps with convection, but not direct infrared. You will find by experimentation which way to place your boards in the oven to avoid the larger components "shadowing out the infrared heat" from the smaller components.

That makes perfect sense, good point! I guess this explains why it's so hard to find a convection oven with quartz elemets, which (I think) produce more radiated heat than the metal type elements?

Depends on the type of fan. I've not taken apart a convection oven but small fans tend to be shaded-pole motors, which can't be speed-controlled like this. You'd probably be better off controlling  it by blocking part of the airflow.

To be honest I'm not that worried about the fan; I know I would prefer an oven that has one, but should it turn out to cause problems I can probably modify it somehow to fix this - or in worst case not use it at all during the reflow phase. A fan will be useful during the other stages, as well as for many other things (e.g. for drying silica gel pouches, which I have and use tons of!).

Thanks everyone for your interesting and helpful replies - I am now leaning towards the Lakeland Mini Oven, for the following reasons:

• Stainless steel exterior (well, mostly)
• Aluminium coated steel interior
• Fan assisted with two wide fan openings top and bottom (from photos)
• Large enough for laptop MBs (based on exterior dimensions - I don't know the internal dimensions)
• Internal light (though this could be retrofitted, having one already is nice)
• Flat-ish front panel for easy modding
• Replacing the controller would yield 2x rotary encoders and other nice bits
• Substantial looking externally removable drip tray (for failed experiments!)
• At £65 delivered it's close enough to my target price of £50

What do you guys think? Would you choose a different model - and if so, why?

[Lomax]

Side note: I found some great looking mini ovens from Panasonic, which are only available in Japan and only as 100V models. So while they look pretty nice, they're not on my list, but I wanted to show them anyway Putting the control panel below the oven door seems eminently sensible to me, when designing a unit for small footprint/bench-top use. I don't understand why this configuration is so rare? The only ovens I've found on the European market that are laid out like this are from Moulinex (see updated list in first post), and these look quite flimsy.

[Owen]

P.S. If you're having trouble with the thermal switch, why not just bypass it?

I wouldn't call it trouble it's just a thing to watch out: I did some measurements and cycled the oven 5 times from 25° up to 230°C, let it cool down to 50°C and so on. While doing this i've noticed that the switch came earlier with after the third cycle and it took longer to reach 230°C. It wasn't a show stopper and after 60 boards or so with this oven i'm not worried about it because every single board went well (up to 4 layer boards with 0201 parts et cetera). So it became my trusty little reflow setup .

[Lomax]

Ok, since no-one jumped in to stop me, I have now purchased a (refurbished) "Lakeland Electric Compact Mini Oven" for £65 delivered. As tempted as I was by the Steba KB 14, which has many pluses, the non-coated cavity and stainless exterior tipped the balance in favour of the Lakeland oven. It's also much harder to get hold of (it was discontinued some time ago) and the only source I was able to find only had six of them left (now 4) - I figured I'd better take the chance now, before they're all gone. If anyone else is interested, this is the eBay listing.

[Neganur]

Don't forget the Severin series, e.g. TO 2034: https://www.beta-estore.com/rkuk/order_product_details.html?wg=1&p=16

I did look at Severin after seeing the EEVblog videos about the reflow kit from Beta Layout, which is based on the Severin TO 2034. This oven doesn't have a fan though, and it's a little big (20L), and it has a painted exterior with a lot of plastic. In my mind an Arduino controlled oven can be useful for many things - not only reflowing PCBs - some of which may require much higher temperatures than it was designed for. For this reason I'd prefer an oven that has a stainless exterior with few plastic parts, and a plain aluminium or steel interior that isn't coated (or has a ceramic coating). It may be an ambitious goal but it is my plan to buy preciesly one device to serve as "that box I can put stuff into to heat it up real good". For this reason I am now leaning towards the Dualit or Lakeland ovens (see below).

I don't think you'll regret your choice, it looks like a nice oven.

Just a heads up on the Severin though: the only plastic it has are the knobs, the handle and the feet. Pretty much like the other ovens you listed.
I don't know what to think regarding convection vs. just heating rods. Maybe it doesn't matter since there is so little volume and I remember some claiming that the heating ramp was not fast enough compared to pure rod ovens. No idea.

[Lomax]

I don't think you'll regret your choice, it looks like a nice oven. Just a heads up on the Severin though: the only plastic it has are the knobs, the handle and the feet. Pretty much like the other ovens you listed. I don't know what to think regarding convection vs. just heating rods. Maybe it doesn't matter since there is so little volume and I remember some claiming that the heating ramp was not fast enough compared to pure rod ovens. No idea.

Thanks Neganur - it's a silly thing to get exited about I guess, but I'm really looking forward to having the ability to "cook" things in the workshop. There have been times when I've had to use my (not very clean) kitchen oven for non-food jobs, and I've been equally worried about the burnt gunk it's covered with contaminating my projects and the possibility that the next pizza I make might kill me Not to mention not having the faintest idea what the actual temperature is, or the over-powerful convection fan at the back disrupting things and splattering them with all sorts. I do a lot of spray painting of small parts, and the ability to "bake" what I've painted in a clean environment is very welcome. And I've got a MacBook Air 11" with a glitching GPU that I hope to fix by reflowing the motherboard. And I've got a whole bag of 25g silica gel pouches which have been "used up" and need drying out (living by the coast I'm dependent on these). In short; I'm sure this oven will prove a valuable addition!

Thanks also for the additional info about the Severin ovens - I thought much of the front was plastic on these, happy to hear that's not the case(!), though I think I'd still go for the one I picked; while the convection fan might not be that useful for reflowing PCBs, it is essential for many other jobs, and I do like the stainless steel housing. One way to improve the thermal responsiveness would be to add additional heating elements, I've seen this done for DIY reflow ovens, and even some where the metal elements have been replaced by quartz ones. Just having the enclosure opens a lot of possibilities I think!

[Lomax]

Ok, so my Lakeland oven arrived a couple of days ago, but it turned out to be DoA; only the hum of a transformer could be heard when plugging it in. After some discussion with Lakeland customer services - who were very friendly and helpful - it was agreed that I would keep the oven but with a substantial discount. All the remaining units had been sold, so a replacement was not an option, and the money I saved would allow me to pay for a reflow controller to replace the faulty built-in one. Unless it turned out to be fixable of course! As soon as the deal was made I busied myself with opening up the oven, which turned out to be surprisingly fiddly for two reasons: first, the feet, which have to be removed, are attached with triangular "TA" type screws, which I didn't have any drivers for, so I had to make one by grinding down a small Robertson bit. Secondly, in order to remove the cover you have to remove four screws on the rear of the front panel (ringed in red in photo below), needing a driver with a 30cm+ long blade to reach. Luckily I have a ridiculously long home-made 1/4" hex extender which saved the day. Once the cover was removed, it immediately became apparent what the likely problem was: the controller is shielded with a thin sheet of metal, which also acts as a duct for a small cooling fan at the bottom of the cabinet, and this had been forcefully bent into the controller PCB. I bent it back into shape and noted that no damage had been done to the PCB - however the pin header connector at the top had been partly dislodged; pushing this connector back in brought the oven back to life! Some photos:

[Fred27]

Sounds perfect. I hope it works out well. It'll be a bonus if the electronics area stays cool enough to put a reflow controller in there.

[Lomax]

Some further observations after re-assembly:

Set to 230° (the highest setting), and with the convection fan switched on, it takes 3m45s before the controller switches off the heating elements. I'm still waiting for the digital thermometer that I've ordered to arrive, so I have no way to verify if indeed it reaches 230° - or even overshoots it - but based on this simple test it does look a little sluggish. I will be adding ceramic fibre insulation mats to the sides and bottom, which currently have no insulation, and I need to see what the back looks like as well (I forgot to check this when I had it open!). If I'm still unable to get a ~2°/s ramp-up I might look at adding an extra element at the bottom, and maybe one at the top as well.

The overall build quality is as one might expect from a cheap Chinese oven; all sheet metal is of the thinnest and softest type, and one has to take care when dismantling so as not to cut oneself. It is also very easy to bend and dent things, and care must be taken not to overtighten any screws. The exterior shell is not "proper" stainless steel, but some cheaper ferritic alloy (400 type), which became clear when I was trying to navigate my magnetic bit-holder with screw deep inside during reassembly; the bit-holder (and screws!) would happily stick to the shell, making reassembly a rather frustrating exercise.

That said, there are some better bits: the convection fan motor looks quite nice, and so does the ceramic light bulb holder. The PCBs for the controller are of the "FR-4" type and look to be well made. Unsurprisingly, it doesn't use SSRs to control the heating elements, but mechanical relays, though they are a hefty 10A 250V type. Since it has a digital controller it is also equipped with a (probably K-type) thermocouple (this can be seen to the left of the lamp socket), and all most of the wiring is a fiberglass insulated type. Interestingly, there are two tiny SCRs mounted on the power PCB - I expect these are used to control the light and convection fan, though I don't understand why an SCR would be chosen for this? Maybe the PCB labelling is misleading. In any case, once I get around to replacing the controller, there will be plenty of interesting and useful left-overs; one thermocouple, two relays, one high-temperature lamp holder, one 50x50mm 12V cooling fan, a piezo-electric buzzer, two rotary encoders, one small 10V transformer, a bright blue LED backlight plate, and a few PCB mounted push-buttons. More photos:

[engineertype]

Nice looking oven, but not surprising that it under-performs.  This is a very large oven (lots of thermal mass) and at 1.3kW it is under-powered.  This can be remedied though:
1. Add a lot of insulation, both inside and outside the oven chamber.  Don't skimp here - you'll regret it later
2. Add a thin aluminium (or copper) sheet to rest your PCB's on.  Aluminium and copper (used by heat sinks) conduct heat far better than steel.  Also, a solid sheet is better than the steel grate that comes with the oven - unless you like tan lines on your PCB's 
You might want to rest the aluminium sheet on top of the steel grate, which is fine.  Just remember to remove as many of the grate bars as possible to reduce thermal mass.
3. You should consider adding an additional heating element, especially if you plan to use lead-free solder paste.  The rate of rise of temperature in the reflow phase is pretty steep.

Reducing hot and cold spots is very important.  A well insulated, powerful oven means the heating elements don't have to be on 100% of the time.  As you might imagine, a brightly glowing element can easily create a hot spot.  Another thing to consider is the direction of the heat; ideally the top heating elements are not used much to minimize the exposure of the components to heat.  This is especially true if the oven's elements are infrared, which is better absorbed by dark components (like microcontrollers) and reflected by lighter ones.  It is good to see your oven uses resistive elements - this is a plus.

Your list of ovens is very useful.  I make and sell ControLeo2 reflow controller and often have customers in Europe asking me to recommend ovens.

<shameless plug>
ControLeo2 is the only reflow oven controller offering multi-relay support so you can control the direction of the heat (top Vs. bottom).  http://whizoo.com
</shameless plug>

[IconicPCB]

If your oven uses calrods ( 6 to 8 mm diameter heater rods ) consider adding cooling fins onto the rods to improve effectiveness of the fan.

These cooling fins often come as a sheet metal spiral to enhance the heat transfer from rod to air. If unavailable attach aluminium strip to the rod to improve heating effectiveness.
Do not be worried by increased thermal mass of the heater. IT IS ALL GOOD. You need an oven with decent thermal mass to ensure proper process window. You achieve good effective thermal mass by controlling temperature which is further enhanced by the action of convection fan.

At 1.3Kw the oven will not be able to handle a multilayer board. You will be lucky to process a double euro format double sided board in the oven.

Seriously double and triple installed power or at least increase installed power to reach the limit of the householed power socket ( may be 2.5Kw).

[Lomax]

If your oven uses calrods ( 6 to 8 mm diameter heater rods ) consider adding cooling fins onto the rods to improve effectiveness of the fan.

These cooling fins often come as a sheet metal spiral to enhance the heat transfer from rod to air. If unavailable attach aluminium strip to the rod to improve heating effectiveness.
Do not be worried by increased thermal mass of the heater. IT IS ALL GOOD. You need an oven with decent thermal mass to ensure proper process window. You achieve good effective thermal mass by controlling temperature which is further enhanced by the action of convection fan.

At 1.3Kw the oven will not be able to handle a multilayer board. You will be lucky to process a double euro format double sided board in the oven.

Seriously double and triple installed power or at least increase installed power to reach the limit of the householed power socket ( may be 2.5Kw).

Thank you, some great tips there! I'll definitely keep an eye out for those spiral heat-sinks, sounds like a simple way to improve the performance a little bit. TBH, I haven't really used the oven to do any reflows, apart from a simple test on a piece of veroboard, which came out brilliant. I have used it to dry two lots of silica gel pouches, heat up a piece of acrylic i needed to bend to a shape. and to harden the paint-job on a tripod mount for a vintage camera I've been restoring (pictured). It works very well, and I'm happy with my purchase!

[EPLan]

Is it worth adding this oven to the thread?

Gourmetmaxx Infrarot-Ofen, 9 L




1000 watt, 9 litre, two quartz elements - delivered to the UK from Amazon Germany for £32.85

Link

Reflow conversion guide here (you may need Chrome's auto-translate feature) -

http://wiki.ccc-ffm.de/projekte:reflowofen:start

[doobedoobedo]

I've converted one of those. I got it in Aldi branded as 'Crofton'.

It's a little slow to heat up but does the job. I've been thinking about adding a couple more heating elements if I can find another one cheap enough.

[timgiles]

I have one (Gourmetmaxx Infrarot-Ofen 9 L) and it is on the way this morning from Amazon.de to me (in Sweden). I have ordered a 450W element and likely will get a second in addition to the 1000W ish it has as standard. Initially going with the ControLeo2 controller but also wondering about rolling my own later in the year.

I was wondering if I should install the 3rd (and 4th) in the bottom or top or both.

Looking forward to getting it up and running soon - have a four layer board and two 2 layer board coming in end of May that will be perfect for reflow.

[doobedoobedo]

I rolled my own arduino based controller. It was pretty easy really.

[EPLan]

I rolled my own arduino based controller. It was pretty easy really.

Are you getting the 1.5C/s rise the German site displayed?

[doobedoobedo]

I rolled my own arduino based controller. It was pretty easy really.

Are you getting the 1.5C/s rise the German site displayed?

No. That's why I want more heating elements. I've already insulated using fibreglass from fire blankets. I'd say I get ~1C/s.

[EPLan]

Are you getting the 1.5C/s rise the German site displayed?

No. That's why I want more heating elements. I've already insulated using fibreglass from fire blankets. I'd say I get ~1C/s.

Ah, I actually ordered one based on the CCC link, and like you I cannot get anything more than almost 1C/s max no matter what I've tried(I have the insulation etc). Bit confused as to how the guy got that figure - the Chaos Computer Club is pretty well known.

Do you have any elements(any links to products?) in mind? I'm unfamiliar with all this but it seems to be a choice between single elements plus connectors or an all-in-one unit like this(oven seems to be 250mm internally so a tight but possible fit - EDIT: or maybe not, I'll have to investigate).

[timgiles]

Well I dont know about the germans build, but I plan to :

1. Use high temperature sealent to  seal the oven interior
2. Line the inside with car exhaust blanket rated to 1000oC - Ill use exhaust paste to ensure it sticks - I have a few different high temp pastes to try
3. Cover this with gold reflective fabric/tape (Reflect-a-gold) - almost the whole interior
4. Cover most of the glass door with the same gold tape, leaving a viewing slot
5. On the outside, between the over wall and exterior wall - insulated with the same blanket fabric
6. I am installing a normal heating element (not quartz) in the bottom of the over as a booster element (450W) - but I do like the 1kW quartz element you posted.... so this might find its way in there if the 450W is found wanting. I am thinking it might be a good replacement for the 500W quartz top element in it as standard.

My aim is to use the gold tape to reflect as much radiation around the inside and use the internal and external blankets to limit the thermal loss. My oven arrives early this week coming (1st week May). Ill take pictures and post results once the build is complete.

Good luck with your builds.

[timgiles]

If you need an additional heather element - you could try these cartridge elements:

           ebay search for: heating element cartridge

and add in your voltage (ie. 240V or 110V)

As mentioned, I went for a 450W element. The advice I got was to add it to the bottom of the oven. I will add a section of 0.8 or 1mm aluminium directly underneath the element so it does not burn the additional insulation. Proximity can be an issue for insulation even when it is rated much higher than the temperatures you'll get to in the oven.

If you are looking for the gold reflective tape - ebay search for: Reflect A Gold reflective tape

[nali]

If you need an additional heather element - you could try these cartridge elements:

           ebay search for: heating element cartridge

and add in your voltage (ie. 240V or 110V)

As mentioned, I went for a 450W element. The advice I got was to add it to the bottom of the oven. I will add a section of 0.8 or 1mm aluminium directly underneath the element so it does not burn the additional insulation. Proximity can be an issue for insulation even when it is rated much higher than the temperatures you'll get to in the oven.

If you are looking for the gold reflective tape - ebay search for: Reflect A Gold reflective tape

I replaced the elements in my oven with quartz elements salvaged from an A4 laser printer fuser unit which were almost exactly the same size. I can't remember their power but I think they're 500-ish W.

For covering the glass door I bought one of those disposable meat roasting trays from the supermarket which are basically alu foil but thick enough to hold shape once you've cut out a template (with holding tabs) from the base and fitted it around the glass.

[doobedoobedo]

If you need an additional heather element - you could try these cartridge elements:

           ebay search for: heating element cartridge

and add in your voltage (ie. 240V or 110V)

As mentioned, I went for a 450W element. The advice I got was to add it to the bottom of the oven. I will add a section of 0.8 or 1mm aluminium directly underneath the element so it does not burn the additional insulation. Proximity can be an issue for insulation even when it is rated much higher than the temperatures you'll get to in the oven.

If you are looking for the gold reflective tape - ebay search for: Reflect A Gold reflective tape

Cheers for the tip on the heating elements. They're cheap enough to just take a punt. I went for 3x300W ones. I might add some fins to aid in heat transfer if they need it.

I'm insulating externally with glass fibre cloth from cheap fire blankets  (ebay search for 'fire blanket' ) I used about 4 or 5 layers on all the metal sides, pop-riveted in place. I'm not bothering with the gold tape.

[blacksheeplogic]

No. That's why I want more heating elements. I've already insulated using fibreglass from fire blankets. I'd say I get ~1C/s.

I don't really see the issue you are trying to solve. The bulk time where this would have significant time impact is during the preheat phase and while 1C/s is a little low it's not outrageous, if your target is 150C within an initial temp of 20C  (sensor on the PCB), that's around 130 seconds at 1C/s, and at 1.5C/s it's 87 seconds. The remaining profile lets say is around 400 seconds including cooling your looking at 530 seconds verses 487 seconds which is <10%.

A modified toaster oven is not going to hit 3C/s to 5C/s peek rise during reflow, but thats OK with a 1.5C/s vrs 1.0C/s any component that fails due to that difference was a candidate for early failure anyway and probably a issue in the profile anyway.

[microcircuit]

I already own a T962A oven which has an inaccurate temp/timing controller. I am therefore looking at fitting an accurate controller so that it is a useful SMD oven. Has anyone any information if the ControLeo2 would be suitable for the T962A.
Phil.

[TIOUK]

If you have a T-962 you need to flash the firmware here: https://github.com/UnifiedEngineering/T-962-improvements  I had great results.

[l0wside]

The modification is perfect to spend a relaxed evening, with a DS18B20 (or MAX31820), some Kapton tape, a leftover FET or BJT, and a USB to serial adapter, the T-962 is updated easily within two hours.

Keep in mind, however, that it is still an IR oven which does not have a sensor on the PCB. After setting the peak temperature to 250°C, my PCBs turned black. The smell is still hanging in my basement. Even if the temperature at the sensor may have been 250°C, it must have exceeded 300°C on the board itself.

[microcircuit]

Thanks for the response, I am aware of the mod and the problems that you both mention (TIOUK & IOwside) I was looking at completely replacing the controller to prevent the problem IOwside mentioned.
There was a controller available from ESTechnical which solved the problems with the T962 and T962A and turned it into a reliable SMD oven unfortunately this is no longer available for the foreseeable future due to their premises catching fire.
I was therefore looking at other controllers and the ControLeo2 seemed to be the best solution but before committing to this controller I was hoping to find further information from anyone that had experience in converting a T962A with a ControLeo2.   

[l0wside]

microcircuit, I do not think the controller hardware is bad. The oven has three issues: First, it is infrared, which will never be able to provide proper heat distribution. Look for hot air reflow or vapor phase to improve on this. Second, the included firmware sucks, but this can be fixed (see the link which TIOUK mentioned). Third, the sensor is not on the board, but somewhere off. This might simply be a mechanical issue, but I have not yet investigated in detail. Replacing the controller board will not solve the third problem.

[bit.cyber]

So I've been looking at suitable toaster ovens that are easily available in France (four électrique / mini four). Amazon is easy and so this is where I've been looking.

Some candidates are:

• Spice 1380W 16L - https://www.amazon.fr/gp/product/B01LCOZPIE/ref=ox_sc_act_title_1?ie=UTF8&smid=A1JKIK5AIR193Q&th=1
• Severin 2034 1500W 20L - https://www.amazon.fr/gp/product/B003HD7YJC/ref=ox_sc_sfl_title_3?ie=UTF8&psc=1&smid=A1X6FK5RDHNB96
• Techwood 1200W 18L - https://www.amazon.fr/gp/product/B00H8BPQM6/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A1X6FK5RDHNB96
• Kooper 1400W ??L - https://www.amazon.fr/gp/product/B01LZHXNPI/ref=ox_sc_sfl_title_2?ie=UTF8&psc=1&smid=A1X6FK5RDHNB96

(The last one doesn't have the size listed but looks small'ish based on the external dimensions of 28 x 41 x 27 cm. But it looks OK and should be easy to mount the door opener as part of the ControLeo2 controller I intend to use.)

Any thoughts on what would work best?
Should I focus on smaller size rather than power, given I'll modify the oven with one of more additional heating elements? And is convection something that is advantageous or not, and given the price point likely not available. Or do they all fall into the 'much the muchness' category?

Thanks in advance.

[mikeselectricstuff]

So I've been looking at suitable toaster ovens that are easily available in France (four électrique / mini four). Amazon is easy and so this is where I've been looking.

Some candidates are:

• Spice 1380W 16L - https://www.amazon.fr/gp/product/B01LCOZPIE/ref=ox_sc_act_title_1?ie=UTF8&smid=A1JKIK5AIR193Q&th=1
• Severin 2034 1500W 20L - https://www.amazon.fr/gp/product/B003HD7YJC/ref=ox_sc_sfl_title_3?ie=UTF8&psc=1&smid=A1X6FK5RDHNB96
• Techwood 1200W 18L - https://www.amazon.fr/gp/product/B00H8BPQM6/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A1X6FK5RDHNB96
• Kooper 1400W ??L - https://www.amazon.fr/gp/product/B01LZHXNPI/ref=ox_sc_sfl_title_2?ie=UTF8&psc=1&smid=A1X6FK5RDHNB96

(The last one doesn't have the size listed but looks small'ish based on the external dimensions of 28 x 41 x 27 cm. But it looks OK and should be easy to mount the door opener as part of the ControLeo2 controller I intend to use.)

Any thoughts on what would work best?
Should I focus on smaller size rather than power, given I'll modify the oven with one of more additional heating elements? And is convection something that is advantageous or not, and given the price point likely not available. Or do they all fall into the 'much the muchness' category?

Thanks in advance.

If you can, it's worth going into a big store where you can actually see them, so you can check details like how the door opens, visibility etc.

[IconicPCB]

Convection ( fan forced ) is very important.
The effect of the fan is to increase effective thermal mass of the oven and provide a better distribution of heat to the product being soldered.

[jgfrm]

Hi Guys,

I want to build an oven based on the ControLeo2.
However, here in The Netherlands, the Boom Mat seems to be unavailable.
The mat has a reflection part that ensures that the heat is spread over the board.
Does anyone has a recommendation to buy the Boom Mat in NL/Europe, or a similar product?

Best,

-- Jaap

[plazma]

Is this model any good?


It's less than 40€ at Lidl.

Sent from my PLK-L01 using Tapatalk

[Mark]

I used a Cookworks mini oven from Argos, the models may change slightly but it's very similar to the Cookworks KR-107-23 (C), see manual for KWS1525R-F2U:

http://www.argos.co.uk/product/4234834
It is 4 element 1500W, fan assisted. 




Other parts:
0.9mm thick aluminium sheet for the shelf (ebay)
6" boost element Cartridge Heater, 350W, RS components # 860-7081
Kudom 10 A Solid State Relays x3 KSIM380D10-L
ControLeo 2 (ebay USA). 
Reflect-a-gold for oven interior (ebay)
Ceramic wool for insulation (ebay)

Using Multicore MP200 solder paste and a 215C peak, I get good results. 

[Lomax]

Using Multicore MP200 solder paste and a 215C peak, I get good results.

You do indeed - impressive! Is that a "weapon of mass destruction" (Weller WMD) I see in the background?

Edit: "Weapon of mass desoldering"?

[floobydust]

I use the OsPID, Open Source PiD controller for DIY reflow oven http://ospid.com/blog/
Arduino doing the control, so it's easy to make changes.

[jmelson]

I got a Philps P&P machine in 2007 and came up with my own reflow oven scheme.  I got the biggest GE toaster oven they had at our WalMart store.  It will hold a board up to 8 x 11" or so, which I occasionally do.  I got a ramp and soak temperature controller on eBay and some really small thermocouple extension wire.  When I tried to do the reflow with the thermocouple just in the air, it fried the boards black.  So, I poke the thermocouple into a through hole in the board, and it controls the actual board temperature.  I do both leaded and lead-free soldering, and adjust the final temp for the solder being used.  The ramp and soak controller can be set for degrees at start and end of the ramp and time of the ramp.  So, I have it programmed for ramp to 180 C, hold for 1 minute, ramp to desired temp, hold 1 minute, then cool down.

The oven has 4 heating elements that run horizontally, two above the rack, two below.  The elements run the full length left to right.  I made some rectangular rings out of stainless steel rod that sit on the racks.  As I usually have parts on both sides of the boards, I do the backs first (usually just decoupling caps and small passives) then do the top side with the chips.  The wire rings keep the back side components from touching the rack.

I have had very good results with this, and have done over 1000 boards.

Jon

[bit.cyber]

I was able to source the Boom Mat in Europe at a couple of different auto suppliers. Typically high performance / race car accessory suppliers.
Specifically I purchased suitable Boom Mat from TurboZentrum in Berlin, Germany.

There's a related thread which I started detailing my efforts: https://www.eevblog.com/forum/projects/adventures-in-home-reflow-toaster-oven-conversion/msg1177124/#msg1177124

Plus also check out my website with relevant postings: http://lagrangianpoint.net/tag/reflow/

[Podrowski]

I know this is an older topic, but since it's referred to from the build guide on the Whizzo website it seems like the right place.

Another usable candidate for a reflow oven could be the Rommelsbacher BG950 'Speedy'. I'ts a 10 liter model, slightly bigger than the Steba KB 11. It has a top and bottom quarz heating element for a total 950 watts heating power. It also allows for the tray to be positioned exactly between the elements. It is a little low on power, but it's also quite cheap when buying from German Amazon, so you could buy two and use the heating elements of the second oven to double up on heating power.

[ElektroQuark]

You can see my attempts for a reflow oven HERE.

It uses the Andy Brown reflow controller.
It's a 10 liter one, very small, vey cheap.
You will see how a resistance heating element fails at trying to maintain the correct profile.

[okp]

Hey, I got my Controleo3; but can't find a small good oven. Any support is welcome !

https://www.eevblog.com/forum/beginners/reflow-oven-controleo3-in-eu/msg1376160/#msg1376160

[ironcurtain]

I have been looking through Amazon for my country and Germany, considering these:

https://www.amazon.es/dp/B01LCOF9PI/_encoding=UTF8?coliid=I3LCQYFQHSMOHY&colid=EWIJYZXBUT9K&psc=1
https://www.amazon.de/Spice-Habanero-elektrischer-Umluftofen-5-6-verschiedene/dp/B01LCOF9PI
(convection, Spice - Habanero electric convection oven - 23 - 31 - 40 liters - 1380 - 1500 watts)

https://www.amazon.es/dp/B01MF5ORJ0/_encoding=UTF8?coliid=I1ME95WUL31JW0&colid=EWIJYZXBUT9K&psc=0
https://www.amazon.de/TZS-First-Austria-Innenbeleuchtung-Doppelglast%C3%BCr/dp/B01MF5ORJ0
(TZS First Austria - 19 Liter Minibackofen mit Krümelblech | 1380 Watt | Innenbeleuchtung | Umluft | Mini Pizza-Ofen | Doppelglastür | Timer | Backofen | Mini Backofen | Pizzaofen)
Probably my first choice, it seems well built and it's also a convection oven. Two heating elements plus fan and under 80 eur.

https://www.amazon.es/dp/B0079WCPFU/_encoding=UTF8?coliid=I1QCG270VWF3KO&colid=EWIJYZXBUT9K&psc=0
Probably my second choice, though the Spice is even cheaper. Looks solid, not sure if it has a fan. No information on heating elements.

https://www.amazon.es/dp/B01CI2JX5U/_encoding=UTF8?coliid=I3GRFSW1PW03F4&colid=EWIJYZXBUT9K&psc=1
(Moulinex Optimo, seems like you just pay for the brand here)

I have a few boards that will be a PITA to do by hand, so I'm more or less rushed to get this build started. Any comments? I hope this helps other people too.

[TIOUK]

For more heat input add these, worked for me.

https://www.ebay.co.uk/itm/CATERING-PUSH-FIT-COMPLETE-SET-HEAT-LAMP-AND-HOLDER-GANTRY-Lamp-Holder-220mm-R7S-/302084035412?hash=item46559c9354

[yiancar]

A bit of an old thread but.. here we go.

My attempted solution to our 230V problem is to combine 2 relatively big 120V ovens. Ill document as much as I can.

Firstly the ovens I chose where this B+D ones https://www.amazon.com/BLACK-DECKER-TO3250XSB-Convection-Countertop/dp/B00LU2I428/.

Firstly I disassembled one and got the elements out. It was pretty easy, just some metal tabs.

Then copied the cutouts over to the other oven. I tried to space them out as best as I could but the back element is very close to the back wall. I hope this is not going to be a problem.

I am heading to buy some high temp silicone to secure the elements in place and then wire them in series. They are rated for 650W 60V so 4 will do the job.

Ill keep you posted:)

[floobydust]

I use an open source Arduino with RocketScream Reflow Oven Controller Shield. It is discontinued but the sketch and schematic are very simple. Replaced by the Tiny Reflow Controller using dedicated ATtiny1634.
Point is, using Arduino you can change the software to your exact needs. It's a basic state-machine.
Avoid crapola MAX6675 thermopcouple-to-digital IC, it is terrible and picks up hum, cellphone RF etc and causes your reflow profile to malfunction due to temp readings being noisy. The newer MAX31856 I have not tried.

[doobedoobedo]

I used one of the ovens Aldi sell from time to time. Rolled my own controller from an arduino pro-mini, a MAX6675 (which works just fine), a little OLED and 3 buttons.

There's no real need for PID on these, mine samples the temperature and switches on or off at 2Hz. It can store several different programs (I use it for drying wood, curing resin and tempering steel as well as soldering). It could use a little more power and I have some extra elements which I'll install when I eventually get round to it .

[floobydust]

Anyone using a convection oven?

[IconicPCB]

Yes

I am using  Kambrook convection oven.

No changes to the controller. st it to 150C and let it run for 3 minutes, change the set point to 250C and watch the solder paste melt. When melted switch it off. Open and let the PCB cool down with the oven for a couple of minutes and then remove.
Handles leaded and lead free paste.
!.5kW heating element.From 150C to finished about a minute and a half. 

[floobydust]

I figured the fan would be better. Stir up and distribute the hot air better, as long as it doesn't blow off SMT parts.

[IconicPCB]

The oven works by sharing heat with the dish it cooks.

The larger the thermal mass of the oven the more uniform the temperature.
The fan amplifies the thermal mass of the oven providing for a more uniform thermal profile.

[jmelson]

I figured the fan would be better. Stir up and distribute the hot air better, as long as it doesn't blow off SMT parts.

I have a toaster oven that I use for reflow soldering.  It has 4 linear elements, 2 above and 2 below the rack.  It also has a fan for convection.  I really have NOT noticed the fan does anything, and generally do not use it.  It is probably way too low volume.  Certainly NO WAY it would ever blow parts off the board!

Jon

[IconicPCB]

John....

Use the fan ....

even though it does not have the force especially since the elements are probably shorter wave length IR elements.

[jmelson]

John....

Use the fan ....

even though it does not have the force especially since the elements are probably shorter wave length IR elements.

I've used the fan, and NOT used it.  I can't find ANY DIFFERENCE in the finished boards.  I was hoping it would even out temp variations in the oven, but I don't see that.  it is a TINY little fan outside the oven, and may end up blowing a lot of outside air into the oven.

Jon

[yiancar]

My Controleo3 oven is finally done! Picture attached.

I have performed the learning cycle and it seems to be doing very well. The 240v conversion seems to work wonders.

I will be testing some PCBs with leaded paste. What paste do you guys use?

[IconicPCB]

Did you applythe gold reflective tape onto the glass door?
What is that product?

[yiancar]

Did you applythe gold reflective tape onto the glass door?
What is that product?

This is called Reflect-A-Gold. You can have a look here on the details of how I insulated the oven.
http://www.whizoo.com/reflowoven

[flasonsmts]

the reason that you built a small DIY reflow oven is you want to learn the thoery of reflow oven?