I would like to BORROW or BUY a reflow oven UK for a weekend

[cstratton]

Given you don't have an oven, you presumably also don't have an automatic pick and place.

So for the amount of parts you can place in a day or two by hand, you might as well just use a hot air tool with the speed dialed down.  I tend to do this under the soldering microscope at low power, so I can see and deal with any issues the develop as they happen.

Another option is to use the tool to heat the board from below.

Getting oven reflow to come out right requires skill and tuning which may not be there for a one-off board anyway.  (Even established prototype assembly vendors routinely have flow issues).

When you find a flaw in an oven-reflow board, you'll probably need the hot air tool to correct it anyway...

[ManCave]

Cstratton, you are right, I don't have an automatic p&p, but have built myself a manual one. Speeds up the process of placing components about 3-5 times, depending on how many BOM items there are.

I have and use hot air station in combination with a hotplate preheated to 150°C to pre-soak the boards. However, using hot air station to reflow is slow and time does scale up with the number of components on the board and the size of the board as you need to move the air tool around, so I mainly use this for prototypes. Now I have 30+ boards to assemble and reflow. It's also a lot less controlled (temperature-wise) with the hot-air tool and these are not prototype boards so I want them to function  ...and keep functioning.

I can tune the oven settings with a couple of boards to start with and then as long as the production boards are positioned in the same place every time on the same program, they should mostly come out good. Inspection is necessary, of course, and some re-work will probably be too, but doing this with hot-air station doesn't guarantee no solder bridges or fully reflowed under an exposed pad IC and rework might still be necessary. My feeling is that I'm only gaining by using the reflow oven in this particular situation.

[mk_]

[/quote]
What makes it stupid?
[/quote]

read https://www.eevblog.com/forum/reviews/deadly-insane-design-(cif-ft-02-reflow-oven)-teardown-rant-safety-fix/

and then how they solved this

https://www.eevblog.com/forum/reviews/deadly-insane-design-(cif-ft-02-reflow-oven)-teardown-rant-safety-fix/msg695441/#msg695441

[ManCave]

read https://www.eevblog.com/forum/reviews/deadly-insane-design-(cif-ft-02-reflow-oven)-teardown-rant-safety-fix/

and then how they solved this

https://www.eevblog.com/forum/reviews/deadly-insane-design-(cif-ft-02-reflow-oven)-teardown-rant-safety-fix/msg695441/#msg695441

oh wow!

[Acecool]

A lot of reflow ovens are way overpriced... and the Chinese ones aren't necessarily good...

You can, for around $100 USD, buy a good sized toaster oven, and the components to build your own... You may end up spending as much as $250 USD if you go overboard or for a much larger unit, etc.... or get a kit...

But, building it yourself, with a good kit, is a great option - it is something I am planning on doing myself too....


If I was in the UK and mine was done, I'd lend it in a heartbeat.......


Anyway - if you go the purchase route, you'll spend about 4 to 5 times what you'd spend if you built one yourself for the same quality.... so consider making your own.... Obviously this won't be done by Friday - because the kit requires delivery - but if you find one to borrow then consider this for later... Paying less also means spending more on other things later...

[PlainName]

if you go the purchase route, you'll spend about 4 to 5 times what you'd spend if you built one yourself for the same quality

That's often said but I think it is largely wishful thinking. For one, you're unlikely to have access to kit to make molds and custom fittings, so your homer is going to look like a homer, most probably. Next, you won't have the  many years of experience in developing the stuff, so you're going to spend a goodly amount of time finding all the pitfalls the manufacturer has already sorted out. It's quite likely that your first choice of components won't be quite right, so you'll be buying more because a) you have to buy 10-off to get one, b) you got the wrong thing the first time, and/or c) to replace the ones you broke.

Which is not saying one shouldn't make one's own kit - often, the pleasure of doing it is enough justification. But there are limits. Sometimes one wishes to use tools rather than spend ones spare time trying to replicate them.

[carl0s]

Whaddaya think of these? £22 quid!

It's got heaters top and bottom.

and the door looks like it will open gently. Not sure how well it'll keep the heat in mind.

https://www.ebay.co.uk/itm/Rosewill-RHTO-13001-1500-W-6-Slice-Black-Toaster-Oven-Broiler-with-Drip-Pan/123117961016?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I've ordered one anyway. I was thinking (searching) whether I should try Andy Brown's reflow controller, or the Controleo thing, but I think I might just eye-ball it all for now, after reading this discussion

Speaking of variacs BTW... would one of these do? It says 4kw, so I presume a proper variac rather than some kind of triac dimmer switch:
https://www.ebay.co.uk/itm/AC-220V-4000W-Variable-Voltage-Controller-For-Fan-Speed-Motor-temperature-Dimmer/192146732189?epid=13007568545&hash=item2cbcd6749d:g:YFQAAOSwIBxaemAZ

[PlainName]

It's got heaters top and bottom.

They are uncovered, so some parts of the board will scorch whilst others (in shadow) stay relatively cool.

[carl0s]

It's got heaters top and bottom.

They are uncovered, so some parts of the board will scorch whilst others (in shadow) stay relatively cool.

Do you think it's a reasonable starting point though? Also, I'm not expecting any large components on my boards to shadow any others.

[PlainName]

Maybe. The only real way to find out is to try it.

[chris_leyson]

They are uncovered, so some parts of the board will scorch whilst others (in shadow) stay relatively cool.

All toaster ovens have uncovered elements. I've got a Severin 1.5kW oven and the heaters are arranged exactly the same way, two on the top and two on the bottom. Never scorched anything and had every single joint reflow. I'm also using a 0.25mm thick piece of brass sheet on top of the grill to keep the heat distribution even, besides, as some of the boards I've reflowed are so small I need the brass sheet to stop them falling through the grill.

[PlainName]

All toaster ovens have uncovered elements

Mine doesn't. An Argos model from some years ago, the elements are hidden.

I'm also using a 0.25mm thick piece of brass sheet

So not quite uncovered

[chris_leyson]

So not quite uncovered

True, but I it's the air temperature that does most of the work, will have to measure later on just out of curiosity. Well I got that completely wrong. Measured the air temperature midway between the bottom element and the brass plate. When initially ramping the soak temperature up (around 100C) the air temerature was 10C hotter than the PCB but during reflow it was 60C cooler than PCB, so nothing to do with air temperature.

[mikeselectricstuff]

Getting oven reflow to come out right requires skill and tuning which may not be thee for a one-off board anyway.  (Even established prototype assembly vendors routinely have flow issues).

Not in my experience. Turn it on. wait for reflow, open the door.  Job done.
Obviously avoid lead-free paste

[Mr. Scram]

Not in my experience. Turn it on. wait for reflow, open the door.  Job done.
Obviously avoid lead-free paste

Isn't your business required to use it?

[mikeselectricstuff]

Speaking of variacs BTW... would one of these do? It says 4kw, so I presume a proper variac rather than some kind of triac dimmer switch:
https://www.ebay.co.uk/itm/AC-220V-4000W-Variable-Voltage-Controller-For-Fan-Speed-Motor-temperature-Dimmer/192146732189?epid=13007568545&hash=item2cbcd6749d:g:YFQAAOSwIBxaemAZ

That's not big enough to be a 4KVA variac, nowhere near

[mikeselectricstuff]

Not in my experience. Turn it on. wait for reflow, open the door.  Job done.
Obviously avoid lead-free paste

Isn't your business required to use it?

Who's gonna know?

[Acecool]

I only use lead-free...

There's no issue using it in a reflow oven - if you want a faster melt, simply mix additional flux in the paste..

[mikeselectricstuff]

I only use lead-free...

There's no issue using it in a reflow oven - if you want a faster melt, simply mix additional flux in the paste..

Leaded gives you a wider margin between "reflow" and "incinerate"

[Mr. Scram]

Who's gonna know?

Well, the internet now, I guess.