Heat Gun Question

[Renegade]

A learning electronics textbook that I'm reading recommends buying the cheapest heat gun I can find at my local hardware store, as opposed to buying a professional desoldering workstation. (This is for soldering/desoldering.)

I really don't want to drop a few hundred on a desoldering workstation, but I don't want to buy a heat gun that simply won't do what I need.

I understand that the kinds of heat guns in the hardware store have broader nozzles, and that this isn't very appropriate for soldering work. However, I can also narrow the nozzle there, so that's less of a concern (but still there).

However, I would like to hear some experienced opinions on the topic.

FWIW - I am just a beginner here, and not a professional. I am not doing commercial work, so some additional frustration from using non-professional tools is expected, and I'm ok with that.

(My first project to use a heat gun with will be a DSO138 oscilloscope DIY kit. I'll also give it a shot on some old motherboards to practice with it first.)


Any thoughts on heat guns for beginners on a budget?

[Jeroen3]

Heat guns from the hardware store have way too much airflow. All your SMD will fly away. But I used it once, for reflowing an SMD board with 1206 and other large stuff when the oven was broken. Lots of drifters and rework required....
Don't get one of those.

A cheap hot air station is not expensive $60 should get you one.

[AndyC_772]

It's not immediately obvious to me that there's anything in that kit that actually requires the use of a heat gun at all.

I tend to use mine for desoldering surface mount devices with more than a couple of pins. For soldering, a good quality soldering iron is all you need.

My heat gun is one of these:

http://www.farnell.com/datasheets/1832482.pdf

It's not a typical choice for fine electronics work, and I'm OK with that. The important thing is that its air flow can be turned down very low, which a cheap paint stripper won't do. Too much air simply blows components around, so you need something gentle.

[DivineChaos]

I purchased an AOYUE 850A++. It works reliably and was not bank breaking.

http://www.amazon.com/Aoyue-850A-Hot-Rework-Station/dp/B000I5JXA0/ref=sr_1_1?ie=UTF8&qid=1455394238&sr=8-1&keywords=aoyue+850a

[RobertHolcombe]

If you're only intending to use it for occasional reflow/rework then you'll probably get away with it, but I think a few things are worth mentioning; ergonomics, temperature regulation, and air flow rate.

Ergonomics should hopefully be obvious - heat guns which connect directly to mains are bulky and heavy compared to a dedicated hot air station.

Most heat guns have only one or two temperature settings and no temperature feedback loop - you'll have to be mindful of this and perhaps perform some measurements to determine what setting to use and at what working distance to safely achieve reflow temperature.

Air flow rate isn't adjustable on most hot air guns - if it is too high you will blow components away.

The DIY scope kit you linked comes with all SMD components already soldered to the PCB, you shouldn't need anything more than a basic soldering iron to assemble it

[joeqsmith]

For the kit you show, a good iron would be my choice.   

For my own hobby work, I bought a Weller 6966C that I have owned for well over 15 years now that I use for some surface mount repairs.   It's 250 Watts and is fairly easy to use.   It has given me no troubles at all.   

I also have a 475W Master-Mite that I have been happy with.   It's a little too high power for me to recommend using it to solder with.   

[uncle_bob]

Hi

Backing off a bit further:

Why do you need a heat gun / hot air tool? They are used primarily in surface mount work. We use them when doing rework and putting things like resistors and capacitors back on a board. They can also be used for part removal. I would not use one for normal leaded part soldering. To make them useful on a large / ground plane board, a pre-heat stage (box) is a nice thing to have. You can get an adequate one for $100 to $150.

What do you need worse? If you don't have a *good* temperature controlled iron with a number of tips, spend your money on that first. A hand held desoldering device (Soldapulit) would be next on the list. I might go for the pre-heat box ahead of the hot air tool.

What do I have .... a (probably 20 year old) Hakko. I got it very much used so I have no real idea of how old it is. I'm happy with it. I most certainly would *not* pay what a new one costs for the limited use I get out of it at home. I use a Metcal soldering iron. It is the same sort of thing. I'd buy a nice new Hakko iron (for a lot less money) rather than a Metcal for home use. I got what I have used for a lot less than they cost new.

Lots of decisions ...

Bob

[mstoer]

I bought a hardware store heat gun initially.  A Milwaukee MHT3300.  It has a lot of power settings and air flow speeds, but not suited to smd work at all.  I've used it to strip boards where I am salvaging components and it excels at that.   I then bought a low cost "overseas" hot air tool (W.E.P. 858D, but this name is one of many for the same tool). It's works nicely for smd jobs, heat shrinking in small areas, etc.   Cost me about $60 CDN and I think it was well worth it.

[wblock]

It's not immediately obvious to me that there's anything in that kit that actually requires the use of a heat gun at all.

There isn't, it says the surface-mount stuff is already soldered.

[uncle_bob]

Hi

Well, we seem to have (yet again) scared the original poster away from their own thread ....

Bob

[Renegade]

Well, we seem to have (yet again) scared the original poster away from their own thread ....

Nope. Just had some running around to do.

It's not immediately obvious to me that there's anything in that kit that actually requires the use of a heat gun at all.

There isn't, it says the surface-mount stuff is already soldered.

My bad. There are a couple versions of the kit. The one I have only has 1 SMD IC pre-soldered on. I still need to solder on all the other SMDs. (I wasn't aware of this when I first ordered it a couple months or so ago.)

I merely linked to that as it came up in search results and looked like a decent write up.

I bought a hardware store heat gun initially.  A Milwaukee MHT3300.  It has a lot of power settings and air flow speeds, but not suited to smd work at all.  I've used it to strip boards where I am salvaging components and it excels at that.   I then bought a low cost "overseas" hot air tool (W.E.P. 858D, but this name is one of many for the same tool). It's works nicely for smd jobs, heat shrinking in small areas, etc.   Cost me about $60 CDN and I think it was well worth it.

That makes a lot of sense. I enjoy destroying things  , and I have some board that I've not finished with yet, so a regular heat gun may still make sense.

And I've been wondering about those el cheapo hot air tools. Someone else above mentioned a good experience with one:

I purchased an AOYUE 850A++. It works reliably and was not bank breaking.

http://www.amazon.com/Aoyue-850A-Hot-Rework-Station/dp/B000I5JXA0/ref=sr_1_1?ie=UTF8&qid=1455394238&sr=8-1&keywords=aoyue+850a

So I'm gravitating towards something like that.

My heat gun is one of these:

http://www.farnell.com/datasheets/1832482.pdf

That's way out of the initial price range I wanted to get started with hot air.

Thanks for all the replies.

I'm going to look into cheap hot air stations and see what I can manage there. I'll also try to find a used plain heat gun for desoldering old boards.

[uncle_bob]

Hi

Ok, if you are going to do a board full of parts, get a pre-heat frame before you get a heat gun. You will eventually need both. You will get more bang for the buck out of the frame.

Bob

[Renegade]

Ok, if you are going to do a board full of parts, get a pre-heat frame before you get a heat gun. You will eventually need both. You will get more bang for the buck out of the frame.

My ignorance is oooozing...

What's a pre-heat frame? I searched, but didn't turn up anything that made sense.

I've been planning on turning a toaster oven into a reflow oven like you see in some Youtube videos and Instructables. (I'll of course use quite a few in figuring out what to do or not do, and I won't be relying on any single one for a "gospel".) Is that the same thing? Or is a pre-heat frame something else entirely?

Thanks again.

[uncle_bob]

My ignorance is oooozing...

What's a pre-heat frame? I searched, but didn't turn up anything that made sense.

I've been planning on turning a toaster oven into a reflow oven like you see in some Youtube videos and Instructables. (I'll of course use quite a few in figuring out what to do or not do, and I won't be relying on any single one for a "gospel".) Is that the same thing? Or is a pre-heat frame something else entirely?

Thanks again.

Hi

An Aoyue 853A++ is one example. There are a lot of others. Essentially it is a way to hold the board while you work on it and to pre-heat the board to a temperature that is closer to solder temperature. Boards with big ground planes take a while to heat up. A frame helps them get to heat. Things like bypass caps that have one end grounded will be easier with one. Big parts with soldered ground tabs will be *much* easier with one.

There really isn't a lot to one. You could indeed make one yourself. If you have a lot of mechanical bits lying around, it could be easy. If you have to buy all the parts, a pre-built one is cheaper.

Some of these are just the basic box with heater and not anything else. Others seem to have a full range of rework tools built into them. I suspect they get used as stand alone general purpose repair stations ...

Bob

Bob

[wblock]

My bad. There are a couple versions of the kit. The one I have only has 1 SMD IC pre-soldered on. I still need to solder on all the other SMDs. (I wasn't aware of this when I first ordered it a couple months or so ago.)

Okay.  Assuming you have a decent soldering iron, why not just solder those parts that way?  Much less risk of losing parts or overheating board or parts with an improvised tool.

[uncle_bob]

My bad. There are a couple versions of the kit. The one I have only has 1 SMD IC pre-soldered on. I still need to solder on all the other SMDs. (I wasn't aware of this when I first ordered it a couple months or so ago.)

Okay.  Assuming you have a decent soldering iron, why not just solder those parts that way?  Much less risk of losing parts or overheating board or parts with an improvised tool.

Hi

Simple answer - things like ceramic caps do not like having one end heated while the other is cold. They tend to crack. A hot air tool (or at least pre-heat) reduces this risk. The other reason is that doing a part one lead at a time actually exposes it to higher temperatures than a quicker (hot air) process that does all the leads at once.

Bob

[vk6zgo]

Don't knock a Hardware Store heat gun.
They come in very handy in an Electronics workshop--just not for soldering.

The closest they come to being useful for that is in pre-heating an entire board prior to hand soldering,as a cheap substitute for the "pre-heat frame"referred to by other posters.

Heat guns are great for heatshrink tubing,heating boards to find heat sensitive faults---very carefully.

I've only tried to use a Solder station's proper hot air source once---even that was hard to control & blew precious RF chip capacitors across the bench,so I'm not a big fan of those,either---put it down to the Grey Beard.

[uncle_bob]

Hi

With a good hot air tool (and some practice), you can do a very good job on SMD parts. You need the right tip, the right air adjustment, and the right temperature. They all interact a bit so there is indeed a bit of practice involved. If you are blowing part around, the air is to high and likely the temperature is to low.

Bob (the bald guy with the partially shaved gray stubble ...)

[Renegade]

An Aoyue 853A++ is one example.

The US price looks reasonable, but the Canadian price... no. Not in my price range for this. It's $414.50 and up.

I don't know why some of these things are just insanely priced here in the Great White North.

My bad. There are a couple versions of the kit. The one I have only has 1 SMD IC pre-soldered on. I still need to solder on all the other SMDs. (I wasn't aware of this when I first ordered it a couple months or so ago.)

Okay.  Assuming you have a decent soldering iron, why not just solder those parts that way?  Much less risk of losing parts or overheating board or parts with an improvised tool.

Hi

Simple answer - things like ceramic caps do not like having one end heated while the other is cold. They tend to crack. A hot air tool (or at least pre-heat) reduces this risk. The other reason is that doing a part one lead at a time actually exposes it to higher temperatures than a quicker (hot air) process that does all the leads at once.

Bob

That makes sense.

I have a Weller WLC100 station and a couple el cheapo irons that I no longer use. The Weller is far better.

Don't knock a Hardware Store heat gun.
They come in very handy in an Electronics workshop--just not for soldering.

The closest they come to being useful for that is in pre-heating an entire board prior to hand soldering,as a cheap substitute for the "pre-heat frame"referred to by other posters.

Heat guns are great for heatshrink tubing,heating boards to find heat sensitive faults---very carefully.

I've only tried to use a Solder station's proper hot air source once---even that was hard to control & blew precious RF chip capacitors across the bench,so I'm not a big fan of those,either---put it down to the Grey Beard.

Ok, I can see that.

Would it make sense to have a cheap heat gun aimed at and fixed higher than a board and then use that to heat the board up a bit to help with using a soldering iron when desoldering?

With a good hot air tool (and some practice), you can do a very good job on SMD parts. You need the right tip, the right air adjustment, and the right temperature. They all interact a bit so there is indeed a bit of practice involved. If you are blowing part around, the air is to high and likely the temperature is to low.

That also makes sense. I could manage that with a bit of experience.

Bob (the bald guy with the partially shaved gray stubble ...)

A friend of mine went grey at 20. Many years ago. I've got enough grey in my beard now, but the majority of that grey came from professional endeavours other than electronic engineering.


Again, thank you to everyone who has contributed. You've helped me understand more about what I need to do here.

[vk6zgo]

Hi Bob,
This was my last job before "pulling the plug" completely & retiring.

It started out as "come in for a couple of days & help out",& escalated from there.

The folks in the dear old PRC didn't quite understand that paralleling UHF RF power amplifiers required all of the amplifiers to be tuned to the same frequency,or their underrated "unbalance loads" would go up in smoke.

This led to me doing something I hadn't done for 20 years----sweeping amplifiers,whilst pushing chip capacitors around with toothpicks.
Of course,I had to remove them first to reposition them,which is where I fell foul of the heat gun.
Luckily,we found a source of  ATCeramics caps in the USA,& could replace the ones which flew away.

Getting replacement caps from the PRC would have taken weeks of back & forth emails.
One query,one confirmation,& the US ones were on the way!

[Armxnian]

Cheap one: Atten 858D, really good for beginners with restricted budget. I used this one from 2011 to 2014, generally usable, but far from good.
Better one: Quick 957DW, powered by a long life and quiet BLDC blower, good temp accuracy and stability. Some reported this model has kinky hoses (no pun intended), but mine works perfectly.

Isn't the atten a death trap? Might as well short the mains and use it as an arc welder. Where did you buy the quick from?

What about the sparkfun rework station. Anyone know if it's any good?

[sleemanj]

Hot air really isn't very useful in the initial soldering stage, despite what uncle_bob says.  It's very slow to use hot-air to solder up a board, painfully slow going.  I have never known any ceramic cap or resistor I have hand-soldered to fail.  Tin one pad of each 2-pad footprint, pickup part with tweezers, re-flow pad with iron, place part using iron tip as a stop, remove iron, solder other end. 

Works fine, a couple seconds per part, compared to, faff about placing solder-paste, place the part(s), get hot air gun, wait for gun to heat, direct hot air towards part, wait a painfully long time for part, board, and solder to heat and reflow (watching paint dry is more fun), move to next part...  who has time for that.  Only when there is no choice (no accessible pads etc) do I break out hot-air for parts of an initial assembly.

For rework, for removing a part and replacing it, hot air is indispensable, but get a proper hot air rework tool with adjustable heat, flow, and different nozzles, they are cheap as chips but worth their weight in gold.

[AndyC_772]

Hot air really isn't very useful in the initial soldering stage, despite what uncle_bob says.  It's very slow to use hot-air to solder up a board, painfully slow going.  I have never known any ceramic cap or resistor I have hand-soldered to fail.

+1

Soldering one end then the other is discouraged by component manufacturers, because it can indeed theoretically cause failures by thermal stress - but it happens so rarely that for lab and hobby use I wouldn't give such concerns a second thought.

I'd certainly never fuss around pre-heating a board, or buying special equipment to do so. You're not a contract manufacturer, being asked to reflow large, expensive ICs.

[ion]

I purchased an AOYUE 850A++. It works reliably and was not bank breaking.

I've used the similar 852A+ for a couple of years now and also found it reliable for SMD work.

Whatever you get, practise on a scrap board first - you'll probably scorch the board while getting used to the settings.

[ion]

... get hot air gun, wait for gun to heat, direct hot air towards part ...

Sure a soldering iron is a better choice most of the time, but the warm up time of the heat gun is one thing I can't complain about - just a few seconds, certainly faster than my iron.

Of course, if you have to wait an hour or two for the solder paste to reach room temperature it hardly matters.