Hot air soldering/desoldering - UK Vintage Radio Repair and Restoration Discussion Forum

G0HFCFrank · 22nd Oct 2017, 10:09 am

Not sure if I'm posting this in the right place but here goes.
Another group I belong to is concerned with the repair and restoration of mechanical musical instruments and one of the members there has been extolling the virtues of a hot air soldering/desoldering device and claims the airstream was hot enough to blue the head of a nail (clockmenders will understand).
I'm wondering if anyone in this group uses or has information about these gadgets? An Ebay search for "hot air solder rework" will show you the kit I'm talking about

Frank C.

robin coleman · 22nd Oct 2017, 10:58 am

I used to use a hot air rework gun for surface mount rework made by a company called pace.
Regards
Robin

Terry_VK5TM · 22nd Oct 2017, 12:28 pm

SMD Hot Air Rework Station is another name for them.

I have a Hakko clone that I use occasionally.

Variable temperature and airflow.
And yes, they can generate a very hot airflow.

Terry

MrBungle · 22nd Oct 2017, 12:33 pm

Pretty handy little things. Also for doing heatshrink.

The really cheap ones have a habit of blowing up occasionally.

They’re really the only option for getting some SMD parts off boards.

G6Tanuki · 22nd Oct 2017, 12:36 pm

Hot Air devices are widely used in production for SMD work: someone I know has used them successfully to reflow "Ball Grid Array" chips whose original soldering on some legacy turn-of-the-century laptops/games-consoles proved distinctly problematic.

I've also seen an electric hot-air-device used to deal with the lead-free solder on 22mm copper central-heating water-pipes. Apparently the use of traditional naked-flame blowlamps for pipework is now classed as a 'special risk process' by some builders and needs a separate risk-assessment for each job, whereas a hot-air-gun doesn't.

Boater Sam · 22nd Oct 2017, 1:10 pm

I use very hot air for reclaiming parts off pcbs, its called a blow lamp, works great.

dseymo1 · 22nd Oct 2017, 1:49 pm

I have one of the Chinese models, very useful for all sorts of things. I particularly like the proximity-sensing control: pick up the handpiece and it starts, put it down and it stops (following a cooling cycle), which is almost as good as a third hand sometimes.

evingar · 22nd Oct 2017, 2:03 pm

Quote:

Originally Posted by MrBungle

The really cheap ones have a habit of blowing up occasionally.

Yep, this is my experience as well. The Aoyue I had (and I believe other similar stuff using a variety of names) has a very crude non isolated triac controlled mains arrangement. When the element goes, it can easily touch the metal surround and go out with a bang - taking the control circuitry with it.

Having said that, it's cheap enough to start with and you can actually buy spares for the thing. Just make sure the case is properly earthed (unfortunately, far from a forgone conclusion - if you are buying at the bottom end of the market (circa £60) always take a look inside IMHO.

Radio Wrangler · 22nd Oct 2017, 2:06 pm

We had one of the chinese ones at work for a while and it was reasonably good, but someone must have dropped the handpiece and it took us a while to realise that it was blowing out glass fragments. Eventually what looked like the remains of a broken test-tube blew out.

We replaced it with a much more expensive OKI unit. To be honest it was no more effective at its job than the generic Chinese one had been. It never showered glass, but it went back soon after purchase with a failed heater. We got sent a new unit.

Most recently we've bought a couple of JBC hot-air stations and these are clearly in a league better than the OKI and the Hakko. I've got one sitting on my bench and I'm very taken with it for desoldering. Soldering is a different matter because you have to hold things in place against the airflow.

In a previous life I used a Pace hot-air rework station, but this needed a compressed air feed. It was very good.

So I've had experience of several levels of these devices. The Chinese one was very usefully effective, but not robust against carelessness. They should be fine in private ownership where the owner takes more care than on a shared lab bench.

Don't chuck the soldering iron, though, you'll still need it.

David

G0HZU_JMR · 22nd Oct 2017, 3:03 pm

I bought one of the Aoyue 857A hot air stations a couple of years ago and this is supposed to be a fairly heavy duty thing. So it can be used to remove large devices from a PCB. However, I'm not sure what temperatures you want to reach? I've never used the Aoyue beyond about 330degC and I always let it build up the temperature slowly and let it ramp down slowly to try and preserve the life of the element. But I expect it to go bang at some point when the element fails. I think it can go to 480degC but I've never tried to check this.

The other type of hot air soldering device is the old school Weller Pyropen. This can be used as a hot air blower or a soldering iron bit can be fitted to it.

This runs from butane as per a cigarette lighter and it is a fairly scary and noisy device to use. I've got one here (see image below) but haven't used it for many years. But I think it can reach 700degC air temperature in a very focussed spot.

It can burn a black spot into a PCB in a fraction of a second if set to a high output. We used to use these at work in the early 1990s but they really aren't a sensible choice for modern SMD work. Much better to be used for destructive purposes I think!

G0HZU_JMR · 22nd Oct 2017, 4:46 pm

I just remembered I also have a fairly meaty hot air gun here. It's a Stanley FATMAX model. I just dug out the box and it says it goes up to 600degC on the outside of the box. However I've never opened the box and used it so I can't say how well it works. I got it as a free (long service) gift at work a year or two ago along with a new Dremel 4000. Still never used that either!

But some of these hot air guns can go very hot. However, I think the Weller Pyropen can get very hot with the right blower tip fitted. It's a bit like a mini gas blow lamp and it is smaller than the hot air guns so easier to hold and use for fine work.

MrBungle · 22nd Oct 2017, 6:21 pm

I wouldn't use anything without strict temperature control for electronics work. There's a very narrow temperature window that's acceptable for most parts and that's time constrained as well.

If you apply it at too low a temperature, it'll not heat up quick enough to melt solder and stay within that time window causing destruction of the device or the pads to lift.

If you apply it at too high a temperature, it'll destroy the device and the board substrate.

Things like pyropens, DIY heatguns, blow lamps etc that I've seen mentioned above are 100% not suitable for this sort of thing. Even melting heat shrink is pushing it. The Dremel Versatip is terrible as well.

While the cheap ones do blow up, they do work. Mine was/is an Aoyue one. I haven't repaired it yet; think the element went. I haven't needed it recently, so I just steal my other half's craft heat gun for doing heat shrink. The really nice thing is the immense quantity of nozzles you can get. Makes it trivial to get an SMD package off a board in seconds.

Davey72 · 22nd Oct 2017, 6:36 pm

I have plastic welded using hot air gun but never heard of this. Limited and specialist applications am guessing.

As a vintage buff and a musician I am intrigued to hear more adventures here please.

evingar · 22nd Oct 2017, 7:35 pm

Quote:

Originally Posted by MrBungle

While the cheap ones do blow up, they do work. Mine was/is an Aoyue one. I haven't repaired it yet; think the element went. I haven't needed it recently, so I just steal my other half's craft heat gun for doing heat shrink. The really nice thing is the immense quantity of nozzles you can get. Makes it trivial to get an SMD package off a board in seconds.

I agree that they are very useable, but the one I had really didn't have any calibrated temperature control (it had a knob with a 1-10 marking) and I had to rely on "instinct".

Once I got the hang of it using scrapped boards - in association with the "works" calibrated Weller unit for reference - it was fine. When you consider the cost of Weller or Metcal / OKI hot air rework equipment in relation to the cost of the Chinese stuff, you can forgive the occasional blue flash and bang.

G0HZU_JMR · 22nd Oct 2017, 7:44 pm

Maybe I misinterpreted the original post? I assumed that Frank was asking about the possibility of using a hot air device (that was designed for electronics) for musical instrument repair work. That's why I mentioned the Pyropen and the hot air gun. These can generate very high temperatures compared to a modern hot air station designed for SMD electronics work. So they might be more suitable for the musical instrument repairs? Depends on how hot it needs to be I guess...

G0HZU_JMR · 22nd Oct 2017, 8:01 pm

Here's a scary youtube video of a couple of people misusing a Weller Pyropen. I'm not sure you are supposed to use it with the cat/tip removed but it does look impressive with that blue flame! I don't think I'll try this with mine. They aren't wearing any suitable safety gear either but they seem to be enjoying themselves.

https://www.youtube.com/watch?v=3xQ6FBMZWVM

kellys_eye · 22nd Oct 2017, 10:47 pm

ISTR that the cheap Chinese devices are rated for 220V

With the UK supply being anywhere up to 10% higher - and the propensity for Chinese equipment to be built VERY CLOSE to allowable limits - perhaps using them with a variac would be useful to extend their lifespan?

Perhaps even a triac motor speed controller with fixed resistance to set the output slightly lower than maximum?

Whilst accepting the occasional blow-up might be a tolerable solution I'd rather use the tool in safer circumstances.

MrBungle · 23rd Oct 2017, 12:35 am

My mains jumps around between 225v and 250v so that's a possibility.

Terry_VK5TM · 23rd Oct 2017, 1:16 am

Our mains is consistently above 255V.

If the rework station goes bang, will be sending the elec supply company the bill.

Terry

G0HFCFrank · 23rd Oct 2017, 6:02 pm

Thanks for all your replies folks, I think I will get one of these and use it through my variac (thanks, Kelly). Jeremy, Davey, The place I saw this was in a discussion about the best way to remove the dreaded white glue from pianola stacks. (these were originally stuck together with animal glue permitting straightforward repair, the white glue is a nightmare). Having read the comments on there I immediately wondered if it had an electronics application. It clearly has so thanks again.
Frank C.

22nd Oct 2017, 10:09 am	#1
G0HFCFrank Pentode Join Date: Oct 2011 Location: Oldham, Greater Manchester, UK. Posts: 167	Hot air soldering/desoldering Not sure if I'm posting this in the right place but here goes. Another group I belong to is concerned with the repair and restoration of mechanical musical instruments and one of the members there has been extolling the virtues of a hot air soldering/desoldering device and claims the airstream was hot enough to blue the head of a nail (clockmenders will understand). I'm wondering if anyone in this group uses or has information about these gadgets? An Ebay search for "hot air solder rework" will show you the kit I'm talking about Frank C.

22nd Oct 2017, 10:58 am	#2
robin coleman Hexode Join Date: Oct 2011 Location: Portsmouth, Hampshire, UK. Posts: 354	Re: Hot air soldering/desoldering I used to use a hot air rework gun for surface mount rework made by a company called pace. Regards Robin

22nd Oct 2017, 12:28 pm	#3
Terry_VK5TM Nonode Join Date: Oct 2010 Location: Tintinara, South Australia, Australia Posts: 2,339	Re: Hot air soldering/desoldering SMD Hot Air Rework Station is another name for them. I have a Hakko clone that I use occasionally. Variable temperature and airflow. And yes, they can generate a very hot airflow. Terry

22nd Oct 2017, 12:33 pm	#4
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hot air soldering/desoldering Pretty handy little things. Also for doing heatshrink. The really cheap ones have a habit of blowing up occasionally. They’re really the only option for getting some SMD parts off boards.

22nd Oct 2017, 12:36 pm	#5
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Hot air soldering/desoldering Hot Air devices are widely used in production for SMD work: someone I know has used them successfully to reflow "Ball Grid Array" chips whose original soldering on some legacy turn-of-the-century laptops/games-consoles proved distinctly problematic. I've also seen an electric hot-air-device used to deal with the lead-free solder on 22mm copper central-heating water-pipes. Apparently the use of traditional naked-flame blowlamps for pipework is now classed as a 'special risk process' by some builders and needs a separate risk-assessment for each job, whereas a hot-air-gun doesn't.

22nd Oct 2017, 1:10 pm	#6
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Hot air soldering/desoldering I use very hot air for reclaiming parts off pcbs, its called a blow lamp, works great.

22nd Oct 2017, 1:49 pm	#7
dseymo1 Retired Dormant Member Join Date: Dec 2007 Location: Shropshire, UK. Posts: 3,051	Re: Hot air soldering/desoldering I have one of the Chinese models, very useful for all sorts of things. I particularly like the proximity-sensing control: pick up the handpiece and it starts, put it down and it stops (following a cooling cycle), which is almost as good as a third hand sometimes.

22nd Oct 2017, 2:06 pm	#9
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,868	Re: Hot air soldering/desoldering We had one of the chinese ones at work for a while and it was reasonably good, but someone must have dropped the handpiece and it took us a while to realise that it was blowing out glass fragments. Eventually what looked like the remains of a broken test-tube blew out. We replaced it with a much more expensive OKI unit. To be honest it was no more effective at its job than the generic Chinese one had been. It never showered glass, but it went back soon after purchase with a failed heater. We got sent a new unit. Most recently we've bought a couple of JBC hot-air stations and these are clearly in a league better than the OKI and the Hakko. I've got one sitting on my bench and I'm very taken with it for desoldering. Soldering is a different matter because you have to hold things in place against the airflow. In a previous life I used a Pace hot-air rework station, but this needed a compressed air feed. It was very good. So I've had experience of several levels of these devices. The Chinese one was very usefully effective, but not robust against carelessness. They should be fine in private ownership where the owner takes more care than on a shared lab bench. Don't chuck the soldering iron, though, you'll still need it. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

22nd Oct 2017, 3:03 pm	#10
G0HZU_JMR Dekatron Join Date: Sep 2010 Location: Cheltenham, Gloucestershire, UK. Posts: 3,077	Re: Hot air soldering/desoldering I bought one of the Aoyue 857A hot air stations a couple of years ago and this is supposed to be a fairly heavy duty thing. So it can be used to remove large devices from a PCB. However, I'm not sure what temperatures you want to reach? I've never used the Aoyue beyond about 330degC and I always let it build up the temperature slowly and let it ramp down slowly to try and preserve the life of the element. But I expect it to go bang at some point when the element fails. I think it can go to 480degC but I've never tried to check this. The other type of hot air soldering device is the old school Weller Pyropen. This can be used as a hot air blower or a soldering iron bit can be fitted to it. This runs from butane as per a cigarette lighter and it is a fairly scary and noisy device to use. I've got one here (see image below) but haven't used it for many years. But I think it can reach 700degC air temperature in a very focussed spot. It can burn a black spot into a PCB in a fraction of a second if set to a high output. We used to use these at work in the early 1990s but they really aren't a sensible choice for modern SMD work. Much better to be used for destructive purposes I think! Attached Thumbnails __________________ Regards, Jeremy G0HZU

22nd Oct 2017, 4:46 pm	#11
G0HZU_JMR Dekatron Join Date: Sep 2010 Location: Cheltenham, Gloucestershire, UK. Posts: 3,077	Re: Hot air soldering/desoldering I just remembered I also have a fairly meaty hot air gun here. It's a Stanley FATMAX model. I just dug out the box and it says it goes up to 600degC on the outside of the box. However I've never opened the box and used it so I can't say how well it works. I got it as a free (long service) gift at work a year or two ago along with a new Dremel 4000. Still never used that either! But some of these hot air guns can go very hot. However, I think the Weller Pyropen can get very hot with the right blower tip fitted. It's a bit like a mini gas blow lamp and it is smaller than the hot air guns so easier to hold and use for fine work. __________________ Regards, Jeremy G0HZU

22nd Oct 2017, 6:21 pm	#12
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hot air soldering/desoldering I wouldn't use anything without strict temperature control for electronics work. There's a very narrow temperature window that's acceptable for most parts and that's time constrained as well. If you apply it at too low a temperature, it'll not heat up quick enough to melt solder and stay within that time window causing destruction of the device or the pads to lift. If you apply it at too high a temperature, it'll destroy the device and the board substrate. Things like pyropens, DIY heatguns, blow lamps etc that I've seen mentioned above are 100% not suitable for this sort of thing. Even melting heat shrink is pushing it. The Dremel Versatip is terrible as well. While the cheap ones do blow up, they do work. Mine was/is an Aoyue one. I haven't repaired it yet; think the element went. I haven't needed it recently, so I just steal my other half's craft heat gun for doing heat shrink. The really nice thing is the immense quantity of nozzles you can get. Makes it trivial to get an SMD package off a board in seconds.

22nd Oct 2017, 6:36 pm	#13
Davey72 Retired Dormant Member Join Date: Oct 2017 Location: Coventry, West Midlands, UK. Posts: 5	Re: Hot air soldering/desoldering I have plastic welded using hot air gun but never heard of this. Limited and specialist applications am guessing. As a vintage buff and a musician I am intrigued to hear more adventures here please.

22nd Oct 2017, 7:44 pm	#15
G0HZU_JMR Dekatron Join Date: Sep 2010 Location: Cheltenham, Gloucestershire, UK. Posts: 3,077	Re: Hot air soldering/desoldering Maybe I misinterpreted the original post? I assumed that Frank was asking about the possibility of using a hot air device (that was designed for electronics) for musical instrument repair work. That's why I mentioned the Pyropen and the hot air gun. These can generate very high temperatures compared to a modern hot air station designed for SMD electronics work. So they might be more suitable for the musical instrument repairs? Depends on how hot it needs to be I guess... __________________ Regards, Jeremy G0HZU

22nd Oct 2017, 8:01 pm	#16
G0HZU_JMR Dekatron Join Date: Sep 2010 Location: Cheltenham, Gloucestershire, UK. Posts: 3,077	Re: Hot air soldering/desoldering Here's a scary youtube video of a couple of people misusing a Weller Pyropen. I'm not sure you are supposed to use it with the cat/tip removed but it does look impressive with that blue flame! I don't think I'll try this with mine. They aren't wearing any suitable safety gear either but they seem to be enjoying themselves. https://www.youtube.com/watch?v=3xQ6FBMZWVM __________________ Regards, Jeremy G0HZU

22nd Oct 2017, 10:47 pm	#17
kellys_eye Octode Join Date: Jan 2014 Location: Oban, Scotland, UK. Posts: 1,129	Re: Hot air soldering/desoldering ISTR that the cheap Chinese devices are rated for 220V With the UK supply being anywhere up to 10% higher - and the propensity for Chinese equipment to be built VERY CLOSE to allowable limits - perhaps using them with a variac would be useful to extend their lifespan? Perhaps even a triac motor speed controller with fixed resistance to set the output slightly lower than maximum? Whilst accepting the occasional blow-up might be a tolerable solution I'd rather use the tool in safer circumstances.

23rd Oct 2017, 12:35 am	#18
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: Hot air soldering/desoldering My mains jumps around between 225v and 250v so that's a possibility.

23rd Oct 2017, 1:16 am	#19
Terry_VK5TM Nonode Join Date: Oct 2010 Location: Tintinara, South Australia, Australia Posts: 2,339	Re: Hot air soldering/desoldering Our mains is consistently above 255V. If the rework station goes bang, will be sending the elec supply company the bill. Terry

23rd Oct 2017, 6:02 pm	#20
G0HFCFrank Pentode Join Date: Oct 2011 Location: Oldham, Greater Manchester, UK. Posts: 167	Re: Hot air soldering/desoldering Thanks for all your replies folks, I think I will get one of these and use it through my variac (thanks, Kelly). Jeremy, Davey, The place I saw this was in a discussion about the best way to remove the dreaded white glue from pianola stacks. (these were originally stuck together with animal glue permitting straightforward repair, the white glue is a nightmare). Having read the comments on there I immediately wondered if it had an electronics application. It clearly has so thanks again. Frank C.