Heat gun advice - Page 1
Forum section: electronics / general

author: msknight
author_rank: Regular Contributor
timestamp: January 20, 2024, 10:41:53 pm
content: This is going to be an unnecessarily long one, just to get people to know where I'm going and what I need.Firstly, I'm working on retro 8 bit machines and occasionally have to remove chips. Being on a budget I have a ZD-915 desoldering tool, but as you know it gets 95% there and leaves enough pins with a small amount of led solder on, to prevent the chip from lifting clean.It obviously needs a small amount of directed heat to do enough melting to allow the chip to lift, but I'm having a heck of a job trying to find something. Obviously I've got larger heaters for removing mobile phone backs, but that's too large and delivers too much heat, to use on a 40 year old computer.I've been watching a number of videos and saw Adrian's Digital Basement where he uses a Gaoyue 858, but there seems to be little information about it. Looking it up on Amazon, I see reviews equally split across from 1 to 5 stars with people getting white smoke and destroying their units. Some of this sounds like it's down to not knowing how to use it properly... but that's another problem... I can't find any reliable information that would give me confidence to know that I wouldn't make the same mistake.So I'm asking here for advice and recommendations for a rework/heat unit that can finish the job of delivering enough focused heat over a chip to finish the job of lifting it, without over heating neighbouring components... and on a budget, as I'm a hobyist. Let's say £50 just to ball park it, but I can be flexible. If recommended unit have good numbers of videos/documents to demonstrate how to use it properly and safely, then that's a very welcome bonus.

author: jchw4
author_rank: Regular Contributor
timestamp: January 21, 2024, 08:13:29 am
content: Quote from: msknight on January 20, 2024, 10:41:53 pmDo not buy the heaters with the fan in the handle. Just stay away.Very loud, heavy and does not produce enough air. Prone to overheating and difficult to fix when the handle melts. It will definitely melt at some point because the fan does not produce enough air.I recently tried Quick 957DW+ and I can fully recommend it.https://www.tequipment.net/Quick/957DW+/Desoldering-Equipment/Rework-Stations/sells it for $105 now with free shipment. Probaby US-only but not should not be very far from your budget even in UK.It is much better than the old budget models:1) All-metal case, pretty quiet, claims 580W.2) Tool rest (magnetic) sensor in the handle! Will automatically cool down and stop when parked. I did not expect that for the price.No fancy controls but does exactly what you would expect. I did not disassemble the handle so I don't know what's inside.It's still cheap so do not expect anything fancy but I was very pleasantly surprised.QuoteI did not have a chance to try ZD-915, but I own Hakko and old Aoyue tools. I also had a chance to try a similar high-end Metcal tool once. I feel that they are all the same in terms of performance, the difference is only in maintenance and available options.In my experience none of them leave any significant (i.e. visible) amount of solder if you do it right. You need to make sure that the solder fully melts on the other side of the board. I usually look at the other side and wait for the pin to move freely around the hole before pressing the suction button. As you probably already know, there is usually a single chance to push the trigger.If it did not work the first time you will have to add fresh solder and start over.But usually it does not leave any solder residue. If it did then I made a mistake.

author: msknight
author_rank: Regular Contributor
timestamp: January 21, 2024, 08:39:36 am
content: Thanks very much for the advice. I have found a seller for that unit in the UK and for something that is reliable, I'll certainly jump to that price.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: January 21, 2024, 09:27:22 am
content: With regard to removing DIL type ICs, DO NOT USE HOT AIR... Hot air works well with SMD parts, but you risk board damage trying to heat through hole ICs. The safest way to minimise damage is to cut the legs close to the IC body, then heat each pad to remove the leg using narrow nose pliers or tweezers. Use a temperature controlled iron to reduce the risk of pad/track/board damage. Clear the holes with solder wick or a solder sucker, Using solder wick there is probably less risk of damage by overheating. Remember, it is cheaper to replace an IC than it is to replace the whole board.SJ

author: msknight
author_rank: Regular Contributor
timestamp: January 21, 2024, 09:46:20 am
content: Thanks SJ.I appreciate what you're saying about the heat, etc. However, on the vintage systems some chips are not replaceable, either not made any more, or operate at the wrong speeds. It's proving to be quite the problem, especially having to harvest parts from dead systems to make one living unit.

author: tooki
author_rank: Super Contributor
timestamp: January 21, 2024, 12:38:12 pm
content: Quote from: msknight on January 20, 2024, 10:41:53 pmBefore you buy anything, make sure your desoldering technique is correct. Your statement of getting “95% of the way there” tells me you’re not really having trouble getting the joints to melt, so it’s more likely incorrect technique that’s causing the issue.In another thread, I outline the proper technique and link a video that explains it extremely well. Others in the thread describe getting excellent results using this technique with the ZD-915, too.Quote from: tooki on December 27, 2020, 02:06:29 am

author: msknight
author_rank: Regular Contributor
timestamp: January 21, 2024, 01:36:29 pm
content: Sweat joints.... so that's the technical name.Thanks for all this. Watching and reviewing. Would be nice to have the space for the kind of equipment they're using :-)

author: armandine2
author_rank: Frequent Contributor
timestamp: January 21, 2024, 02:29:26 pm
content: I have just got myself a good small side cutter, Erem 670E, after ineptly de-soldering a replaceable chip.

author: madires
author_rank: Super Contributor
timestamp: January 21, 2024, 03:21:54 pm
content: Adding fresh solder helps with desoldering stubborn pins.

author: tooki
author_rank: Super Contributor
timestamp: January 22, 2024, 08:17:09 am
content: Quote from: msknight on January 21, 2024, 01:36:29 pmNah, be glad you don’t have the space, because that’s a $6000 rework system! :p

author: tooki
author_rank: Super Contributor
timestamp: January 22, 2024, 08:20:40 am
content: Quote from: armandine2 on January 21, 2024, 02:29:26 pmHow is the build quality? There’s been a precipitous drop in the quality of Erem tweezers over the past few years, and I’m curious whether the same fate has befallen their cutters.

author: msknight
author_rank: Regular Contributor
timestamp: January 22, 2024, 08:47:50 am
content: Quote from: tooki on January 22, 2024, 08:17:09 amUrk!

author: armandine2
author_rank: Frequent Contributor
timestamp: January 22, 2024, 02:01:55 pm
content: Quote from: tooki on January 22, 2024, 08:20:40 amNo obvious sign to me of anything amiss - it came greased and with a protective plastic tube over the cutter head.Don't know how the spring is arranged to open the jaws - but that seems to work ok, if lacking a bit of positivity.The packaging and brochure look good.Compared to my other small hand tools: Stahlwille flat needle nose, Lindström and Knipex side cutters, the Erem is fine.

author: tooki
author_rank: Super Contributor
timestamp: January 22, 2024, 06:41:20 pm
content: The spring is inside the joint in a milled space. I’ve opened Erem pliers many times, and it’s tricky to get back together. And DO NOT open it anywhere where little parts can get lost, as there is a little metal disc that acts as the opening stop; lose it and they will open too far.How is the alignment and precision of the cutting edges?

author: armandine2
author_rank: Frequent Contributor
timestamp: January 22, 2024, 07:43:26 pm
content: Tooki, I've just inspected the Erem jaws under the microscope and in comparison to the Lindstrom and Knipex I'd judge it second to the Lindstrom (whose jaws look perfectly matched).So perhaps you are on to something.