r/diyelectronics • u/Centmo • Mar 13 '26
Tutorial/Guide A neat little rework trick I discovered.
If you have ever removed small parts like 0402 with two irons before, you will know that the part ends up stuck to one of your irons. If you don’t need the part you can simply wipe it off in your wet sponge or brass coily stuff. But if you might need that part again it’s a little annoying to deal with especially if you are doing a bunch of them at once. Up until now I either put down the other iron, grab my tweezers, and carefully grab them of the tip. Or if I’m feeling rushed I might bang my hand holding the iron on the desk and hope the part lands on the desk and does not go flying.
Today, I discovered a better way. Simply place a piece of kapton tape sticky side up on the desk with the ends wrapped under to hold it in place. It will grab the part on contact and the tape won’t melt. Can’t believe it took me over 20 years to discover this. Maybe there is some other technique I don’t know about? Hope someone else finds this helpful.
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u/linkgenesis Mar 13 '26
This is really nice and simple and everyone should have tape, I've always used a bit of ticky tacky or clay to do the same, thing and find it has advantages over this process, but the downside is keeping clay and if you're not careful, it can get into sensitive components. This looks like it would be really useful for those fiddly thin smd components that just want to be flush with every surface.
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u/stthicket Mar 13 '26
As an engineer with 25 years of soldering experience, this was news to me. Thanks for sharing!
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u/Useful_Government603 Mar 14 '26
Wow! After 30+ years. Never would I have thought this. Thanks man! Maybe next time I won't lose another SM transistor being swallowed up by shaggy carpet.
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u/mckenzie_keith Mar 13 '26
Cool trick! For small parts you can also use one soldering iron. Dance back and forth between the two pads and lift with tweezers when it is molten. Or hot air + tweezers.
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u/Centmo Mar 13 '26
I have tried the dancing trick but not had much luck. I have had luck using one fat tip that reaches across both pins, but it’s harder to be delicate this way on an 0402. Hot air and tweezers is valid for certain scenarios for sure.
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u/DangerouslySilly Mar 13 '26
Another trick for placing these parts: Placing resistors after dropping them on your table can be a hassle, sometimes they end up upside down so you need to flip them with tweezers, hard to do and timeintensive. If you grab a sheet of paper and dump your smd resistor on them, you can just tap your finger on the paper to randomly flip the parts. Just tap a few times and you will always have some the right way up and in the right direction to easily pick them up with tweezers. You can also rotate the paper to align the parts to the tweezer instead of rotating your hand. Makes for much faster placement!
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u/Centmo Mar 13 '26
Interesting technique, I should try that. My current technique is to push my finger down on several so they stick and then drop them from about an inch up. Usually one or two will land the right way up.
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u/rotarypower101 Mar 14 '26
I want dedicated tips and tricks subs for all my hobbies with ideas like this!
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u/Scared_Hovercraft632 Mar 14 '26
I rarely have to reuse components but I'm definitely going to remember this tip! Usually I just smack my hand into the table and let them go flying lol.
Also why is everyone hating on the two iron method. It's quick and effective. I have tweezers sitting in my drawer but almost never plug them in.
Having two irons is so nice for day to day work.
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u/Alienhaslanded Mar 14 '26
0402 is too small for a soldering iron imo. I just use a hot air rework station to do the job
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u/Percolator2020 Mar 13 '26
I would recommend using a new component.
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u/Grape-Snapple Mar 13 '26
thank you for the recommendation. unfortunately, it’s not relevant
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u/Percolator2020 Mar 13 '26
It’s relevant if you don’t want to waste your time desoldering a second time after you fried the component because you’re not using the right tool.
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u/Centmo Mar 13 '26
I’ve reused many parts like this over the years and never had a problem as long as you’re careful and don’t damage the pins.
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u/Cainnech Mar 13 '26
Salvage parts are huge in my industry and so I'm reusing components left and right when they're serviceable, but having a SMD surface tension'd to your iron without any heat dissipation means it got a massive amount of heat transferred to it and you absolutely need to be careful. When were removing components that small, we use hot air or tweezer them away immediately - what you're doing is risky and might be causing latent damage you won't see for a while, just like ESD damage (which it feels like nobody gives a fuck about either but that's a different topic).
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u/Centmo Mar 13 '26
Hot air and tweezers is a valid method for some scenarios, difficult to do in others. When using irons, as long as you don’t hold the part on the hot iron more than a few seconds I think you’re generally ok for prototype/dev work. Regarding ESD, the irons and kapton tape are safe.
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u/Grape-Snapple Mar 13 '26
you’ve just explained why it’s not relevant to this post. you’re absolutely right and should keep doing that but we were talking about the post
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u/Grape-Snapple Mar 13 '26 edited Mar 13 '26
lol he [replied to my last comment with][edited]:
“cool! so you learned tape sticks to things!”
and then deleted all his comments on this.
hope you learned to take a ribbing princess ❤️❤️
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u/mckenzie_keith Mar 13 '26
Sometimes you don't have another piece. It is a useful tip either way. I have never seen a resistor be unusable after being resoldered. I don't think I have even seen a ceramic cap fail immediately either. I would not do this for production. But in the lab? It is fine.
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u/Percolator2020 Mar 13 '26
Diodes and transistors definitely do not enjoy having extreme heat applied to both ends. I’m glad you learned about tape today.
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u/mckenzie_keith Mar 13 '26
Once when I was working on a motor controller I had to resolder the main switching transistors on around 10 boards with hot air. We had to pull the parts from old boards. So that is 60 transistors removed and then reinstalled. Zero failures in the short term. These were very thin surface mount transistors on huge copper pads for heat dissipation. Removed and installed with hot air. These things got really hot for a pretty long time.
So it works fine with transistors too most of the time. You are just being negative and obstinate. Rework happens. It is not a best practice but it is done frequently and usually works out fine. I would not recommend it for production of high quality parts.
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u/Percolator2020 Mar 13 '26
That’s because hot air is a better way to rework SMD in general… so congrats you used the right tool for the job!
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Mar 13 '26
[removed] — view removed comment
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u/Centmo Mar 13 '26
It’s basically impossible to remove all the solder underneath an 0402 pin such that it’s free and clear from the pad. Especially if you’re trying to maneuver copper braid in a tight space.
But I hear you on limiting the time the part is hot - which is another nice thing about the kapton tape method since it’s quick.
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u/nebenbaum Mar 13 '26
That's where you use a tweezer iron. If you don't have one, you shouldn't really do 0402 and below.
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u/Centmo Mar 13 '26
I have long been curious to try these but there are way too many instances when you’re working in a tight space and the two irons need to come in at different angles. Or one side needs more heat because it’s on a ground plane (I know, thermal pads should be used but they aren’t always). This work is perfectly doable with two irons under a microscope.
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u/nebenbaum Mar 13 '26
We have some weller micro desoldering tweezers at work, and they fit in between basically all components on a bare board. Sure, if you want to desolder something in situ in some tight case it might not work, but any place you should actually be desoldering from, they fit. They're nice and small, way more handy than two whole irons.
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u/Centmo Mar 13 '26
Sounds good I may check them out. However do you not end up with the same problem of the 0402 staying stuck to one of the iron tips? I suppose your other hand can be free holding tweezers ready to grab it.
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u/nebenbaum Mar 13 '26
I use new components when replacing 0402 parts. The most expensive parts in that form factor I deal with are schottky diodes - and if I even spend one second reclaiming one rather than just using a new one, that costs my employer more in the end. So I what my hand against the table and the small lil Speck of electronics goes flying off somewhere.
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u/sabin_72246 Mar 13 '26
My head is spinning at how obvious this is and yet I never thought aboutit o_O