#97

does anyone have any tips or tricks for desoldering a potentiometer from a fates board? i cant seem to get all 4 or however many solder points loose at once and i feel like im damaging the board by holding it there so long. the desoldering braid i have is almost completely useless and i havent had much luck with my cheap solder sucker (just the kind that pulls back and then triggers). that worked for a pin header once, but that was kind of a different scenario it seems like

#98

Solder suckers can help, which one are you using… if you don’t have an Engineer SS-02 Solder Sucker, get one and try it… What you really want is an air reflow station to get that thing out…

Or you can try to use a larger iron tip to hold across the 3 pins to heat all 3 up at once and pull it out while they’re hot, it’s tricky but it can be done… I never solder the retaining clips on my pots for just this reason, just fold them over it’s good enough but if those are tacked down too it’s going to be a lot harder.

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#99

Are you trying to salvage the potentiometer to use again? If not, it’s easiest to cut the part away from the pins, so then you can desolder the pins individually.

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#100

im trying to take one from my old fates board that i fucked up elsewhere and then take off K2 from my current fates board very carefully and put the one i took of the old board onto the new board. im having a lot of jumpy encoder issues with that one

#101

this piece of garbage

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the ss-02 looks helpful. from what i remember, the reflow stations can be kind of expensive but im sure they’re worth it.

that’s a good tip, i’ll try that next time. wish i knew that before. thank you

#102

I find solder suckers are ok to remove most of the solder but usually won’t get you to the finish line. Do you have flux you can apply before desoldering with the braid? If not, try applying the iron to the braid to the joint and then some solder to that combo with the idea that that will seep through the braid and the braid can then soak up some of the joint solder. The braids are supposed to have flux on them but I find they always need a little help with flux applied to the joint or fresh solder (which is a tricky as obviously that solder will need to wicked away too but that solder will at least provide some flux for the old solder to join to). Ugly business.

Like @DMR mentioned, if you’re going to junk one encoder, definitely cut the encoder away from the soldered bits first.

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#103

i got a silicon solder sucker a while ago and it’s a gamechanger. way easier than braid or plastic solder suckers

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#104

A powered desoldering vacuum like the Hakko FR-301 is the best thing in my experience, but it is also way overkill (and $250-300) if you’re just using it occasionally. If you have a makerspace in your area you could try to see if they have one you could use for a 1-off job.

#105

How hot does your iron get? Big pieces like potentiometers act like heat sinks and it can be difficult to get the solder hot enough to use braid

Getting a variable temperature digital control iron was really big for me, you can do a lot of things so much quicker at the hotter temps

#106

A nice wick in a smaller size,1.5 or 2mm, has always worked well for me. Some nice flux if it’s giving you a hassle. Never found suckers to work on small things.

Depending on what iron you are using, if it is removable I would look for a knife tip. Pressing the edge flat against the wick on the joint spreads out the heat and works really well.

Gootwick
https://store.rossmanngroup.com/ab20-gootwick-cp2015-pink.html

This is only place I’ve found to get small quantities with fast cheap shipping. They have the 1.5mm as well. Useful to stock up. They also sell Amtech flux which is #1 for SMD stuff

Beware of knockoffs on eBay, got some fake Gootwick and it was rough to use! Also theres fake Amtech flux out there :sob::skull:

Good luck!

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#107

i guess 900° F/40 W. this one:
https://www.amazon.com/dp/B000AS28UC?ref_=pe_2640190_261118450_302_E_DDE_dt_1

it was a big improvement over my radioshack style piece of shit that was like the type that just has the power cord attached and no stand or heat adjustment. it made soldering go from impossible to very easy, but i think i got some bad solder or maybe my tip was bad for a little because when i soldered the trellis grids together for my diy grid, it was very weak and flaky. i dont think that had anything to do with the iron. i know its not the best option, but any other time it has seemed to work really well

it may not get to an ideal heat though, i have no idea how it compares to other irons. i have never gotten more than a tiny bit of solder stuck to the braid i bought

@alley_cam thanks for the link, i thinki will grab some, but that knife trick may work

@philmaguire i think that is what i need ultimately, thank you

@addamm i have tried that with the braid, but not with flux. i grabbed some paste flux from the hardware store, but i think that’s for like pipes or something. i was looking sort of recently online for a small amount of the liquid flux but im not sure which kind to get exactly

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#108

  • 40W is on the low side. it’s fine for small boards/repairs/projects. here’s a thing: wattage doesn’t exactly determine how hot the iron can get (900F is plenty hot), more how quickly it can heat up - this translates to temperature consistency when working with bigger parts / many parts in a row… or tasks like desoldering a big part.

  • it is probably not really temp-regulated, just a voltage conttrol. if you are gonna solder lots of stuff, it’s really worth $100 to get a regulated solder station - it will be easier and over time will likely save some parts from destruction.

  • if it really came with an enormous chisel tip, that’s not good for electronics. you want a chisel tip closer to, i dunno, 1/16" wide or something. (pointed tip is a little less useful.) this is the cheap and effective upgrade.

of course tools aren’t everything, and a simple tool will get the job done. practice is probably the main factor.

re: desoldering pots, it’s just hard. legs are already trimmed and will get messed up more. there’s a real risk of damaging traces. so “don’t do it” is pretty sound advice.

if you are gonna do it, a solder vacuum is a great tool. but it will amplify the risk of lifting pads. and like anything else it takes practice to get good at. also, they are not made equal. for some reason a thing called SOLDAPULLT appears to be universally well regarded. (it was the only usable one in our shop when i was growing up.)

as far as tips or tricks, all i’ve got is that it’s sometimes (counterintuitively) helpful to use large blobs of solder to hold heat. 1) it can actually make it easier to vacuum a leg. 2) you may be able to keep all the joints “wet” by going quickly around, and then just lift the part out. this technique is easier with two irons and a helper. in principle it’s the poor man’s solder pot.

2 Likes
#109

i use that narrow one on the right from this pack:

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i think you’re right. im not gonna worry about it for now. then get a better iron and a solder vacuum eventually. i appreciate the help.

also thank you for explaining the heat consistency. that makes sense

#110

cool. well if you have that whole pack it’s probably worth experimenting with the smaller flat tip, or the cone. you can get more surface area in contact with the part.

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#111

That might be the same iron I use (though it looks like there is a higher wattage one, too). I keep mine around 4, a little lower for smd and a little higher for pots, switches, etc.

For flux I use something similar to this though I don’t remember where I got it or the brand. If you get a flux pen just make sure you get “no-clean” and not “water soluble”

If you plan on doing a lot of projects it might be worth looking into using no clean solder for some parts and water soluble for others (though this is a separate conversation entirely!!).

One other thing - make sure your tip is clean when desoldering. If fresh solder doesn’t immediately stick then it’s not going to desolder. I recommend using one of those steel wool type cleaners over the wet sponge method but that’s up to you.

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#112

I’ve always wondered about this. I’ve been soldering then in my boards thinking the more there is the better for stress relief… But in these vertical pots and encoders, maybe not really helping? On the right angle DC power jacks, soldering the 3rd blade for stress seems essential, since plugging the cord in give lots of sideways force.

How do others feel about soldering retaining tabs on parts?

#113

One caveat, if your pots don’t use washers/nuts for security to a front panel of some kind I would advise to solder them down for security for sure, I’m mostly speaking as someone who pretty much is always fastening them to a front panel with washers/nuts.

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#114

Can anyone share what you do to clean the boards out of flux? Especially with loads of smd components like Mutable ones? I tried to use very soft brush + isopropyl alcohol which makes things better but still everything is kind a sticky and not fully cleaned.

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#115

I use a toothbrush with 99% iso and do a couple passes. If there aren’t any switches or pots on the board yet, I soak it in a little container and then scrub. If you have a nice nice PCB (Oshpark, etc) they can take a some action and be fine.

I recently had to shelve a Paia Fatman kit after months of work. Poor board took a beating. It was a pretty oldschool single sided board and pads were getting ripped left and right while trimming leads. I learned my lesson!

The dream would be to have an ultrasonic cleaner tho… one day!

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#117

Maybe I just need to try harder I am not sure, I use same things but either I use too much flux or I use wrong alcohol not sure but mines are always stay sticky, maybe need to be more patient in cleaning as well:)