Best method for soldering to bottom of pots...

[Norrin Radd]

Anyone got some good tips on soldering to the bottom side of potentiometers? I do just fine with all the other soldering bits but when it comes to attaching wires to the bottom of pots, it's always hit and miss (think I've fried a couple pots, too). Looking for some advice or tips and tricks to make that part go smoothly. I've got an adjustable temperature iron and decent basic skills.

Thanks!

 

[unfamous]

Flux and tin the bottom of the pot, tin the wire, place wire and just enough heat to melt the solder. No other trick needed

 

[guitarbuilder]

I struggled with this with my low watt soldering pencil and its conical point for 20 years. I could usually make it work but it looked like a meteorite. I finally went to Walmart and got a higher wattage gun and that solved the problem. Clean the back of the pot to remove any oxidation first too. I use a 60/40 solder from Kester. You don't want to overheat the pot. Guys will tell you you can do it with a low watt pencil....good luck with that.


https://www.walmart.com/ip/Weller-7200PKS-KIT-SOLDER-GUN-75W-SENSORMATIC/46651073


https://www.amazon.com/dp/B00068IJPO/?tag=tdpri-20

 

[Chunkocaster]

I crank the heat up and drop solder on the pot after scraping it back first.
Then tin the wired and solder it on.
I struggled with a low wattage iron. I bought a cheap temp adjustable 2 in 1 soldering station and it makes life easy. The heat gun is great for heat shrinking wires too.

 

[Dennyf]

Get a round crimp- on terminal lug that fits around the pot shaft (I forget the size, sorry). Crimp/ solder all your grounds to the lug, then slip it over the pot shaft before you install it.

 

[8barlouie]

It’s a lot like cooking steak. If you cook over low heat, the steak will cook evenly all the way through. Not good if you’re wanting medium rare with a nice sear. To do that, you want high heat so the outside gets nice and carmelized but it stays cool in the middle.

With a low wattage iron, the heat has time to spread throughout the pot. By the time it’s hot enough to solder a wire to the top, the temp inside has exceeded the limit. You need a nice hot iron to get the surface hot enough without melting the inside.

40 watts minimum is my comfort zone.

 

[Teleterr]

Why the hell aren't there ground lugs on the pots ? Idiots are out there solving non-existent problems , see threads on bizarre new tech, while here there's a simple solution to a hassle that doesn't need to be.
While in Europe in the 60s, all the pots I bought for my electronic projects had them. I guess the designers don't use their product.

 

[Wallaby]

You need to be able to heat the area to be soldered faster than the heat will spread in the metal. I use a Hakko for this, it's a way better tool than I need or deserve, but the temperature adjustment makes hard things easy for me.

Aside from that - great advice earlier in the thread - clean it, flux it, tin everything, solder it on quickly and remove heat. Watch it turn shiny, clean off the residues.

Keep the flux area on the pot as small as possible, smaller than you think.

Practice helps too.

 

[viking]

Its real easy to bend the small tabs and remove the pot case. No risk of getting too much heat on the pot innards.Get the solder on the casing , assemble pot again , use a second of heat to secure the wire(s)

 

[Blue Bill]

I sometimes use a small slot screwdriver to hold the wire securely to the pot can, while heating the solder. It maintains contact between the wire and the can.

 

[FenderGuy53]

Flux and tin the bottom of the pot, tin the wire, place wire and just enough heat to melt the solder.

^^^ THIS ^^^

 

[lammie200]

Yeah that and a lot of times I create a grounding strap so that I only solder to the back of the pot only once with the strap. Then I solder all the other grounds to the strap. A piece of hard wire works well for the grounding strap. You just have to make sure that it doesn't contact anything else when you push the controls into the cavity. This particularly works well with a bridge ground wire.

 

[rze99]

I scrape the back of the pot with a sharp screwdriver to rough up a patch and provide a key. Seems to help get a first shot fix. High power solder iron helps too. I first put on a blob of solder on the pot where I have scratched it and then put the wires into that blob.

 

[Fatcat211]

I echo most of above. Use a file or Dremel to sand the spot where you are going to solder. Then tin that spot. You’d be amazed how much easier it makes the job.

 

[schmee]

Use some flux on the pot. I like NoKoRode, Heat the pot and drop solder on making a glob. You may need to brush, Dremel or scrape it first if the pot looks too shiny or has that goldish color.. (Alpha, Bournes etc) CTS solder fine without scraping.
Then tin the wire and heat the glob on the pot and lay the wire into it.
40 watt works fine for me.

 

[dogmeat]

sand off the spot, be sure the tip is clean. let the tip come to maximum temp, tin it, etc... then put it on the pot sideways for maximum contact and shove some solder on it (the tip) - I know, you're not supposed to do that but the melted solder flows down onto the pot and increases the contact for better heat transfer. as soon as you see it flow on the pot, pull the heat off and let it cool off some. then run a button of solder to make a good spot to tie your grounds. even a pinpoint tip has enough heat if you can actually use it

 

[greasamizer]

Every answer here has merit. There are a lot of guys with a lot of knowledge-never ever a bad thing! In my case, I 'wash' the back of the pot with lacquer thinner, etc.; then take a brass-bristled brush and clean the crud off, then wipe again. You have a nice shiny rear (of the pot). take some GOOD rosin cord flux and coat the area to be tinned. Then, like everyone here says, "tin" the back; I try to get a nice little blob of solder on it, then tin the wires; put said wires onto the pot, then heat up the whole until you see it all melt together. When done, checking for zero resistance wouldn't hurt.

 

[MrHamburger]

Good soldering iron, with adjustable power supply, a nice fat soldering tip and scratch up the bottom of the pot with an exacto, razor blade, car key, etc.
get your blob on there and dip the wire into the blob.
Those pencil thin tips are garbage. I do electronics assembly for work. I use the chisel-looking tips for everything, even smt stuff. A nice fat tip will get the area heated quicker without heating up everything around it.
I never use flux, it makes a huge mess, excessive smoke and can create bridges on circuits.
Most standard solder already contains flux.

 

[MrHamburger]

Also, please don’t tie wires to solder lugs on pots and switches. I don’t know why people do this. It makes it extremely difficult to remove them later.
I spent way too much time rewiring a Tele a few weeks back having to apply heat while trying to untangle leads. It’s completely unnecessary. End of rant.

 

[24 track]

take a Qtip , soak it in lighter fluid and wipe the bottom of the pot to remove any oils or grease, ,then take some 800 grit sand paper , just a bit and scratch the bottom of the pot at the point you want to solder, just to rough up the surface clean again with Naptha ( lighter fluid) add flux and use a a really hot soldering Iron for a fast hot hit ,
Get in Get out and you will not damage the pot unless you hold the iron to the pot for an extended period , also pre-tin the wires before soldering.

For Chassis grounds and pots I use a 60watt iron for a really hot hit