Solder Pot Question - Page 1
Forum section: electronics / general

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: August 12, 2014, 07:05:26 pm
content: I have a rather large solder pot and currently, there is about 4lbs of 99.99% pure Kester solder in it. I seem to be getting more than usual surface oxidation that I have to keep skimming off almost constantly during use. I know there will be some, but this seems exessive. The solder is fresh, only been used a couple times. Is there a way to reduce the oxidation layer by using an additive? Or any other tip would be welcome.

author: nanofrog
author_rank: Super Contributor
timestamp: August 12, 2014, 10:48:37 pm
content: How hot are you running it?Remember, the hotter it is, the faster it will oxidize.Also, did you change the solder alloy used recently (maybe even inadvertently)?

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: August 13, 2014, 12:17:18 am
content: Quote from: nanofrog on August 12, 2014, 10:48:37 pmQuote from: nanofrog on August 12, 2014, 10:48:37 pmQuote from: nanofrog on August 12, 2014, 10:48:37 pm

author: nanofrog
author_rank: Super Contributor
timestamp: August 13, 2014, 03:14:55 am
content: Quote from: Terabyte2007 on August 13, 2014, 12:17:18 amAssuming this is a Chinese made unit (not a big name brand), running a fair bit hotter than it's set for certainly seems within the realm of possibilities IMHO.Do you have a way to check?

author: vk6zgo
author_rank: Super Contributor
timestamp: August 13, 2014, 06:33:29 am
content: What we need is a great big melting pot!

author: Psi
author_rank: Super Contributor
timestamp: August 13, 2014, 06:38:01 am
content: If its a big pot of solder it will have massive thermal mass. Surely you can run it at a lower temp than 260-300C.It only needs to be molten and solder melts just under 200C or just over for lead free, maybe try 220C.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: August 13, 2014, 11:15:46 am
content: I think I am going to set aside a bit of time this weekend and check the actual temp with a 1kC thermocouple I have to see what temp this thing is really running at. Then I can calibrate the unit to Kesters specifications. Nanofrog, you may be right on the variance for a chinese made unit.

author: Stray Electron
author_rank: Super Contributor
timestamp: August 14, 2014, 03:53:35 pm
content: I've never used it in a solder pot but when casting lead bullets I add some bee's wax to the mix. (A couple of pieces about the size of a pea for a 10# pot. Add more as it burns off.) It melts and floats on top and helps prevent oxidation and also acts as a dross to help collect and separate any impurities in the lead/tin/antimony mix. I think bee's wax was the main ingredient in the old organic fluxes used in solder and I don't think it will harm your electronics but you need to test it before using on anything valuable. Bee's wax works fine at lower temperatures but starts to smoke and burn off quickly at higher temperatures. They also make synthetic fluxes for bullet casting that work better at higher temperatures but I don't know what's in them or how safe they'd be for electronics.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: August 14, 2014, 04:30:27 pm
content: Quote from: Stray Electron on August 14, 2014, 03:53:35 pmInteresting... Thanks for the info!

author: wraper
author_rank: Unknown
timestamp: August 14, 2014, 04:39:22 pm
content: Don't think that a bee wax is a good idea. When you are casting something you don't care what will be on the top. When soldering it is completely opposite. All that bee wax will end up being on the board. Don't know if it will prevent soldering, but all board including holes will be coated with that crap. And it wont be like you will be able to easily clean it from the PCB bottom, and likely impossible from the holes.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: August 14, 2014, 05:40:33 pm
content: Quote from: wraper on August 14, 2014, 04:39:22 pmI don't think I will use bees wax, I thought it was interesting because I never heard of it before. I think the best method I have come up with is to use UltraPure Kester, Skim regularly and run the heat just a smidge above the melting point to prevent any cooling. Other than that, not sure what else I can do.

author: David Hess
author_rank: Super Contributor
timestamp: August 14, 2014, 06:06:51 pm
content: Maybe something like powdered ammonium chloride would help? It looks like they make reducing agents to turn the tin oxide back into tin:http://www.pkaymetal.com/index.php/ms2-dross-eliminator/

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: August 14, 2014, 06:16:35 pm
content: Quote from: David Hess on August 14, 2014, 06:06:51 pmLooks like a cool product. Watched a couple videos, thanks!