EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: Terabyte2007 on August 12, 2014, 07:05:26 pm
-
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.
-
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)?
-
How hot are you running it?
About 260-300C. A tad bit on the hotter side but not too excessive.
Remember, the hotter it is, the faster it will oxidize.
I just recently picked up a new pot capable of 537C. Although I don't run it that hot I wonder if the unit is running hotter than the thermo is reading.
Also, did you change the solder alloy used recently (maybe even inadvertently)?
No, pretty positive of that.
-
About 260-300C. A tad bit on the hotter side but not too excessive.
[snip]...I don't run it that hot I wonder if the unit is running hotter than the thermo is reading.
Assuming 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?
-
What we need is a great big melting pot! ;D
-
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.
-
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.
-
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.
-
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.
Interesting... Thanks for the info!
-
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.
-
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.
I 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.
-
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/ (http://www.pkaymetal.com/index.php/ms2-dross-eliminator/)
-
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/ (http://www.pkaymetal.com/index.php/ms2-dross-eliminator/)
Looks like a cool product. Watched a couple videos, thanks!