Saving discarded solder for solder pot ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: April 12, 2018, 12:29:22 am
content: I have a metal scrub pad in a soup can for cleaning my iron, and its filling up with the used solder. If thats all dropped into a solder pot, do the contaminants separate from the pure solder so it can be used no problem ?

author: wraper
author_rank: Unknown
timestamp: April 12, 2018, 12:52:21 am
content: It's a crap full of dross, burned flux and other contamination. Quantity also should be tiny if you are not doing something insane.

author: Ian.M
author_rank: Super Contributor
timestamp: April 12, 2018, 01:02:22 am
content: It depends on what the solder pot is for - If you are using it ONLY for desoldering, and don't mind wasting a lot of time fluxing and skimming it outdoors or in a fume cupboard, no problem but otherwise you need to load it with good solder and as Blueskull points out, use an alloy that's compatible with your usual solder. Also beware of copper buildup in lead-free solder pots - if you cant justify dumping the pot regularly, you may want some pure tin or a low copper alloy in the same solder system for topping up to manage it.

author: lordvader88
author_rank: Frequent Contributor
timestamp: April 12, 2018, 01:10:28 am
content: Ok yeah it's not all 1 type of solder, but I'll set it aside rather than throw it out. I'll either make a little solder pot of buy a cheap one some day. It would make desoldering some scrapped PCBs easier.

author: gregariz
author_rank: Frequent Contributor
timestamp: April 12, 2018, 01:59:15 am
content: Quote from: lordvader88 on April 12, 2018, 01:10:28 amI used to use the bars in a pot when they were cheap for making fishing sinkers. If its all 60/40 if you have the dross reducing cubes you can throw some of that in. I usually find that it cleans things up a lot and then I skim off the scale.

author: TechieTX
author_rank: Contributor
timestamp: April 12, 2018, 02:37:16 am
content: If you're just looking at desoldering, peanut oil is cheaper and better thermal transfer than crummy old solder. Use an electric skillet and a thin layer (2 to 5 mm) of peanut oil... slowly bring it up to temperature. Do this OUTDOORS, or your whole house will stink of peanuts. Have a cover for the skillet handy in case you screw up and hit the flash point of the peanut oil. The smoke point is 231C, flash point is 315C. Once it hits desoldering temp, carefully lower the board into the pool of peanut oil, wait a few seconds until you see the solder melt, then remove it, quickly invert and rap it sharply to get the parts to fall off of the board. I used vice grips to hold the board tightly, and an old cake pan to knock the parts into. I've scrounged parts from boards this way before, and they all worked. Dish soap (surfactant) will help to remove any traces of peanut oil from the parts, followed by lots of distilled / de-ionized water.We used a thin layer of peanut oil on top of the solder tank in a commercial wave soldering machine back in the '70s, and it worked fine until someone drained the solder tank one day and then forgot to turn off the heater. D'oh! The peanut oil didn't burn, but it produced HUGE freaking clouds of smoke, so we had to evacuate. Don't follow our example, OK?Basic safety precautions are a good idea: elbow-length gloves, splash-proof goggles or a face shield, NO synthetic clothing (cotton only, or a rubber apron). I never got burned, but I came close when I slipped once and dropped the board back into the skillet. If you get hot peanut oil on your skin it WILL leave a nasty burn that will take many months to heal, if ever.Note: I've actually *done* this, and can verify it works. I'm not some drone parroting something they'd read on a blog, somewhere. I used an ugly old skillet I'd bought at a yard sale for a few dollars and some premium peanut oil. A friend later used that same skillet for SOLDERING through-hole boards with a dip-solder method, and it worked. He made several hundred boards that way with tin/lead solder. You'll have to get it hotter with lead-free solder, of course, and the peanut oil will undoubtedly start to smoke. Keep it below the flash point and you'll be fine. Wish I had some photos to show you, but that was back in the days of film cameras, and I didn't keep any photos.