Acid core solder??

[baogongmeo]

Has anyone had first hand experience using acid core solder to add tin? Big no-no or good to go? Can one smelt it to cook the flux out then cast into 1-2oz slugs?
I keep finding rolls of acid core priced cheap.

[Pipefitter]

Keep it out of your casting pot, it will do nasty things to the metal of the pot. Stand upwind when you do melt it. Rosin core solder is not too bad for the pot or the melt.

[baogongmeo]

What about radiator shop drippings? Usable if smelted first?

[JASON4X4]

Smelt and clean any type of solder and you will be good to go

[odinohi]

What about radiator shop drippings? Usable if smelted first?

yes. A pain to smelt though

[alamogunr]

I've got a bunch of it and it probably will still be in my stash when they carry me off in a box. I tried to melt it down into ingots several years ago. There was enough acid flux in the pot that I couldn't ladle the melt into ingots without carrying a lot of the flux with it. It coated the inside of the dutch oven and was a bear to clean up.

I guess you could throw a pound into a large pot of WW and not have to do any additional fluxing. I've gotten too old to mess with WW so I don't intend to find out.

I wouldn't try to add tin to my casting pot by cutting lengths of acid core solder w/dikes. The acid flux leaks out of the end. I suppose you could cut lengths and hang them to let the acid run out but then the fluxing advantage would be diminished if not lost. Who knows? That might be an advantage that I didn't think of.

I occasionally give a roll or two away to locals that need to solder non-electrical items. I guess if I advertised, I could get rid of it faster.

[baogongmeo]

Why do you say that radiator shop drippings are a pain to smelt? I can't imagine that they would be worse than COWWs with all of the clips and what ever else all the dross contains.

What about flux when smelting drippings? Wax or sawdust? What about acid core fluxing?

Oh, and many thanks for the advice and information guys.

[40-82 hiker]

It is useable for sure. Smelt it in your "smelting pot", letting the acid core rise to the surface. Don't let it get too hot! Then, cover the top of the molten solder with a thick blanket of sawdust to absorb the flux. Scoop off the sawdust and put it in a coffee can or such, and flux again as before. The idea with the first flux with sawdust is to simply absorb the acid-flux, and not burn the sawdust as a normal fluxing procedure would require. After several fluxes with sawdust there will be no hint of acid-flux left. Make your ingots, and scrub you smelting pot with baking soda and water thoroughly.

Wear face protection throughout the process, and try not to breathe vapors. I wore a respirator when smelting a batch a couple of years ago, and all went well. It is easy and using precautions you will have some useable ingots. The acid is in the flux, and will not be in the ingots. Others on this forum told me how to do it back then. Search "Castboolits" and you might find more info. Good luck.

[LAGS]

Most of th old Acid Core Solder is 60 / 40 mix
60 % lead and 40% tin.
Works great if blended in the proper ratios with more lead, Or like I use to do.
Just blend it, one pound of 60/40 solder to 18 1/2 pounds of COWW and you end up with around 20 lb of a 96/2/4 blend
96% lead, 2% tin and 4% Antimony

[JSnover]

Yuck! Melt it in another pot if you must. The fumes are nasty (probably toxic!). I tried it once.

[too many things]

have you seen the molds that are pitted? You can not get acid out of lead
if you want to use it make sure you clean the molds very good

[alamogunr]

Thanks, 40-82 hiker(I have no idea what that refers to), for pointing out a way to mitigate the acid flux. It was so long ago that I tried to make ingots from acid core solder, well before learning that sawdust was a good flux, that I never connected it as a way to get rid of the acid. I have so much solid solder that I don't need to use the acid core, so I'll save it for others who can use it as solder.

I kept hoping that this board would refer to solder the same way industry does(did) as a ratio of tin/lead. Then I realized that tin/lead solders are fast becoming a thing of the past, so I guess it doesn't really matter. Just to be sure that I wasn't whistling Dixie, I went to the shop to check the boxes of solder I have. All TIN/LEAD. But, again, it doesn't really matter.

[LAGS]

The Fumes are Nasty, but with good ventalation it is not an issue.
I worked several places years ago and we used the Acid core solder to solder parts together and there was never an issue with the acid in the solder continuing to be active after melted.
Melt the solder in an old pot and cast them into Ingots.
Then drop the ingots into a mixture of Baking Soda, and water.
If it foams up on the surface then there was still acid ON the Lead not IN it.
But now it will be Netrulized.
Dry the ingots, and then remelt them and try it again.
I bet there will be no Foaming or bubbles in the water.

[40-82 hiker]

Dry the ingots, and then remelt them and try it again.
I bet there will be no Foaming or bubbles in the water.

I actually dunked a few ingots into my baking soda water before I used it to clean my pot and I did not get any bubbles. None. In fact, when I cleaned my smelting pot I did not get any bubbles either. No acid!

[AllanD]

I've made it a habit to add some sodium carbonate to my "smelting" melts,

But I also clean my melting pots with Hydrochloric Acid

I also clean any used molds with Hydrochloric acid

And FWIW I came up in the military electronics industry, I always refer to solder by it's Sn content and from my experience most Acid-core plumbing solder, at least that which I've seen, had been SN50 (typically labeled 50/50 tin/lead)

As an additional note, Hydrochloric Acid is commonly used to remove rust from iron and steel...


Want to take dirty iron back to bare metal?

[baogongmeo]

I've made it a habit to add some sodium carbonate to my "smelting" melts,

But I also clean my melting pots with Hydrochloric Acid

I also clean any used molds with Hydrochloric acid

And FWIW I came up in the military electronics industry, I always refer to solder by it's Sn content and from my experience most Acid-core plumbing solder, at least that which I've seen, had been SN50 (typically labeled 50/50 tin/lead)

As an additional note, Hydrochloric Acid is commonly used to remove rust from iron and steel...


Want to take dirty iron back to bare metal?

AllanD,
Please a lttle more info on adding sodium carbonate to your smelt and cleaning your melting pots with hydrochloric acid.

Thanks everybody for sharing what you know...this is a great website!

[GaryN]

I melted down about fifteen pounds of it once. It works just like any other solder of the same alloy when you are done. When melting it down, do it outside and be upwind. That stuff is toxic. Also don't try it in the suburbs. Your neighbors will hate you. It helps to use sawdust for flux and to sop up the acid. I would buy it again if the price was right. Don't melt it down in your casting pot. Use an old cast iron pan or something else. It will ruin your casting pot.