solder questions

[buggybuilder]

Been doing a little cleaning and found some rolls of solder. One roll is 50/50 lead-tin. The other is an acid core 40/60
tin/lead. Is one of these better for plumbing and the other on for electrical work?
Thanks for any help.

[RickinTN]

From what I understand solder with any lead in it is a no-no for plumbing. That is why we see lead-free solder today. I can't help on the electrical part although I would think either would work.
Rick

[garandsrus]

You should not use the acid core for electrical. It will cause corrosion. Neither for plumbing, as was mentioned.

[MT Gianni]

50-50 was the standard for plumbing until the late 90's when lead was banned for potable water use. It is great for casting. I would melt the acid core in a throw away container and cook the flux off of it. Get a junk pan from a thrift shop, avoid aluminum, or a teflon fry pan that has had the finish shredded. Note however, I am a rednecked innovator the safety dept kept their eyes on.

[bangerjim]

Use it for casting. either one will go good in a mix you calculate with the hardness calculator on here. But be VERY careful re-melting acid core!!!!!!!! Treat it as "WET" Pb......it will summon the tinsel fairy very easily!!!!!!! Melt small lengths in a COVERED pot, wear welder's gloves and a face shield. Or just forget the acid core stuff. Pb solder is NOT used in modern plumbing, so what you have should only be used for casting. Acid core is NEVER used around electronics!!!!!!!

banger

[JonB_in_Glencoe]

Both will work for automotive purposes (except electrical).

50/50 lead-tin (no flux I assume?) for auto-body

acid core 40/60 for Radiator repair.

I wouldn't use either for household "plumbing or electrical work"

[JonB_in_Glencoe]

Hint: When I've smelted acid core solder for boolit casting purposes, I add plenty of sawdust just as the acid starts cooking off, the saw dust absorbs some/most of the acid and you can scoop it out easy and don't need to "cook" it off...because it does take a while to cook it off...ask me how I know

[Scrounge]

50-50 was the standard for plumbing until the late 90's when lead was banned for potable water use. It is great for casting. I would melt the acid core in a throw away container and cook the flux off of it. Get a junk pan from a thrift shop, avoid aluminum, or a teflon fry pan that has had the finish shredded. Note however, I am a rednecked innovator the safety dept kept their eyes on.

the flux is usually sal ammoniac in acid core solder. You should be able to just wash it off with hot water once it's melted out of the solder. I'd start a pot with something else lead melted in it, and slowly feed the acid core solder in, and wear a full-face shield. Work outdoors, too. Gonna be at it for a while. Once done you should have some really clean ingots.

[MaryB]

Neither is good for electronics... 63/37 is a common electronic solder(rosin core!) as are lead free solders for some specialized applications where tin whiskers can form...

[Winger Ed.]

The 50/50 should still be legal to use for copper drain/sewer lines, but not water.

Its also the right thing to use for auto. body work.
That's what they had before 'Bondo' came along in the late 50's.
Hence the term 'Lead Sled' for cars that had been dented, and worked on a lot..

[bangerjim]

the flux is usually sal ammoniac in acid core solder. You should be able to just wash it off with hot water once it's melted out of the solder. I'd start a pot with something else lead melted in it, and slowly feed the acid core solder in, and wear a full-face shield. Work outdoors, too. Gonna be at it for a while. Once done you should have some really clean ingots.

I have two 10# rolls of old "ACID" core and believe me it is NOT filled with sal. It is H2SO4 and is a liquid-gel format. nasty stuff. You have to crimp the end when you are done or the stuff will ooze out and eat anything it comes in contact with. Especially you skin. Back in "the day", industry did not care a hoot about personal safety!

Just test your acid core B4 trying to re-melt it. If I were you I would just leave it alone....for personal safety reasons. After all, how desperate can you be for a mere few pounds of casting Pb?

That's my educated opinion. Be safe!
banger

[NyFirefighter357]

Leaded solder can still be used in most states for all non-potable water applications such as waste lines and heating as well as auto body if you can find someone who knows how to lead a body.

Acid core solder is usually used for joining sheet metal, gutters ect. It can be used on copper but there are much better fluxes these days. Anything acid core solder is used on needs to be cleaned thoroughly as any residue will cause rust/corrosion.

I have something like 200lbs of different solders. You can old tell acid core by the way the end of the solder is so corroded.

I've thought about neutralizing the acid upon melting with baking soda or borax.