Three Sided Solder. What Alloy?

[pete501]

This looks to me like some form of solder. It is unmarked, I have two different diameters, the one pictured and one slightly larger. Does anyone know the make up of this alloy.

Yes I know that a member here will test samples. The scrap yard can test it for me but the last 3 times the man who is authorized to test samples has been busy.

[RogerDat]

The three sided form is one I have seen called tri-bar and it was in many different tin/lead ratios. So the form I think isn't indicative of the alloy. Is there nothing at all stamped anyplace on the bars?

My first hunch is radiator or body solder, but those can have different alloy ratios depending on tinning or filling body solder for example.

[Kraschenbirn]

I've got some 'wiping solder' (63/37) that appears very similar to yours but mine is stamped "Bell System" with the old Bell Telephone logo.

Bill

[pete501]

There are no markings on both lots.

[marek313]

I pull any solder that i find at my scrap yard so I have some of those rods as well but i never figured out the tin content. I found many 50/50 bars but these thin ones have no markings. I figured it had to be worth at least $1/lb so I grab any solder I find there.

[RogerDat]

Rotometals shows that tri-bar in a wide range of tin:lead ratios.
https://www.rotometals.com/solder/

If you are buying it as scrap lead at scrap lead prices you sure won't lose anything on that deal even at 10 or 20 percent tin.

Best bet is to put 2# of COWW lead and a pea sized piece from the two batches of solder in a SFRB and send it to member BNE. It does sort of depend on how much you have, figure the shipping and 2# of lead are about $9 in order to know what you have. If you have just a few pounds not really worth the additional cost. I always try to save up until I have about 5 things to test so I get the most for my shipping cost.

You can just set the unknown bars aside as mystery solder. If you hit garage sales, flea markets and scrap yards over time you will probably accumulate partial solder rolls with unreadable labels, bars or ends of rolls that are clearly solder but without markings, maybe even some odd bits and pieces of pewter, solder joints from lead pipes etc. Get a big enough collection and just melt it into one big batch. Get a sample of that batch tested. The batch being larger makes the shipping cost more worthwhile. I have done that a few times. Typically come out between 23 and 43 percent tin. Did hit 62 percent once but had some small picture frames I was sure were pewter but wasn't stamped that I could see.

[Harry O]

I get (from my wife) miscellaneous rolls of solder that she finds at estate sales cheap. Most of the old ones don't have any markings. I melt them down, get rid of the rosin core (do it outside), and cast them into 0.690" balls. By knowing the weight of a pure lead 0.690" ball and a pure tin 0.690" ball, I can calculate how much tin is in the ball I cast. It usually runs about 35% to 40%. Solder in the past had a lot less tin in it than most of it has now.