COWW+2% Tin formula ?

Walks

Active Member
I've read in several Websites that a lot use an alloy of COWW plus 2% Tin added for most medium loads.
I wanna make sure I have formula down.
20lbs COWW, divided by 16 ounces equals 320
Ounces. Which is then divided by 2%.
That equals 6.4 ounces of Tin.

Is that formula right ?

Thanks Guys
 

Rick

Moderator
Staff member
I weigh the ingots going into the pot on a digital postal scale in ounces, then use a calculator to determine how many ounces of Sn at 2%. Can't get any more simple or easier than that.
 

Rick

Moderator
Staff member
Ok, long form. Weigh ingots, scale says 6 pounds 4 ounces. Multiply 6 (pounds) times 16 (ounces in a pound), that comes to 96 ounces. Now add in the additional 4 four ounces and you have 100 ounces of alloy. Use the calculator to determine how many ounces 2% of 100 is, weigh out that many ounces of Sn. Add Sn to pot.
 

Walks

Active Member
I weigh all ingots ahead of time and write the of #pounds&ounces on each one. Add them up to make 50lbs, the (comfortable) size of my alloy mixing pot.

It was so easy when I had 1lb tin bars and 5lb pure lead ingots.

Or I got stuff from old Mr. Art Green.

I just have never made up COWW+2% Tin.
Just wanna give it a try.
 

oscarflytyer

Well-Known Member
not sure I can post it here, but I have a ready made (not by me/from the 'other site' iirc; used it for years now) Xcel sheet that has all the formulas worked out. Just plug in variables. Happy to email it if you want to PM me.
 

fiver

Well-Known Member
I'd try 1% first most ww's already have .5% tin in them.
well they used to.
if you got newer-like-90's on forward newer ww's,,, who knows?
about all you do know is they have about 2-2.5% antimony and maybe a trace of arsenic.