tin to lead ratio question

[perimedik]

I have been surfing the forum and checking various, what seem to be, reputable sources for an answer.

Where to begin.
I will be suing a 10lb Lee perfect production pot with spout to cast 30/30 bullets into a Lee 150gr FN GC mold.

I have Ingots I have been melted down from fluxed clip on wheel weights.
I have some 50/50 bar solder. (could I use lead free wire solder?)

I have seen suggested 1lb of tin solder for every 9lbs of lead (wheel weights).
I have seen 1/4 oz for every lb of lead.
I have seen ratios inbetween

I know a hardness test is really going to give me the answer I am looking for.
Is there a place for a good answer (reference manual etc)
I do not want to melt 10lbs - cast and quench - only to find out the batch is too soft, to hard, flows pooly due to mix.
I do realize it is trial and error. I do understand there really is no EXACT formula.
I guess what I am looking for is a reasoble start point that is not wasteful (time, resources, lead, tin).

So what would be the correct start point for 10lbs batch ratio?
Thanks

[geargnasher]

Short answer, two ounces of lead free OR four ounces (1/4 lb) 50/50 solder per ten pounds of clip-on wheel weights will be plenty. That will give you a 1.5-2% total tin content with the tin that is already in the WW.

No need to add more than 2% tin ever in my book, all it does is aid castability (ONLY if you keep your alloy well below 750 degrees), and bind with the antimony to give the alloy more malleability, toughness, and help prevent "antimony wash" from forming in the barrel.

Tin doesn't add a very significant measure of hardness, in fact you'll be hard-pressed to tell if 1.5% made more than one point of BHN difference with wheel weights.

If you don't have a Lyman Cast Bullet Handbook #3, get one, it has lots of good data on alloys.

If you air cool this alloy, and I'm presuming you separated the clip-on wheel weights from the softer stick-ons, it will be about 13-15 bhn when air cooled and aged for a couple of weeks. If it's a mix of clip/stick weights, it will be softer depending on the proportions. If you water-quench it or oven heat treat it, you can get 22-28 bhn, but you will be just fine shooting them air-cooled, sized, lubed, and gas-checked in your .30-30 up to at least 2k fps.

Gear

[lwknight]

If your bullets perform well on the game then by all means don't waste precious tin unnecessarily. If you find that the bullets shed off too much weight as they expand to give you adequate penetration then you might up the tin to 5%. That should allow for almost 100% weight retention and deeper penetration.
Note: higher tin contents will cause the bullets to soften over time somewhat.

[cajun shooter]

Perimedic, Go to the sticky section of this forum and search for Glen Fryxell. His book is there to read and get some very valuable information from. The member that advised you obtain a copy of the Lyman Cast Bullet Handbook is quite correct. It will serve you well and is one of the on the bench reference books around. Be careful with the amount of tin you add as it is very expensive and each caster has his stash put away.

[sljacob]

also try the lasc web site, a lot of good alloy info there

[cbrick]

I do understand there really is no EXACT formula. So what would be the correct start point for 10lbs batch ratio? Thanks

Your right, there is no exact formula. It all depends on the metal your using and what your trying to do.

For straight lead (IE not an alloy) with no antimony the tin limit is pretty much what you can afford. 10-1 Pb/Sn would be pricey but where such an alloy is needed would work well.

When Sb is in the alloy the accepted norm in the metals industry is to use no more Sn than the percentage of Sb. I assume WW at 2% Sb so I use no more tin than 2% in my WW alloy. When I add WW ingots to my casting pot I weigh the ingots, get out the calculator and add 2% Sn by weight of the ingots.

Rick