Tin 99.3 / Copper 0.7 Alloy: Is this Ok to use?

[RG1911]

I found an ad for Kester 04-7012-0000 SN 99.3 CU 0.7 solder bars for a reasonable price and wondered if the small amount of copper is cause for concern.

Thank you,
Richard

[Bill*]

It'll be just fine. Treat it as pure tin.

[Jim]

The copper is bonded in at a molecular level. It will add just a tidbit of hardness.

[RG1911]

Thank you! It's $10/pound, shipping included. I *think* that's a reasonable price.

Richard

[cbrick]

That's a great price given todays price of Sn.

Treat it just like pure Sn, the copper percentage for boolits is insignificant. Get either all you can afford or that they have, which ever comes first.

Rick

[sundog]

Copper is good stuff in very small amounts - which is what you will get when added to your alloy. When present in too large a percentage it will cause poor fill out, and when pouring from the pot or a ladle it will noticeably 'sheet' as the copper will try to freeze faster than the rest of the alloy. As above, treat it like pure tin, and 'yer good to go'.

[runfiverun]

tin will mitigate the affects sundog notes above.
that's why they can get away with the percentage they use in the solder.
a 3 to 1 mix seems to work well in boolits up to a certain point [@ 3% copper and 10% tin] then the copper wins.

[S&W-629]

wow that is a real good price.Here in Vt when i buy my solder it's 95% tin 4% antimony 1% copper and thay charge me $27 a # and thay dont give any lub with it ether.

[Defcon-One]

It is in affect "Pure Tin"! You'll never notice a difference.

Good price, too!

[felix]

Ideally, a coppered alloy should have constant stirring during dumping and/or ladeling. Someone having an old motor (erector set?) with a slotted hole spoon or egg beater arrangement attached to a pot should prove or disprove this as an advantage for making much more consistent shooting boolits. Copper is lighter than anything else in the pot, so the draw must be downwards during the stirring.

Frozone, can you design such a motorized dealie to include your PID temperature probe into the melt? The gadget would work fine for any alloy to keep air bubbles to a minimum while pouring. Natural direction of alloy rotation should not be contradicted, depending on where gadget is sent to either north or south of equator. ... felix

[nanuk]

I thought once metals were alloyed, they stayed suspended.

[felix]

Your thinking would be correct, Nanuk, if you exchanged the word "alloy" with "compound". Consider why no two "identical" barrels will shoot the same (except by coincidence). One of these days some oddball researcher will come up with a polymer (a compound) that will be tough and hard enough to be used as a barrel liner (bullets, too). Currently, the liners have to be some sort of metal (alloy). ... felix

[lwknight]

Call it what you like ( alloy or compound) but the copper is dissolved in the tin permanently so no stirring required unless you add something totally dissimilar to break the bond.

Don't believe it? Try to heat and separate a copper pipe joint made with tin solder that is a few years old.
The tin and copper begin to combine as one and the melting point goes very high. The joint will be fused.

[felix]

I will never get an opportunity to use your singular copper-tin mix for projectiles because of the component price is out of my range for such a purpose. ... felix