Tin

[JohnFM]

Does Tin tend to come out of solution or separate from the alloy after repeated melting and use?
When linotype machines were still in use didn't the operators have to regularly add tin to their mix to keep a good fill out for their type?

I'm just wondering because I have a lot of old used linotype and wonder if it would be worthwhile to get hold of some tin to add for a better fill in my molds.

[Outpost75]

If you heat your melt above 750 degs F, you will lose some tin through oxidation each time it is melted. Linotype is tin-rich enough to tolerate several melt-solidify-remelt sequences. If your alloy casts well, dont worry about it. You generally do not want the tin content to exceed antimony content, as the alloy will age soften through cellular precipitation. Optimum strength and hardness exploits the ability of tin and antimony to form a stable intermetallic compound sb-sn, but boundary layer oxidation control for good wetting and mold fillout takes only about 0.5% tin, and perhaps 1% is good as some assurance against loss through melt oxidation, but using a bottom-pour pot with crushed clay or charcoal over the melt surface will prevent this. Given the cost of tin today, using more than 2% just to cook it off and discard in the dross is a waste.

[Defcon-One]

Or just flux with pine sawdust in you bottom pour pot and leave the ash on top as an Oxygen barrier. The metal will be clean and oxidation will be low, if any!

Free sawdust is easy to come by, too!

[GlocksareGood]

You can buy a big bag of clean pine shavings at Walmart for $3.50 and that should last a long time.

Or just flux with pine sawdust in you bottom pour pot and leave the ash on top as an Oxygen barrier. The metal will be clean and oxidation will be low, if any!

Free sawdust is easy to come by, too!

[JohnFM]

Thanks for the replies. All I use is pine chips. I go out to the wood pile and scoop up a coffee can full of saw chips when ever I need any. I only have a dipper, so I leave the ash on top of the melt and shove it aside in a place to I can get a dipper full, about the best I can do to keep that surface from oxidizing.

[mikeym1a]

Thanks for the replies. All I use is pine chips. I go out to the wood pile and scoop up a coffee can full of saw chips when ever I need any. I only have a dipper, so I leave the ash on top of the melt and shove it aside in a place to I can get a dipper full, about the best I can do to keep that surface from oxidizing.

I got a bucket of sawdust at Lowes, for free. I just went where they cut boards for customers with a bucket, and they filled it up. I thought that 5 gal bucket of sawdust would last forever, but, I've used about half, so far. Think I'll get some more this afternoon. Have to help my son fix the water line going into his house, and figure we'll end up at Lowes anyway.