Zinc okay if powder coated?

From my understanding the issue with zinc when casting is that it's very difficult to get good mold fill-out and you need to run the molds so hot it can cause issues. Molten zinc also chemically attacks both iron and aluminum so mold life is greatly reduced compared to lead alloys.

Interesting post from the Cast Boolits forums:
Zn boolits do not carry the terminal energy of lead since they are about 60% lighter. Their only practical purpose is within about 30 yards. Their light weight also means they will lose energy quickly in a target. This pretty much rules out rifles and leaves close range extreme velocity pistol work. They can be driven to extreme velocities and could be great in defensive pistol use, but if your target moves outside 30-40 yards (depending on boolit weight and velocity) they will be ineffective as compared to lead. Zn boolits need to be sized to exact bore diameter and NO more otherwise excessive pressures will occur. Pistol cases that are not made to withstand 20K PSI should not be used. This will preclude the use of most non magnum brass.

Casting zinc requires very high temperatures as opposed to Lead/Tin alloys. Since it is so much lighter than lead it does not fall into the mold and fill the void unless it is held at a high temperature and the caster maintains a very fast casting ryhthm. They cannot be shot oversize without excess pressure and barrel wear. If there is any misalignment during seating they will ruin cases since they are so hard. Since Zn is so hard multi cavity molds are impractical because the sprues are so hard to cut and this places undue stress on a mold. Zinc and lead are contaminates to each other and if you do both, extreme caution must be made to not mix the two. This will require two pots, two molds, two ladles, etc. If you shoot into a berm you intend to mine for lead later you also need to keep that in mind.

Zn loads produce much less recoil than lead or jacketed loads and will require the sights of a gun to be altered to higher rear sights and lower front sights.

I think that Zn does have some limited practicality in the high velocity close range magnum defensive pistol use.

This is what I know about zinc and it is purely academic and I plan on keeping it that way. There are just to many things yet to discover and tweak with lead. I have been at shooting lead boolits for several years now and have so much yet to learn it is not funny. So I ask myself why bother with something like zinc where its only practical purpose is so small, the wear on equipment and extra equipment just to experiment with things that have already been done are another needless and time consuming frivolity for me at this point.

But I understand your need to experiment!

Zinc is much more expensive to buy than lead. You can scrap zinc and pay for lead. Last I checked the scrapper was buying zinc for almost a buck a pound. He was buying lead for 25 cents. My guess is that you could go to the scrapper and trade your zinc weights at least 1:1 for lead. I think you could make yourself a steel mold and sell sacrificial anodes to some marine centers for much more than that.
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I don't spend too much time separating out the nasty zinc WW. My melting setup doesn't seem to get hot enough to melt the zinc, so i just skim the unmelted weights out when they float on top with the rest of the dross

Auggie D.
 
Auggie Doggie said:
I don't spend too much time separating out the nasty zinc WW. My melting setup doesn't seem to get hot enough to melt the zinc, so i just skim the unmelted weights out when they float on top with the rest of the dross

Auggie D.
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X2

So many in the shooting sports just love to be worried about things..... I learned to effectively ignore zinc on Day One and held to that all through the great "Zinc Wheel Weight Crisis of the 2000's". I only sort things that are obvious and easy to spot as I'm placing the raw wheelweights into the melt, e.g. trash, rubber, stick-on wheelweights (they get done separately), steel and zinc. All else is float and skim.

You have to be grossly negligent to get zinc into your alloy, and even if you were able to do that, small amounts (up to about 2%) do not ruin the batch. Let's face it, you don't really know what's in there, so trace amounts of zinc don't really ruin the integrity of your alloy.

I have about four pounds of Zinc Ingots I made for fun, and it was a bugger to melt. It's very difficult to make into bullets too - you need to really crank up the heat. Pointless, but fun.
 
I know I have melted the odd zinc wheel weight into my mix with no ill effects. Andy says 2% but I think others have noted even 3-4% will not create any ill effects. Since I've gotten a better melter (Canadian Tire propane burner) I can heat up a bigger pot & keep the temperature more constant so the zinc wheel weights always float to the top long before reaching their melting point so they are easy to skim off.
 
ted_dent said:
I know I have melted the odd zinc wheel weight into my mix with no ill effects. Andy says 2% but I think others have noted even 3-4% will not create any ill effects. Since I've gotten a better melter (Canadian Tire propane burner) I can heat up a bigger pot & keep the temperature more constant so the zinc wheel weights always float to the top long before reaching their melting point so they are easy to skim off.
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You will get harder bullets and at 3-4% you may need to ad a smidge more tin to help with fillout
 
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