Zinc stuck in mold air groves

[Mleon]

Hi I tried a new 9mm mold for the first time. I think my mix had zinc and made a mess. A lot of splatter is stuck in the air groves. Is there a trick to cleaning this mess off the mold? Thanks for you help

[Bird]

I am guessing you have iro molds?..
If so, take a piece of rifle brass and squash the neck to a flat. Hold the brass in hand and use the flat of the neck as a scraper on the mold. Rub in the direction of the air grooves.

[redhawk0]

I've used a torch and brass brush before. It cleans the grooves out nicely. Lead (no zinc formula) generally comes out with just the brush on a cold mold...but zinc is a bit tougher.

You can also try using a sewing needle to scrape it out....again...you have to get the mold really hot first...and use a light touch. You don't want to damage the mold. The torch also gives you control over the heat.

redhawk

[Bird]

I am guessing you have iro molds?..
If so, take a piece of rifle brass and squash the neck to a flat. Hold the brass in hand and use the flat of the neck as a scraper on the mold. Rub in the direction of the air grooves.

[Mleon]

No lee Al mold. A brass wire brush with hot water and soap worked. Thanks

[JonB_in_Glencoe]

I use a soft lead ingot like an pencil eraser, to rub and remove lead alloy splatter from the mold face (when mold and ingot are room temperature). This technique should also work with lead alloy splatter in the vent lines as well.

Also, I doubt your alloy has zinc in it, but this technique should work whether there is zinc contamination in your alloy or not.

[jsizemore]

Most likely your alloy is a little hot and/or your casting a bit fast. Try changing one or the other and see if it cures the problem. If not try the other. I save a sprue or 2 and use it like an eraser while the mold temp is still up and the sprue is cooler. A little brush action finishes it off. Those 9mm molds are tough to get casting right. A bit of heat cycling will help and plenty of practice.

[Mleon]

I don't think my alloy was too hot I was using a thermometer, unless it went bad. Also normally when the mix gets too hot the color darkens, a rainbow kind of forms on top and you can see some boiling. I am experienced in making fishing sinkers and lures. The mix seemed light, messy and it was the first time I used ingots from wheel weights. I gave up with the bullet mold to make the rest of the pot with fishing sinkers. I was having trouble with the sinkers too they would break at the eye part when released. I never had this happened before. If not zinc or a bad thermometer what else could it be?

[JonB_in_Glencoe]

The mix seemed light, messy and it was the first time I used ingots from wheel weights.

Messy as in the dross on top of the melt was like oatmeal and would keep forming more oatmeal like dross as you tried to remove it?
That would be an indicator of Zinc contamination.

I was having trouble with the sinkers too they would break at the eye part when released. I never had this happened before.

If you didn't have the oatmeal dross, this could be due to your never using COWW before. It has a much lower melt temp than pure lead, so if you are casting at a temperature you are use to with pure lead (assuming that's what you normally use?) then the cast item would take longer to freeze and would be more prone to fracturing if the mold is open too soon.

[popper]

you can see some boiling Hugh?

[Walter Laich]

could be you are opening the molds too soon. If the sinkers are breaking you may need to give them a bit longer in the mold before opening it.

[Mleon]

Alot of oatmeal sluge that kept coming back. Also the alloy was sticking to the pot and mold. What is COWW? My quess was zinc or some other bad metal. Just a bad mix last time I try wheel weights.

[JonB_in_Glencoe]

What is COWW?

Clip On Wheel Weights

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