Finally some decent boolits

[Texantothecore]

I have been fighting a round ball mold that has been throwing bad boolits for months. This weekend I suddenly had boolits dropping out of the mold and they were perfect.

No idea what I had changed, but this is the 5th pour and suddenly they worked. I even shut down and let the mold cool, started back up to test to see whether I had done something unusual in the first go around, but the boolits continued to drop, perfect and no banging on the handles. What a pleasure.

[paul h]

Perhaps there was oil in the mold that you finally burned out of it. It's amazing how oil that you can't even see can outgas and make a mess of bullets for quite some time.

[Texantothecore]

Perhaps there was oil in the mold that you finally burned out of it. It's amazing how oil that you can't even see can outgas and make a mess of bullets for quite some time.

That was probably it although I did clean it with acetone very thoroughly. Next time I will use MEK.

[Texantothecore]

One of the differences this time was I set the mold on top of the furnace top down and the sprue cutter became rather hot. That may have burned some oil and it seemed to make an immediate diffference. Come to think of it, I did have some smoke, probably the last of the oil.

Things were going so well that I started to cut the sprues with my gloved hand. Much faster than using a piece of steel and it helped me keep the heat in the mold rather high.

[williamwaco]

Texan,

I have noticed that some molds do exactly what you are describing.

The old timers I learned from called this seasoning.

I believe it is related to the surface of the mold forming an invisibly thin coating of oxidation. It is usually a pale gold in color but sometimes an iron/steel mold will actually "heat blue" the inside of the cavity.

When I have a new recalcitrant mold and have tried all the tricks with no luck, I will cast as fast as I can ( safely ) until the mold is so hot it takes ten seconds or longer for the sprue to harden.

This means that after eight seconds, if I tilt the mold to the side, the entire sprue puddle is still liquid enough to pour off the top of the mold and splash when it hits the table.

Set that mold aside for the day and work with a mold for bullets you need.

Repeat the above procedure at your next casting session, and you next, and your next.

After three to five casting session, you will ( usually ) start getting perfect bullets.

Note that is for molds that don't cast good, well formed bullets. It will not fix damaged molds or molds with sticky cavities. In fact getting the mold too hot will frequently cause bullet to stick.


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[462]

I've had some moulds that required a few short, break-in casting sessions, too. Made no difference if they were of iron or aluminum.

I think it is one of the myriad reasons why so many new casters become frustrated -- they have a mould that requires that break-in period and they don't have the patience to deal with it.

[runfiverun]

running a new mold for a few short bursts is part of my break in.
i do it to all of them, get em hot run about 50-75 pours in them pretty quickly, set it aside closed up and let it get cold.
if i am doing a long casting session i can get a couple of cycles in, in one day.