CAn you get too much soot on a mold?

[jgh4445]

Got my new Lyman 457125 and 457132 molds in today from BACO. I used hot soapy water and a brush to clean them, dried then and then wiped the cavities out really well with alcohol. Let that dry and began to heat up 10 lbs of 30-1 in my Big Dipper pot. Once everything was up to temp I began casting. The 457125's came out great. They have crisp grease grooves, nice flat bases and are consistently weighing 501 to 503 gr. The diameter is a consistent .457. The 457132 is a whole different case. It weighs from 507 to 511 (I weighed 20-25 ) and the diameter is pretty consistent at 454. Wonder what I did wrong? The 457132 should pour at about .457 and weigh 535. Could I have smoked the cavity too much? I think I did both molds exactly the same. Also, the 457132 was missing the two screws that hold it on to the handles. Had to borrow them from another mold. Not a great start casting a bullet that shot so well in my rifle. Also posted this over on the Cast Boolits forum. Maybe someone has had the same issue.

 

[Jurist]

Too much soot!

Here's a good trick,use a magic marker instead,old plumbing trick when soil was not available.

 

[call turner]

Contact BACO, im sure an exchange is in order if mold is undersized.

 

[Skinny 1950]

The sprue cutter could account for the weight differences, try casting at a lower temperature to decrease shrinkage (maybe?).

 

[StrawHat]

A mold should not need anything in the cavities to release the bullet. A bit of polishing should take care of the release problem.

Listen to the boolit guys, they have a bit of experience.

 

[jgh4445]

I did listen to the boolit guys. They said basically not to smoke a mold...ever. Here is response after cleaning the molds and re-melting the boolits:

You guys nailed it! Cleaned the molds really well and started casting. BTW, I've always used a 4 lb bottom dripper to cast with. This is my first experience with a ladle. What I've learned:

Don't smoke it.
Get it clean!
Get it clean some more.
Get it hot!
Don't pour slowly or dribble with a ladle. Set the ladle in the sprue hole with the mold turned sideways, turn it up and let it dump.

The mold that was pouring .457 @ 501 to 503 is now pouring 458-59 @ 505-509.
The mold that was pouring .454 @ 507-511 is now pouring .458 - 460 @ 520 - 525.
What a difference!

 

[StrawHat]

jgh4445,

If the mold ever decides to not drop bullets, a good cleaning is always the first step. Then, if necessary, polishing the cavity(ies). Normally, those are the first two things I do to any mold I get, used or new. It saves headaches later!

Glad things are working for you.

Judging from the bullets, you are loading a 45-70?

 

[jgh4445]

Yep, a 45-70. What do you use to polish your cavities>

 

[call turner]

I NEVER polish my molds . After it cools I store it in a dry place. I DO NOT oil or grease the molds, ever! Usually when casting I heat the mold up on the pot and I through the first ten bullet back in. Once up to temp I get a bullet about every 45 seconds and they run no more or less than .5 gr + - than the desired casting wt.

 

[jgh4445]

I think it depends on where you live. We have a lot of humidity here. After my experience with the soot, I decided to clean up all of my molds. I was surprised to find a layer of surface rust on a couple. luckily I caught them in time. Now, none have soot and all (except the aluminum ones) have a thin coat of Ballistol.

 

[Don McDowell]

A can of spray on clutch and brake cleaner will fix a lot of problem moulds, and make putting one back in service after oiling it and putting it away.