Mold burr

[Possum]

Anyone have a tip for removing a burr from a Lyman mold. The burr is at the top of the bullet on both cavities and both halves. Will a exacto knife work or is the mould too hard?

What works the best?

[grumpy one]

Depends how skilled you are with your hands, and how thick the burr is. I wouldn't try to do it that way unless the burr is so thin you can almost break it off with your fingers, because I know from experience that I usually end up cutting deeper than I wanted to when I use any real force on the knife.

I think there is a sticky on mould maintenance that offers a couple of safer solutions than using a knife, and they seem to work for me. You mount a bullet cast in that mould on a long screw, chuck the screw in a drill, close the mould on it, then use the drill to spin it slowly and briefly. Open it up and look at what has happened. The burr may be gone. If not, the second stage is to coat the same bullet in very fine, mild abrasive - NOT VALVE GRINDING PASTE - such as car polish. Spin it again with the drill, and take another look.

If you are really good at hand-carving, you may be able to cut to the chase and trim the burr with a knife - I just know I wouldn't do that. Incidentally the mould isn't all that hard - comparable to grey iron or mild steel.

[454PB]

I have done some very intricate work using a Dremel tool and steady, slow progress.

[Buckshot]

............Possum, not trying to be a smart ass here (I'm too dense for that :-)), but I just want to make sure I understand?

"The burr is at the top of the bullet.................."

I'm assuming it's a base pour so do you mean it's at the base of the cavity (top of the mould)?


"................. on both cavities, and both halves."

Sounds like it crosses the parting line, yes? If the burr does cross the parting line, or it's at the very edge of the base, then yes you can use an E-xacto knife. I'd suggest some magnification. Be sure to hold the blade at a VERY shallow angle relative to the edge of the cavity. Also hold the knife at a shallow angle relative to the axis of the cavity.

Or if it's on the parting line then the knife should be at a shallow angle perpendicular to the long axis. Use a light touch, and as you pull the blade toward you (don't push it as it's harder to control) also pull the blade upward.

If you have one you can use an ink erasure on the end of a ball point pen. One of those that looks like a pencil? If the burr is on the parting line, lay the block down with the cavity pointing away and the burr furthest away from you. Place the erasure right on the edge with the pen's body lying somewhat down in the cavity and rotate the pen up as you pull it toward you.

Hopefully this makes the burr stand up on the edge. If so you may be able to scrape it off with a thumbnail. If you can't and the burr IS standing up, then run the erasure back along the edge biased to the face of the block, and rotate the erasure so as to casue the burr to lean back into the cavity. Then repeat the first step again. Once or twice of this and the burr should break off.

...............Buckshot

[44man]

Very easy to remove with a piece of Scotchbrite pad. Won't hurt the mould at all.

[Possum]

I got one burr removed and the bullet drops out like a charm. The other side still has a raised place on it and I will work on that one tonight. I found a little dremel sanding disc, broke it in two, and used it like a small file on the first cavity. Must not have sanded enough on the second. Thanks for the input on my first Lyman mold.