Iron Molds and Burrs

[justindad]

Last summer Midway had several sales on Lyman, RCBS, and Saeco molds. A few that I picked up had some obvious burrs around the cavities. I casted before I did anything just to see what would happen, and the boolits rolled out with ease. Now the smalled burrs on aluminum and brass molds I purchased from NOE made boolits stick so aggressively that the mold would cool off before I finished rapping at the handle hinge. I could not stop myself from stoning the burrs off the iron molds, and all is well.
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Anyways, seems that iron molds drop boolits more easily than brass or aluminum when a burr is present.

[Winger Ed.]

I've run into them too.
I have to caution myself about getting to aggressive with them so I rub the mold on a piece of blue jeans.
It takes longer than other things, but you shouldn't have to worry about rounding any edges either.

[jdgabbard]

Breaking the edge with a 1000 grit gunsmithing stone will help with the burrs. You have to be VERY careful though to not remove too much material. I've never heard of the blue jeans trick, but I'm sure it works. A few light touches with a cloth wheel with a little green or white polishing compound might work as well. You just have to be very careful not to remove too much from the mold or you'll ruin it.

[Winger Ed.]

Old (cotton) blue jeans are pretty handy for various polishing sort of uses, especially if you're not in a hurry.

[405grain]

Whenever I get a new set of molds one of the first things I do is remove any burrs with an ink eraser. (not a pencil eraser) ink erasers aren't very common anymore, and the only place I was able to find them was Amazon. They're just like a pencil eraser except that they are white instead of pink, and they have super fine powdered sand mixed in with them. They easily remove any microscopic burrs from the cavities and sprue plate holes without the danger of causing any damage to the molds. Also, on a cold set of molds an ink erasure can be used to remove any lead from the bottom of a sprue plate.

FYI: another thing that I always do with a new set of molds is to very lightly chamfer the edges of the holes that the alignment pins on the mold blocks seat into. With new molds, sometimes I can see a tiny bit of light coming through when the blocks are closed. The gap might only be .002" or so, but that means that the cast bullets will be that much out of round. Usually after I (very lightly) chamfer the edges of the alignment holes the mold blocks will close up so closely that no light gets through.

[hc18flyer]

'405grain'- Your information is exactly why I spend way too much time on this Forum, learn something nearly every day! hc18flyer

[justindad]

I’m going to buy an ink eraser. I’ve used a strap of leather, biodegradable silverware, and a wood pencil to remove burrs. Imagine you’re using the burrs as a cheese grade on the pencil. I can appreciate how a person could ruin a mold with a stone, but mine turned out nicely - very light touch, as if you’re trying not to do what you’re trying to do.

[405grain]

Here's where I got mine: https://www.amazon.com/Sand-Eraser-I...59&sr=8-5&th=1

[justindad]

It’s in the mail. Thank you!