Curing a Cantankerous Mold

[Maven]

14 years ago I purchased a new Ly. #358429 DC mold, but had Hell's own time getting it to drop 2 nicely filled-out bullets per cast. I tried everything: More heat; more tin; bottom pour; ladle pour; using only the rear cavity; using only the front cavity; milling out the sprue plate in order to fill both cavities at once; changing sprue plates; changing the tension on the sprue plate. Nothing worked. Today, I had enough of this nonsense and happened to see a notice a small file (could hardly miss it as it has a bright red tang). Four strokes along each mold block created enough of a bevel to allow the mold to vent properly. Voila, problem solved! It now casts perfectly (with almost annoying regularity). And just think, I was about to heave it, or worse, sell it on E-Bay.

[Buckshot]

[QUOTE=Maven;183458] Today, I had enough of this nonsense and happened to see a notice a small file (could hardly miss it as it has a bright red tang). Four strokes along each mold block created enough of a bevel to allow the mold to vent properly. Voila, problem solved! [QUOTE]

...............That was on the outside edges of the block, right ?

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

[Marlin Junky]

Shimming (or as you guys call it, Beagling) at the top of the mold also works wonders for molds that aren't "breathing" normally. Granted this procedure drops boolits that are slightly out of round at the base but that can be fixed with a sizing die.

MJ

[Maven]

Rick, I gently filed/beveled the inside top surfaces of the blocks, i.e., where the two halves meet, avoiding the cavities entirely. By "gently filed" I mean using little more than the weight of the file itself. It's not as if I hadn't read about this [here] before, but I wasn't sure that the mold's problem was due to venting. Figuring I had nothing to lose by beveling, I had at it and was instantly rewarded with success. Trust me, prior to this it was a major PITA to use.

[buck1]

[QUOTE= happened to see a notice a small file (could hardly miss it as it has a bright red tang). Four strokes along each mold block created enough of a bevel to allow the mold to vent properly. Voila, problem solved! It now casts perfectly QUOTE]

I put a line with a riffler file between the cavities and trace the vent lines with a scribe. sometimes they just cant vent with out a LITTLE CAREFULL file work.....Buck

[Bret4207]

As Buck1 said, "A little CAREFUL work:. I've seen moulds on Ebay I passed on because Ham Handed Harry had a go at "venting" a nice mould with a frickin' horse shoe rasp! I did one mould kind of like Paul did and for ONCE I actually engaged the brain before acting. I gently dragged the top edge of the mould across some 320 paper, just once. I also dragged a carbide scribe along one set of vent line. And I mean GENTLY! Worked like a charm.

I've actually spent far more time on sprue plates. It's almost a "Leementing" type regime I go through, 'specially on Lee's, but also on most Lymans. Flattening and removing burrs and built up lead on a used mould makes a world on difference. I stick with paper on glass or a good flat stone for the sprue plates. Works for me.