Sprue plate bent?

[chris in va]

Could be normal, but...

My 358-125-RF mold hasn't seen more than 1000 through it but the sprue plate looks to be slightly bent. I can see light between the plate and mold, and sometimes the boolit bases get smeared instead of 'clean shaven'. The screw is all the way tightened, not sure what else to do.

[Bulltipper]

what kind of mold is it, what kind of metal? I am having that same problem with a brass .45 mold, the metal under the sprue plate hinge is wearing away and i first noticed it because the sprue plate started swinging too easily. it is now .015 to .020 less than the rest of the block. i couldn't tighten the screw anymore as it was bottomed out so i added a washer. this only made it worse. as i tightened up the screw it pulled the sprue plate even further out over the cavities. i ended up bending the corner of the sprue plate where it hinges just a little bit so it stays flat to the top of the mold. to bend the plate i put the hinge corner in a vise and bent it really carefully with a crescent wrench on the top for leverage. hope that helps, mine is working fine now, but i think i will have to keep bending to keep up with it...

[Bret4207]

If the plate or mould is wearing you need some lube on it. Bullplate (see The Bullshop at bottom of this page) is reputed to be outstanding. When the plate warps a bit they can be flattened by using some abrasive paper on a flat backer and rubbing the plate in a figure 8 pattern till it looks smooth.

[cajun shooter]

Take off the sprue plate and lay it on a piece of glass to see where the problem is. Use lay out dye to show high spots . They are cheap to replace and come in a kit. The advise of Bret is dead on correct about the use of Bullplate. It matters not what the plate is made of it will work.

[MT Gianni]

Well it gets hot and then it gets hit. I stick to opening 2-4 cavity molds with a good welding glove, lube it and have few problems.

[montana_charlie]

The screw is all the way tightened, not sure what else to do.
First, loosen the screw. Keeping it cinched down tight will cause more wear under the pivot hole...and it won't allow the plate to lie flat on the mould.

Just tighten the screw down so that the spring washer is able to apply pressure on the plate, but the plate can be lifted (a bit) with your finger.

If the mould is already worn under the pivot, the fix is to shave the top of the mould.

CM

[Dale53]

I quit striking the sprue plate with a stick some years ago. I "discovered" twisting it off with gloved hands. I wear "welding gloves" (also sold as "fireplace gloves" etc). They seem stiff when you get them (rough out leather with some padding) but they loosen up quickly. I wouldn't be without them.

When you first start casting, before the mould is quite up to heat, you'll need to strike the sprues off. However, as soon as the mould is up to heat, you can then simply twist the sprue off.

I get much better bullet bases by twisting and MUCH less potential for damage to the mould.

I can twist six cavity moulds but admit that they are harder to do than four cavities. In case you think I am built like a gorilla, I am a "Certified Old Fart" and have no more than ordinary hand strength.

Since I started using a hot plate to pre-heat my moulds, it only takes me one or two casts before I start twisting...

FWIW
Dale53

[Maven]

"My 358-125-RF mold hasn't seen more than 1000 through it but the sprue plate looks to be slightly bent. I can see light between the plate and mold, and sometimes the boolit bases get smeared instead of 'clean shaven'. The screw is all the way tightened, not sure what else to do."

chris in va, This is a Lee mold, right? If so it's a small matter to remove the sprue plate,* secure the end with the screw hole in it in a vise and whack it with a claw hammer. Test fit it for flatness until it's perfect, which may mean you'll have to whack it in the opposite direction as well. While it's off the mold, polish the bottom surface and deburr the edges that contact the mold blocks to prevent scoring the latter. Lastly, as others have mentioned, use a welder's glove to open the mold since it saves wear & tear on it and gives virtually perfect bases. Btw, the smeared bases you mentioned occur because you're not allowing the sprue to completely harden before cutting it. Hope this helps!


*removing the screw is the hardest part

[chris in va]

Thanks for the suggestions.

I guess when I say 'smeared', I mean the boolit base has a thin flange of lead now, doesn't matter how long I let it cool. Guess it just needs a little flattening.