.454 Roundball Lee Mold Problem

[Colonel_Gentlemen]

The first picture shows the top of the mold after casting about 150 ball, beside the obvious scarring in the aluminum you can also see that the holes have small feathers of metal that seem to obstruct the clean formation of a flat when the sprue plate is knocked away.
The second picture shows the bottom of the sprue plate it has some high points around the edges. The obverse also has some high points.
The third picture shows on of the ball I cast like most it has a seam and a slight lip on the flat.

The pictures probably explain more than I can with my limited knowledge of casting jargon.

I was thinking of lapping the bottom of the sprue plate and top of the mold and chamfering the edges of the outside perimeter of the mold and sprue plate, I am familiar with the concept, having lapped heat sinks for computers before, would this fix the problems I am having with the flat of the ball being malformed and the scarring?
As for the ball having seams, would applying some polish or toothpaste to a ball then spinning it in each chamber half while applying light pressure fix this? It seems it could use some polishing anyway it has mill marks inside ball mold about 1/3 the way up from the bottom of the half rounds.

I was also thinking that taking some super fine sand paper(1k+ grit) and a round nose FMJ and polishing the funnel on the sprue plate in the same way one would polish the crown of a barrel, it seems like this would aid in the sprue cutting then releasing.

Thanks in advance, and sorry if my sentence structure is less than eloquent, I have a harder time with that when I have a worse than usual migraine.

[MikeS]

Hi.

What you need to do is properly lubricate the mould. Don't use Lee's method of using bullet lube, or beeswax to lube it. Get either some mould lube (there's one called Bullplate sold by a forum member), or use a fully synthetic 2 stroke oil, and put a very thin coating of it on the bottom of the sprue plate, as well as the top of the mould blocks, and the alignment ribs/pins.

As for lapping the tops of the blocks, and the bottom of the sprue plate, I can't tell you, as I've never cast a round ball, but with 'normal' boolits having the sprue plate and mould tops mating too smoothly can cause the base of the boolit to not fill out properly (no enough ventilation). Chamfering the edges is probably a good idea.

[Colonel_Gentlemen]

Hi.

What you need to do is properly lubricate the mould. Don't use Lee's method of using bullet lube, or beeswax to lube it. Get either some mould lube (there's one called Bullplate sold by a forum member), or use a fully synthetic 2 stroke oil, and put a very thin coating of it on the bottom of the sprue plate, as well as the top of the mould blocks, and the alignment ribs/pins.

As for lapping the tops of the blocks, and the bottom of the sprue plate, I can't tell you, as I've never cast a round ball, but with 'normal' boolits having the sprue plate and mould tops mating too smoothly can cause the base of the boolit to not fill out properly (no enough ventilation). Chamfering the edges is probably a good idea.

Thanks.

[Rebel Dave]

Colonel
I smooth out all the mating sufaces of the spru plate and blocks. I have never had trouble with it. I also chamfer all the same edges of the spru plate, and block. On lee molds , I also drill and tap an 8-32 allen head screw in to the block, to hold the spru plate screw secure.

I cast mostly .58 cal minnie bullets, and .69 cal round balls. I don't have any trouble with my molds not venting, or gaulling, after doing the above.

Rebel Dave

[Colonel_Gentlemen]

Colonel
I smooth out all the mating sufaces of the spru plate and blocks. I have never had trouble with it. I also chamfer all the same edges of the spru plate, and block. On lee molds , I also drill and tap an 8-32 allen head screw in to the block, to hold the spru plate screw secure.

Rebel Dave

That's a good idea, thanks.

[montana_charlie]

I noted that you 'knock' the sprue plate over.
Turning it by hand is kinder to the mould, and you can keep the plate flat to the blocks as it turns ... eliminating that lip on the sprue flat.

CM

[Colonel_Gentlemen]

I noted that you 'knock' the sprue plate over.
Turning it by hand is kinder to the mould, and you can keep the plate flat to the blocks as it turns ... eliminating that lip on the sprue flat.

CM

I use a rubber mallet, but I'll try doing it by hand, shouldn't be too hard to do now; I lapped and polished the sprue funnels(is that what they're called?).

[OuchHot!]

Forgive me if I point out something that you already know, but all of my lee molds needed a light bevel filed around the perimeter of the sprue plate.....otherwise they gouge the devil out of the mold top.

[Colonel_Gentlemen]

Forgive me if I point out something that you already know, but all of my lee molds needed a light bevel filed around the perimeter of the sprue plate.....otherwise they gouge the devil out of the mold top.

That problem has been corrected.