I have been having problems with bullets dropping out of molds easily unless I smoke the mold a lot. Smoking the mold results in slightly undersized bullets which I think is the cause of the key holing when shooting my 458 socom.

I decided that I needed to clean the mold better than what could be done with soap and a toothbrush. I tried to lap the mold using a cast bullet coated with a lapping compound, in this case, a bore cleaning paste. I thought it was a good idea after reading about it on another forum. It didn’t work as well as I hoped.

I ended up putting some paste on the mold then scrubbing it with a dermal tool with a nylon brush attached. It clean the mold like new and the bullets dropped out very easy. Is this method of cleaning too aggressive? Am I asking for a ruined mold? I did this on a steel Lyman mold. I imagine that it would be too aggressive for aluminum and brass molds.

Ranb

You didn't hurt the steel mold any but I think your first problem was a slight burr around the cavity edges. The brushing you gave it smoothed them off.

I suspect the mould is just fine. BFR is probably right; sometimes burrs can give you a fit. As long as the mould didn't open up too much from the lapping and give you a bullet too much oversized, all should be well.

IF you use an oil to rust protect your molds it can be very hard to remove completely. I've found that nothing works better for me than some cheap spray brake cleaner from Walmart's automotive dept.

I have the same problem with all of my molds.
they never want to turn loose of a bullet.

I use brake cleaner to clean the molds.
My molds include a premium mold from one of the renown BPCR mold makers. It sticks too.
I have examined the bullets and the mold under magnification and the molds do not have burrs.
I am really tired of the problem.

I've always used Midway's mold release on RCBS steel and Lee aluminum molds. No rust preventative needed. It seems like graphite suspended in the aerosol propellant.

This is an interesting question as I have found a similar problem but it seems to me to be tempereture related. I use spray oil (balistol) for storage and before use dribble detergent on them and soak in boiling water giving them a scrub with nylon brush. Mould seem to go through a cycle of hard to release bullets then it will let half a doz fall then go back to needing a bit of a wack on the hinge. I give it time to cool and the cycle seems to start again. Think it is temperature related rather than cleanliness but would like to get a solution. Have Lyman and Hoch moulds mostly now and caliber differences don't make a difference, nor dose using straight lino against ww/lino mix or straight ww.

Von Gruff.

quote:

This is an interesting question as I have found a similar problem but it seems to me to be tempereture related.

I gave up casting 22cal bullets for that reason - too difficult to get out the mould! It does seem to be temperature related. I suspect that a hot mould contracts more than the lead and holds tight. One day I am going to 'invent' a three piece mould! It won't that difficult, actually.

Sometimes a mold can be cut a little off center too, only takes a few thousandths. One side will have the circle coming around to enclose the boolit.

I have almost no experience with molding metals. However, I have many years of plastic injection molding and tool making under my belt. There are many problems shared by both processes. A quick trip to SLIDE products website may be very useful. Of all the molding chemicals on the market I liked theirs the best. They have a vast assortment of mold releases, rust preventatives, high temperature lubes, and other use chemicals. Their customer service is outstanding. You might try giving them a call. Their all natural mold release works great for glass bedding. I use their Super grease for all applications on my 4x4 truck. Working in plastics I tried every brand of mold chemical I could find. While not always the cheapest, I was always completely satisfied with the results using Slide products.

Andy B

Much has been said about cleaning molds. I cut my own molds for what I need and I use WD-40 on the cherry and to flush chips. The only thing the stuff is good for in my opinion.
When done, I just scrub with hot water, dish soap and an old toothbrush. My first boolit will be perfect. The size might not be right yet and I have to hand cut more with the cherry but the boolits will be a perfect casting. Boolits usually fall out of the mold when I open it, some need a tap on the hinge and it doesn't matter if the metal is bare or has mold prep on it.
I use a lot of mold prep or Bullplate lube on the sprue plate and top of the mold but the cavities need nothing.