RCBS 357 mold won't drop bullets

[sixpointfive]

I am relatively new to bullet casting and cast for a few different calibers. One of the molds I bought recently is a 357/150gr 2 cavity RCBS mold. I used a match many times on this mold but it still will not drop the bullets without heavy rapping. Please help...do I need mould release?:holysheep

[AzShooter]

Clean the mold with soap and water, then with carborator cleaner, then use a butain torch to blacken the cavities. Works better then all those matches. Hopefully that will get you going.

[Edubya]

I've foud that: if #1 I use Kroil on the mould they drop a lot easier. #2 Preheat the mould to 400 degrees before the first boolit. If these two don't work, then you've got a burr in the mould face. You need to check this with something like a cotton swab.
Good luck
EW

[cajun shooter]

No on the mold release. Try the things that were posted for you to look at. I find that mold release brings on more problems than it solves. One being smaller bullets.

[JMtoolman]

If the bullets will not release from the mold it has burrs on the sides of the bullets in the mold blocks. The easy way to tell if this is happening is to look at the seams on freshly cast bullets. Generally there are some scrape marks running parallel with the seam in the mold. Drill several bullets in the center of the base with a drill about 3/16 diameter, about half the depth of the bullet. Cut off the head of a brass wood screw, and use a drill and some lapping compound to polish the cavitys. #360 grit is a good place to start. Do each cavity for 30 seconds or so, until the bullet quits cutting. Cast some more, and if they are still sticking redo the polishing until the bullets will fall from the mold. I used to cut molds for my self, and have done this many times. Best regards, the toolman.

[Ben]

I am relatively new to bullet casting and cast for a few different calibers. One of the molds I bought recently is a 357/150gr 2 cavity RCBS mold. I used a match many times on this mold but it still will not drop the bullets without heavy rapping. Please help...do I need mould release?:holysheep

This works well with Lee molds, but I've also used this process on Lyman, RCBS, and SAECO molds. It has never harmed a mold and has ALWAYS caused the molds to release their bullets much better when the process is completed, the mold cleaned and I'm casting again :

http://castboolits.gunloads.com/showthread.php?t=31700

[gray wolf]

BEN That was exelent

Thank you

Sam

[dragonrider]

Only one way too cure a tough dropping mold. lap it. then clean it well. Do not smoke it and never use mold release. A proberly lapped mold will drop boolits with the lightest of taps on the hinge pin.

[cbrick]

Please help...do I need mould release?:holysheep

NO!

And you shouldn't need to smoke the mold either. If (and I do mean "if") smoking helps at all you are only covering up aother problem such as minor burs.

As was mentioned several times in this thread, make sure there are no burs, the mold is not overheated and your not opening the mold to quickly, are your sprue cut-offs smearing? Assuming no burs the reason the boolits fall out of the mold is because as they cool they shrink and then no longer fit the cavity that made them. If your opening the mold before they shrink enough they can be tough to get out.


do I need mould release?
NO! :holysheep

Rick

[HangFireW8]

I used a match many times on this mold but it still will not drop the bullets without heavy rapping

I have found the most likely places for burrs are:

where the vent lines meet the cavity, and
along the side edge of the cavity that corresponds to where the cherry or bore cutter exited that side of the cavity.

Gently sliding a scribe or dental pick, starting in the cavity and moving over the edge, it should exit smoothly and not catch or stick. Where it sticks, that is a burr. Sometimes the burr takes the form of a wire edge the whole length of that side of the cavity.

Lapping will take it out, especially if you spin the lap in the opposite direction of the burr (cutting into the cavity on that side). If it is a small burr you can just pick it out with the scribe, especially the vent line types.

Typically a burr at the cavity edge blocks a vent line from actually venting the cavity. Once you pick it clear so the cavity can breath, you have now moved the burr so that it holds the boolit in the cavity. Be very careful here as cleaning the vent lines are good, but expanding them at all means you'll get whiskers (especially with very hot melts, pressure casting or high tin melts).

-HF

[sixpointfive]

Ok I will try lapping the mold. I take it that you close the mold on the bullet that you are using for lapping while running the drill.

[Ben]

sixpointfive :

Yes, take about 5 bullets that you've cast in the troublesome mold, coat them with abrasive compound. Place the mold halves around the coated bullet, spin the bullet slowly as you continue to apply gentle pressure on the mold halves bringing the mold to a full closure. It will feel at first like the bullet doesn't want to fit into the cavities of the mold, but after about 5 - 7 revolutions, things will smooth out. Once this occurs, spin the bullet slowly for about 20 seconds.

Remove that bullet. Repeat with bullet number 2, so on, so on.

Clean the mold with brake cleaner , cast with it again to see if it releases the bullets better. If not, repeat the process described above again .

Remember , spin the bullet slow. I use a cordless drill on slow speed for this.

Thanks,
Ben

[sixpointfive]

Thanks all. God bless America!

[NHlever]

One of the things I have done for stubborn molds is to make a square stick, small enough to easily fit in the cavities. Then I wrap it with 0000 steel wool until the mold won't quite close on it. Next, I gently close the mold while turning the stick with my other hand. That tends to take off burrs that you can't see, and smooth things up just enough to make the boolits release easier. Since the steel wool conforms easily to the cavity, it is also a good way to clean up a mold that has just a bit of rust in it.