Best way to clean a brass mold?

[tayous1]

I have an old brass mold that is in need of cleaning and wanted to find the best way to do this and not damage the mold. Any advice please!

[dg31872]

This is a timely question for me.
I have a brass MP mould that i bought second hand, and apparently has lead tinned to it.
Some places the lead is thicker than other places. The cavities are clean, but some vent groves and other places are filled with lead.
How hot can I get this brass without damaging the mould?

[tayous1]

This is a timely question for me.
I have a brass MP mould that i bought second hand, and apparently has lead tinned to it.
Some places the lead is thicker than other places. The cavities are clean, but some vent groves and other places are filled with lead.
How hot can I get this brass without damaging the mould?

I get you on that! Mine just been used a lot and is ugly especially since I received a new MP mold on the mail the other day!
My old one has the problem of now leaving tags on the boolits and very dark black residue on the outside of the mold.

I was looking at a few things to clean it but wanted to ask here first don't want to take brassall or throw it in my wet or dry tumbler without knowing the effect!

[45DUDE]

Don't scrape it. I have a bead blaster I use with sugar sand that doesn't remove metal. I wonder If you could dip it in a pot of lead long enough to dislodge the lead? You could polish the outside with a fine wire wheel from a hobby shop if needed. I bet you could get the lead off with a propane torch.

[Green Frog]

I’ve had good luck removing minor discoloration by gently rubbing with grey Scotchbrite. I wouldn’t do any aggressive cleaning on brass unless it was absolutely necessary.

Froggie

[ShooterAZ]

I have heated the mold just hot enough to be able gently remove the lead. A bamboo skewer does a good job (I sharpen a flat edge on them). I've also used a sharp edge of a cast boolit to scrape lead off too. Always heat it up first, and don't put too much pressure.

[rintinglen]

^
This is what I have done. Hit it with a propane torch then scrap the molten lead off with a skewer. I keep all metal away from my brass and aluminum molds.

[StrawHat]

Don't scrape it. I have a bead blaster I use with sugar sand that doesn't remove metal. I wonder If you could dip it in a pot of lead long enough to dislodge the lead? You could polish the outside with a fine wire wheel from a hobby shop if needed. I bet you could get the lead off with a propane torch.


Bead blasting and wire wheels will tear up a mold. Probably not a good idea.

Kevin

[Bent Ramrod]

I’ve gotten whiskers out of vent grooves by getting the mould up to casting temperature, putting a tiny amount of Bullplate Lube on the mould faces with a Q-tip, casting a few more to allow the liquid to wick under the lead, and then wiping the faces with a burlap cloth, or a paper towel held with gloves.

Don’t scrub the yellow patina off your blocks or cavities. That is the oxidation layer that you need in order to cast well-filled-out boolits, and keep more lead from sticking to the outside. Shiny brass moulds, new from the maker, need to be broken in from heating and use.

[45DUDE]

Bead blasting and wire wheels will tear up a mold. Probably not a good idea.

Kevin

Hobby shops <some> have a very fine wire wheel and sugar sand is very fine.<like powder> I have glass beads also. I have used this method on antique carburetors for 35 years. You have to use a low pressure.<35-40> pounds of air and go slow. As with something you only have one shot at =you have to know what you are doing. I didn't say anything about using a brush on the inside. Some times I have to use masking tape.