Brass Mold Maintenance

[ColColt]

I just received my first brass mold the other day and wondered if there's any specific maintenance you have to pull once a casting session is complete. I've used it once due to the heat we all have been having and since I cast in my garage(attached) I don't like leaving the door open any longer than necessary so, casting was quick with 92 degrees outside!

I wouldn't think there's a great deal to do with the mold but thought I'd ask to be sure.

[geargnasher]

Just use Bullplate on the bottom of the sprue plate and alignment pins once the mould is hot, and maybe wipe them again after to prevent rust. If you use much tin in your alloy you may experience some "tinning" of the cavities, I haven't seen that it causes any problems. If you have an Accurate mould, you might find that it likes to be preheated THOROUGHLY and run at a very fast casting pace to keep the temps up for good fillout.

Gear

[Catshooter]

Col,

Brass can corrode but it takes serious work to get it to do so. I've never done anything to preserve mine. Is the mould all brass? Or does it have some steel parts? If so I'd watch/oil those.


Cat

[longbow]

For short term I wouldn't worry about it. Brass won't corrode easily in normal conditions. I do suggest lightly oiling the sprue plate though and making sure it is lubricated against the mould.

However, I treat pretty much all my moulds the same when they get put away for any length of time. As unpopular as it might be with many, I oil moulds for long term storage and I usually leave boolits in the cavities. My reasoning is that the oil wicks in around the boolits and so completely coats the cavity. Since I have iron moulds that are 40+ years old with no rust I assume it works.

Now with brass and aluminum moulds, the cavities really aren't a big issue but the sprue plate is. You have a steel sprue plate and it will rust given the opportunity. As a minimum, I would wipe the sprue plate lightly with oil or Bullplate and make sure there is some underneath against the mould.

Since I don't mind wiping off oil and have never had casting issues after using oiled moulds I oil all for long term storage.

Different strokes for different folks but that is what I do.

Longbow

[JonB_in_Glencoe]

If you have an Accurate mould, you might find that it likes to be preheated THOROUGHLY and run at a very fast casting pace to keep the temps up for good fillout. Gear

I only have one Accurate mold, and I haven't experienced that,
But mine is a 3 cav. 196 gr. 41 WC. with that large of cavities,
I suppose it gets plenty of heat.
Jon

[geargnasher]

I had Tom design a couple of 3-cavity .45s and they all like to run hotter than aluminum, best results occuring with a light-medium satin frost on the boolits. Alloy temp may have something to do with it, I usually run mine in the 650-675 range.

Gear

[ColColt]

I initially let the mold sit on my hot plate on medium while the alloy melted After the first 3-4 it started casting great. I did put Bull Plate on the sprue plate and top of the mold as well as the pins before I started casting. I discovered as I went as my usual pace, the boolits had a satin sheen to them so, I figured I must be casting at a good pace. No apparent hot spots-just a little "satiny". I was running mostly between 650-675 degrees using ww's plus tin.

Other than the pins and the screw that holds the sprue plate on, it's all brass. I took no measures after casting to do anything to it other than to let it cool down before moving it inside from the garage. Inside and downstairs in my old darkroom covered to reloading primarily, it stays about 72 with humidity below 50% year round.

http://i180.photobucket.com/albums/x220/ColColt/Misc%20Stuff/_DEF4157a.jpg

[Catshooter]

"Humidity below 50% year round."

I'd say that could be a bit important! I live in the Tampa area and we hardly see 50% even inside the house with the AC sucking as much moisture out of the air as it can!

I do as longbow does, oil 'em. Carborator cleaner will strip the oil off nicely just before the mould hits the hot plate prior to casting.


Cat

[ColColt]

I have a two story and the bottom level is partially underground. With the new heat/ac system I had to have put in last summer and it being about 95% efficient, downstairs is several degrees cooler than upstairs. Unfortunately, I feel sure this system won't last 40 years like the other one did. I've never had any problem with anything showing rust downstairs so, that's where my molds, powder and primers are kept. I still put most of them that are iron in plastic sealable containers with those little chips in the containers just to be safe.

[cajun shooter]

I have been using the brass from Accurate moulds for over a year now and find no problems. They stay in the open in my 12X24 shop/storage building. It has an exhaust fan on a thermostat but still reaches over 100 degrees every day of our summer. I use Bullplate on the pins and plate and that is it. I have not seen the problem that gear speaks of. I do however use a hotplate and use two moulds for 20-1 alloy at 750 degrees. I have used the Accurate moulds without preheating and they act the same as any other mould that is cold. They drop bullets that have problems. Once heated to the proper temp that you would do with any mould then they drop perfect bullets.