What oil to use on a cast iron mold?

[saz]

I just stumbled on my first high dollar mold after learning with lee 2 cavity molds. I found a saeco .44 keith mold, and after using it I was at a loss for words as to what oil or lubricant to use on it after casting to prevent rust. Is there a specific regimen one should follow with a cast iron mold as far as maintenance? I am just a rookie yet and have only used aluminum molds. Thanks!

[HeavyMetal]

I have always kept my molds, iron , brass and aluminum, in a big metal ammo box, the type with the "O" ring seal around the top, and a latch on both ends of the lid!

I also keep a container of dissacant in with them and renew it every year or so as needed.

Done this way I have never had to "oil" a mold. I also don't leave the last boolit cast in the mold either, I think that attracts mositure, and causes rust.

I've picked up many a mold with a boolit in place that was rusted in the cavity!

However I have never lived in Alaska and you may have to be a bit more careful with storage and cooling periods than I might be.

Cleaning a mold of oil or grease just seems counter productive to me. My reason is a properly boken in Iron mold should have the cavities looking like they have been "blued" by the heat of casting. This actually acts as a release agent and, after break in, should not be removed.

Oiling and then cleaning will certainly do this. Thus everytime you use the mold you'll be breaking it in once more!

Trust me once you get that blued look to the cavities you never want to remove it!

[Le Loup Solitaire]

Avoid it if you can. The program outlined by heavy Metal is really the best way to go. A totally airtight setup with a dessicant will not allow any oxidation/rust to take place....so any cleaning of the mold and its cavities is not necessary. You go from storage arrangement to preheat and when the casting is done and the mold is cool, its back into storage again. LLS

[missionary5155]

Greetings
When I return to Peru I use any motor oil I have on hand. An old toothbrush and a wrap in wax paper. A lite coat will last at least the 3 years I am gone. Molds are in Illinois in a storage room . I do the same with my weapons... in 26 years never a dab of rust.

[Bret4207]

I'm with the guys saying DON'T oil the mould, ever! Put it in a zip lock when warm or use the desiccant idea. I keep all my moulds (and powder) in a dead refrigerator with a large desiccant pack and 15 watt light bulb burning.

[XBT]

I’m with missionary 5155. Any oil will probably be OK, but I use Break Free. To prepare for use I clean the mold with a toothbrush and alcohol and finish off with a spray of carburetor cleaner/degreaser. My molds seem to get dirty after casting a lot and this cleaning makes the boolits drop out better.

I’ve noticed that new molds usually come from the maker oiled.

[cajun shooter]

I use Kroil and the ammo cans. I also have my mold drawers filled with the small desiccant that comes in medicine bottles. Ask your pharmacist to save them as they are a throw away item.

[saz]

Thanks for all the replies guys. After thinking about it the ammo can is probably the way to go- easier too. It is pretty dry up here to start with and I usually dont have any issues with anything in my garage rusting, but I'd hate for that pretty mold to be the first. I am military so getting ammo cans is pretty easy. It is going to get a good cleaning today, heat up the pot and try to figure out this new fangled cast iron mold...... Thanks again everyone!

[Shooter6br]

As Neil Young said"Rust never sleeps"

[Tom W.]

I spray mine with RemOil, and never have had a problem. About the time the mold gets to a good casting temp, the oil is gone and the boolits are good....

[Changeling]

So far I only have 2 but I keep the RCBS in the plastic box it came in sprayed with a little break free.

The Mihec that just came in a paper box I put in a plastic peanut butter jar (Crunchy of course) sprayed with a little Break Free. These make very good mold boxes with a small amount of bubble sheet in it so the mold doesn't bounce around.

[cbrick]

Oil? In a mold?

All I can say is that I'm glad we are talking about your molds and not mine.

Oil in a mold? Never!

Rick

[Tom W.]

Come on Rick, it's kinds like eating calamari... you don't know until you try!

[parrott1969]

Here is an idea for you, place your mold in a mason jar or other container that has an air tight lid and then drop in a hand warmer ( the kind you buy at walmart like $.89 per two pack.) These will act as oxygen absorbers and will bind up the free oxygen and form a vacum in the jar. No oxygen= no rust, problem solved.

[casterofboolits]

Magma Eng. sells a mold presevative spray that doesn't need to be cleaned out when you start your next casting session. I'm going to get a can the next time I order lube.

[mold maker]

Been casting since the late 60s and never oiled a mold. Just put them away warm in an air tight container. Store the container where the temp varies very little.
Never had an issue with rust, except on the outside of the ammo can.

[jonk]

I rarely oil a mold. Only if I think i'm not going to use it for years.

I might have a slight bit of surface rust, but never any in the cavities. I just store them on the shelf.

On those few I DO oil, I use something like Kroil or PB blaster that won't all run down the sides and puddle, but rather flows up and around and keeps the whole thing oiled.

[GeneT]

I Kroil my molds and keep 'em in a drawer. I don't even have to clean the kroil off when I go to casting, and rust is not a problem. If you haven't tried it - do so. It's the easiest way to both prevent rust and get good drops right out of the gate.

GsT

[GabbyM]

Magma Eng. sells a mold presevative spray that doesn't need to be cleaned out when you start your next casting session. I'm going to get a can the next time I order lube.

I have some of that. Wish I knew what wax they use. It's in an alcohol solution.
They charge way to much for it. And you have to provide your own dry alcohol anyway. Available at paint stores.

I've tried spraying rust preventative (Amsoil MR) onto a coffee filter then wrapping the moulds in that. Don't know if it does anything as I don't have a rust issue with the ones I don't wrap. Read someplace drip coffee filters would work to absorb moisture so I stuff them in cans and jugs where I store metal stuff. Spraying them with oil was one of my bright ideas.

[.22-10-45]

Hello, after casting, when mould has cooled to slightly warm, I spray with Mould Saver. available at industrial supply. This contains lanolin. comes right out with brake cleaner...no
casting problems once mould comes up to temp. Sometimes my moulds go for a few years between use..& high humidity MI, I need this protection. I never could figure out theory of leaving last bullet cast in cavity to prevent rust...if bullet truly did seal cavity, you would never be able to get it to drop out! The fact that lead alloys shrink, even ever so slightly, allows moisture to get in there.