Should we leave cast boolits in iron moulds for storage?

[Jim22]

When I first started casting boolits in the 70's it was commonly recommended to leave the last boolit(s) you cast during a session in the mould, sprue and all, to help keep the iron blocks from rusting between uses. Does anyone still do this? Is there evidence, one way or the other, that this works or doesn't?

[45DUDE]

I never clean mine. They stay in a control climate 65-75 degrees year around. I have about 35 molds. 23 are metal. When I buy a rusty mold I bead blast it with sugar sand and then dip it in the 800 degree pot a few seconds to get the color back.Attachment 275749

[Winger Ed.]

Never left a boolit in them, but I used to oil them real well, and put 'em on a shelf.

After a iron mold was totally trashed after I went to use it again---
I now store them in a mason jar submerged about a inch under whatever motor oil I got on sale.
So far, that's kept them in good shape.

They're a mess to clean, but I only have 5-6, and when I cast, I do whatever I'll use for a year or so.

[Bad Ass Wallace]

That's what I do, leave the last cast in the mold, not so much to avoid rust but hornets which build with wet mud. That mud will ruin an iron mold in a matter of weeks!

[Goofy]

Last cast stays in the mould. Been doing this for near 20 years and have not lost a mould to rust yet. I found early on that oil coat is a) a nuisance and b) does not guarantee the rust fairy won't visit.

[porthos]

i have around 35 molds in a 50 cal ammo can. some haven't been used in 30 years. when they were last used ' and at room temp.; i wiped them down with hoppe's (inside and out) maybe it wasn't necessary. and then wrapped each in vpi paper. they are as perfect as they were 30 years ago. i think that the vpi paper and sealed ammo can does the trick.

[sutherpride59]

I keep all of my molds inside and just oil them. Recovered too many bad mold when my father-in law passed that were rubber-banded shut with a bullet in the mold. Just save your investment and oil it and keep it in the house in a box.

[tazman]

I have a can of aerosol Kroil I keep on the cleaning bench(as separate from my loading bench and casting table) that I use to give an iron mold a quick coating when I finish for the day.
No need to clean it when you start casting again. Two or three sets through the mold when hot and it is ready to go. The Kroil can also act as a release agent for a short time with difficult molds.

[GregLaROCHE]

I give mine a quick coat of Ballistol spray, usually when they are still a little warm.

[sutherpride59]

I keep all of my molds inside and just oil them. Recovered too many bad mold when my father-in law passed that were rubber-banded shut with a bullet in the mold. Just save your investment and oil it and keep it in the house in a box.

[Walks]

I can't believe this old wives tale is still going on. My Dad didn't believe in it, and I sure don't. I saw lots of molds for sale at gun shows that had a bullet left in cavities, and rusty. After living at the beach for 5yrs , the only way I could keep rust from my molds was; OIL, LOTS OF OIL !!!
Either Ballistol or recently a switch to Mineral oil.
A couple of good squirts with brake cleaner and good to go.

[Ed_Shot]

+1 for coating iron molds with oil for storage. I now use Mr. Wrench and wrap in a rag. A squirt of break cleaner and they are ready to go again. I've had some of my Lyman molds for 60+ years.

[Boolseye]

I only have a couple iron moulds, so its not a big deal to oil them after use...I also wrap them in anti-oxidizing paper, or whatever that stuff is called. Took quite awhile to de-rust one before, but I learned after that. I also keep an eye on all the steel components of my aluminum and brass moulds.

[David2011]

I never clean mine. They stay in a control climate 65-75 degrees year around. I have about 35 molds. 23 are metal. When I buy a rusty mold I bead blast it with sugar sand and then dip it in the 800 degree pot a few seconds to get the color back.

Just curious, if 23 molds are metal, what are the rest made of?

[Bird]

I oil the molds after casting while they are still warm. The warmth keeps condensation off before oiling. Put them in a small ziplock bag. Next time I want to cast, I clean the molds before starting. I don't leave anything in the mold.

[kevin c]

All my molds are aluminum or brass, but the hardware is steel that I have seen get rusty. So everything gets stored, empty, in ammo cans with a good seal, and with plenty of VCI chips. It's working so far.

[Bazoo]

I oil with mineral oil applied with an artists brush. I did use remoil but I checked one after a few months and rust had appeared. The best way I've found to clean them is with lighter fluid. Spritz it before use to remove excess, make sure it's dry, get it hot and fill the cavities with fluid and it boils. Cleans real well.

[oldhenry]

Since I started casting in the 60's I've always left the last castings in the mold with sprue intact (that was the thing to do then). I still do this with the iron molds. I have never experienced any rust problem in the cavities.

[Hossfly]

I think when they say metal their referring to iron or steel, anything that would stick to a magnet. And rust. What I do is coat anything that might rust with LPS #3. It has a waxy feel that last a while. It just looks nasty and needs extensive cleaning before using, but you will have no rust.

[Der Gebirgsjager]

I read the "leave the last bullet in the mold" information many years ago. Being new to casting at the time, and not knowing if the information was good or bad, I decided to do it. However, after casting several hundred bullets in a session I was just programmed to open the mold and drop the bullet, so I ended up leaving the bullet in only about half of them, as I figured once the handles had been opened and the bullet dropped, replacing the dropped bullet in the cavity would result in an air gap between the sides of the bullet and the walls of the mold. In the instances where I did remember to not open the mold and leave the last bullet in the mold I noted no ill effects after a couple of years storage. I oiled the exterior of the molds. In the cases where I had forgotten to keep the bullet in the mold I oiled the entire mold and encountered no rust. Present practice, for many years now, has been to oil the molds and wrap them in no-rust paper secured tightly with rubber bands. That has worked for me. I'm a great fan of no-rust paper (Brownell's) and use it with each gun I store that is not in use. I usually have scraps left over to use on small items like mold blocks.

DG