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.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

[gwpercle]

I used to do it because that's what was supposed to be the right way to store them... but I discovered they don't really stop rust in the hot humid Louisiana climate ... it does cover any rust so you can't see it untill it's a bigger problem .
I stopped leaving boolits in the mould and have since found spraying the warm (not hot) mould with a Dry Spray Lube before storing leaves a rust protective coating that doesn't wrinkle boolits or have to be removed before casting ... the dry spray lube acts as a mould release and the boolits just jump out the mould when opened .
Gary

[45-70 Chevroner]

I guess I'm lucky. Living here in Arizona it is dry enough that my molds never get rusted just setting on the shelf, even here where I live now. The elevation is 5660 feet at my house, we get quite a bit of snow sometimes but the humidity is not real high here even during the monsoon season.

[Edward]

sounds like a waste of a bullet /Ed

[MT Gianni]

I have bought several with a bullet in them. I live where things rust if they are left outside under the sprinklers, inside not as much. I just store mine in a wooden drawer.

[FISH4BUGS]

I store my moulds by letting them cool, then spraying thenm with WD40 (blasphemy I know) the wrapping the mould in a plastic bag and taping it shut with masking tape. The handles are typically not taped in the plastic bag.
I also go over all my moulds every year or two just to fondle them and check them out.
I have never found any hint of rust.
They are stored in a cabinet in the unheated remodeled horse stall/man cave. It goes from zero to 90 over the year.

[Dimner]

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.

Kroil doesn't give you the wrinkles when you start casting the next time? I have not found an oil yet that doesn't make my mold wrinkly for the first dozen casts. I'm not coating the cavities, just the outside and sprue plate. So if Kroil doesn't cause this, I'm gonna have to try it.

[BrutalAB]

I store all my moulds in a 40mm ammo can with desiccant packs. Got tired of cleaning the oil off my iron ones and i never oiled my aluminum's sprue plates saw some rust developing on the sprue plates and decided to change things up. Also, never had a problem with rust on anything until i moved across town, only difference in where things are located is before was an attached garage, now its a detached building.

[lightman]

I'm another that tried leaving bullets in the mold and I had one rust. Now I spray them with whatever oil that I use on my guns and store them in an airtight container. A shot of brake cleaner removes the oil when I'm ready to cast.

[photomicftn]

What is the specific lube you're referring to?


I used to do it because that's what was supposed to be the right way to store them... but I discovered they don't really stop rust in the hot humid Louisiana climate ... it does cover any rust so you can't see it untill it's a bigger problem .
I stopped leaving boolits in the mould and have since found spraying the warm (not hot) mould with a Dry Spray Lube before storing leaves a rust protective coating that doesn't wrinkle boolits or have to be removed before casting ... the dry spray lube acts as a mould release and the boolits just jump out the mould when opened .
Gary

[longbow]

I do both! Oil and leave a boolit in each cavity. I don't leave the boolits to stop rust, I leave the boolits to hold oil. If you cut the sprue then open the mould while still warm (not hot) and oil the inside faces then close the oil wicks around the boolits and stays in the cavities by capillary action. oil likes tight clearances. Then I oil the outside surfaces. I have never had a mould rust by doing this.

Some say brass and aluminum moulds don't need to be oiled which is true to an extent but they also have steel sprue plates and if the sprue plate rusts it will damage the softer aluminum or brass mould tops so I oil those too.

Different strokes but this has worked for me for about 50 years.

Longbow