Steel Mold Maintenance Question

First time using a steel mold tonight. RCBS 2 Cav. Its pretty amazing dropped some awesome bullets and they are spot on round with no variance at all. Pretty impressed. How should I store it between sessions. More specific, what should be done to the mold after casting to prevent rust? I have read a couple things of people spraying them down with the WD-40. Would add a whole new process every time you want to cast from aluminum, you have to clean it up as it's a brand new mold ? I wiped it down while it was still hot with 2 cycle oil, left cavities full... which Ive never done with the aluminum molds but figured I would try it with the steel. Any quick tips would be greatly appreciated. Hopefully I'm not posting this in the wrong section.

VPI powder. I bought a little can about 40 years ago and just put a dab inside the cavities after a session.

I preserve all of my iron blocks with Kano Kroil from Brownells. No rust. Preheat blocks on a Proctor-Silex hot plate from Wal-Mart calibrating with a 350 degree F Tempilstik crayon. The oil sublimes away and you can cast good bullets immediately. Learned this by trial and error as commercial caster and loader years ago. Works.

I use brake cleaner or electrical contact cleaner to degrease mine. RCBS makes a good casting mold!

My shop is insulated and drywalled and we don't have high humidity so molds go in the tool chest with cavities empty.

Motor oil cut with diesel fuel, specific ratios are "whatever", but light on the oil, spray on the mold halves, put the mold away, in the garage, in high humidity Florida. No corrosion noted.

Pre-heat with hot plate (Mr. Coffee - base only). Set mold bottom in liquid alloy (burns off diesel) - maybe 2-3 minutes. Turn over. Set spru plate in liquid alloy. Cast.

Works for me...

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Originally Posted by HWooldridge

VPI powder. I bought a little can about 40 years ago and just put a dab inside the cavities after a session.

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I did a search on that, have never heard of it. So does it come off easily on your next casting session, how do you remove it?
The other question, I didn't see it for sale anywhere really. An aircraft supply came up but was no longer available on their site. Another site I seen was selling the desiccant packets with mention of it. Is it the same powder in the packets?

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Originally Posted by Outpost75

I preserve all of my iron blocks with Kano Kroil from Brownells. No rust. Preheat blocks on a Proctor-Silex hot plate from Wal-Mart calibrating with a 350 degree F Tempilstik crayon. The oil sublimes away and you can cast good bullets immediately. Learned this by trial and error as commercial caster and loader years ago. Works.

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Never heard of this either, but Home Depot came up as a supplier, looked like it was easy enough to pick up. I have an electric hot plate that I sometimes use to keep the mold hot, at what temp should this be? I seen mention of using a coffee machine hot plate, maybe I'm getting it too hot. But I will look into this Kano Kroil, thanks for the tip.. Assuming the melting point of the oil is 350 deg?

I use the WD40 method.
When the mould cools, I spray it with WD40 and wrap a plastic bag around the mould (not the handles) and tape it shut with masking tape.
They go into the cabinet under the bench.
My casting/reloading area is a converted unheated horse stall in the barn and thus is subject to heat/cold/humidity.
Never a speck of rust.
Cleanup time? Brake cleaner, a rag and QTips do a great job.

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Originally Posted by Manns50

I did a search on that, have never heard of it. So does it come off easily on your next casting session, how do you remove it?
The other question, I didn't see it for sale anywhere really. An aircraft supply came up but was no longer available on their site. Another site I seen was selling the desiccant packets with mention of it. Is it the same powder in the packets?

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Yes, VPI = Vapor Phase Inhibitor. Brownell's used to sell it, which is where I got my can. It may be bad by now just based on its age but doesn't seem to cause any rust issues. Of course, I also keep my molds in a controlled atmosphere so the VPI may be redundant.

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Originally Posted by Outpost75

I preserve all of my iron blocks with Kano Kroil from Brownells. No rust. Preheat blocks on a Proctor-Silex hot plate from Wal-Mart calibrating with a 350 degree F Tempilstik crayon. The oil sublimes away and you can cast good bullets immediately. Learned this by trial and error as commercial caster and loader years ago. Works.

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Originally Posted by Manns50

Never heard of this either, but Home Depot came up as a supplier, looked like it was easy enough to pick up. I have an electric hot plate that I sometimes use to keep the mold hot, at what temp should this be? I seen mention of using a coffee machine hot plate, maybe I'm getting it too hot. But I will look into this Kano Kroil, thanks for the tip.. Assuming the melting point of the oil is 350 deg?

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While it depends on the storage conditions (humidity). I'm in MN, so summers are humid, winter is dry.
Anyway, I also use Kroil, I use the aerosol version. Just spray it on, then store in a airtight plastic food storage container...truly they are only "relatively airtight." As I have found some surface rust on untreated iron molds. I'll also add, that not all iron molds are made from the same alloy. I have found RCBS meehanite iron is less likely to rust than some others. The worst one was a Balista-cast mold.

Oh, I should add, that I do wash my Kroil treated molds before casting (Dishsoap and Hot water and toothbrush), instead of preheating as Outpost mentions...but I am sure preheating them will work too, if Outpost does it.

I just went through this drill. VPI (or VCI) powder and paper can be purchased online. Zerust is a major manufacturer of such products. The only sources of VCI powder that I found were in large quantities - for industrial use. I ended up buying plastic bags and 1X3" VCI strips that I cut into 1" squares. Brownells sells the plastic tabs and VCI paper, but prices are probably higher.

You didn't say how long you want your storage to last? For short term storage all of the above methods that provide an air barrier to the metal will work.

I sometime cast thousands of bullets from a mold then the mold may go into storage for an indefinite period of time. Here in the Gulf Coast humidity is a problem and many of my old molds like H&G are not easily replaced, if at all, so storage is not a maybe it works, for me. First I clean my molds, removing any build up. Then they get a dip in heavy 90+ weight gear oil and go into an small open heavyweight clear plastic bag. Then the mold/bag is placed into a vacuum bag & sealed. The inner bag protects the seal from puncture from block corners, if in doubt add more layers.

Once sealed the bag/seal can withstand a flood or opened 30 years later and look like the day it was stored. Yes, I have had some items stored that long. The vacuum seal, obviously no oil, works well on cartridges, brass, etc, etc. I have even heard some use a vacuum to seal food.
Attachment 300569

After the mould is cool to touch I apply mineral oil with a small paintbrush to the cavities. I don’t apply it everywhere. Then when ready to cast again I remove what I can with a rag, then the rest with lighter fluid. I use the lighter fluid on a hot mould. When it’s about half up to temp, I open the sprue cutter and fill the cavity with ronsonol lighter fluid. It will boil in the cavities and remove all residual oil. It has never burst into flames in the 5 years I’ve been doing this. I lube the mould every couple times I cast, before heating, I remove the sprue cutter and use a carpenters pencil on the block tops, sprue cutters bottom, alignment pins, sprue pivot pin and hole. I use a carpenters pencil to reapply graphite after a lead smear under the cutter too, and it works great!

+1 on the kroil. After casting while mold ( steel,brass or alum) is hot I put it on and inside the mold coating it all over. When it cools, goes in a ziplol bag.
I heat up the mold on the pot and if necessary give it a spray of brake cleaner in the cavity’s if needed to remove excess oil, then reheat and cast away.
Kroil works great on a warm barrel and keeps copper and lead from sticking. Seems to make cleaning easier the next time shooting.

Mike

Awesome tips from everyone greatly appreciated. I will be casting fairly often maybe a month or two pause after I get a pile built up but I don't want to not prep it right and the pause ends up being longer than expected etc have rust on the mold. I'll put it in a ziplock back a try some of these methods.
Nicholst55, you mentioned the strips, so assuming its not powder form, its just absorbing moisture when stored with the mold? as in a desiccant pack

seems we had this topc a week ago or so. I NEVER put oil of any kind on molds. I use steel 50 cal ammo cans. Put your molds in hot and close it up after a minute or two. They will vacuum seal and that's it-DONE.
I do put dry desiccant in bags n the cans just for added protection. I have used this method for almost 50 years and have never had rust issues. Why make more work out of it. Ammo cans can be had at harborfrieght for about $16. Many other sources.

Hornady 1-Shot Cleaner_Lube.
No rust - Ever
Dries dry.
No pre-cleaning before casting.
2nd Cast w/ pre-heated mould is perfect

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Originally Posted by mehavey

Hornady 1-Shot Cleaner_Lube.
No rust - Ever
Dries dry.
No pre-cleaning before casting.
2nd Cast w/ pre-heated mould is perfect

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I have some of that on hand, have not picked up the Kroil yet. Interesting.

Make sure it's the Cleaner lube, not Case lube.
:coffeecom

I prefer aluminum and brass, but my steel moulds get a liberal amount of motor oil. A little Simple Green and a toothbrush gets it ready to cast.

Maybe it's overkill but there's no chance of it rusting.

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Originally Posted by JonB_in_Glencoe

While it depends on the storage conditions (humidity). I'm in MN, so summers are humid, winter is dry.
Anyway, I also use Kroil, I use the aerosol version. Just spray it on, then store in a airtight plastic food storage container...truly they are only "relatively airtight." As I have found some surface rust on untreated iron molds. I'll also add, that not all iron molds are made from the same alloy. I have found RCBS meehanite iron is less likely to rust than some others. The worst one was a Balista-cast mold.

Oh, I should add, that I do wash my Kroil treated molds before casting (Dishsoap and Hot water and toothbrush), instead of preheating as Outpost mentions...but I am sure preheating them will work too, if Outpost does it.

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When I was in the business of packaging and shipping hazardous waste (and also while packaging evidence in the crime lab) I found that any container that is "closed up tight" will tend to condense moisture inside due to ambient temperature changes. I once opened an empty steel drum that was one quarter full of water, from just sitting around. Anything that has an actual seal such as a GI ammo box should always have a desiccant inside, and it should be changed regularly if rust is to be avoided.

Wayne

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Originally Posted by mehavey

Make sure it's the Cleaner lube, not Case lube.
:coffeecom

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Ya I think I have the case lube, good catch. Wonder what the diff is...

FWIW: I've gone through a lot of gun cleaner/lubes/preservers and other "CLP' products,
but I discovered 1-Shot Cleaner Lube for gas shotgun cleaning and had my eyes opened
big time. Not only fast wash-off carbon benefits - but a subsequent dry rust preventer
that I could not believe so effective -- until I left bare metal outside for 18 months w/ half
of it sprayed lightly with 1-Shot.

https://www.chuckhawks.com/hornady_one_shot2.html