Cleaning molds

[Michael]

Everyone has their favorite method of cleaning a mold before use. I am one of those that always puts some sort of rust preventive on a iron mold after use, then in a small zip-lock and placed inside of a ammo can. My wife quilts, so this routine drives her nuts, she should talk, trimming, pinning, pressing seams, matching points, blah blah blah blah.

Yesterday I tried something different from my usual cleaning regime of acetone, cotton balls and Q-tips. Granted this was just once, with one mold, surely not a large data population, but it turned out pretty well, will give it another go tomorrow.

Gave the blocks a few squirts of Dawn Power Wash, let them sit for a bit while getting other stuff ready and the pot hot. Went back a while later with a tooth bush and hot water, cleaned right up and once up to temp (took 3 cycles- 2 cav, .45 cal, 525gr, pot at 720), worked like a dream.

 

[Brad]

I have gotten lazy and just get them hot and cast away.
I used to be obsessed over cleaning new moulds but even then some seemed to need to be used a bit before they settled down. My NOE 30-165 RD, a very early NOE mould, was one of those that was a pain for a bit. Multiple cleanings didn't make a difference, wrinkles were the order of the day. After 6-7 heat and cast cycles it suddenly settled down.

 

[KeithB]

We keep a bottle of dawn power wash at the utility sink in the shop. We use it to break up cutting oil on a lot of the things we make. We also use it on our hands instead of more abrasive or harsher cleaners. It works fine!

 

[CWLONGSHOT]

100% Dawn here as well. HOT water and a old tooth brush.

But between uses MINERAL OIL is what I use. But My molds wont sit more than 30-45 days before use. If long term storage Id use different.

But mineral oil most completely flash cooks off on hot plate. One blast with brake clean & in teady to cast NO WRINKLES!

CW

 

[Bazoo]

I coat my iron moulds with mineral oil, then when im ready to cast, I remove as much as I can with a rag. Then, I get the mould hot, open the sprue cutter and fill the cavities with lighter fluid. It does not burst into flames like you'd expect, instead, it boils in the cavity, really scrubbing all the nooks and crannies clean. It works very well for me, though you must be careful not to let a plastic lighter fluid container touch a hot mould other hot objects.

 

[Jeff H]

I've not bought a new iron mould in years, yet I am a Luddite, by the estimation of many.

But I still have several iron moulds and have to care for them. I coat mine with the OLD, ORIGINAL Break-Free, as issued by the US Army in 1982, when finished using them. THAT stuff is about gone and an era about done for good, so something else would be in order. To clean, prior to use,DAWN is second to none. Dawn and really HOT, hot water. It works.

From here, I would try what @Bazoo and @Outpost75 have suggested - mineral oil, found in the LAXATIVE department at WM, and whatever latest version of Dawn to remove it.

I think the common theme here is good, ol' fashioned HOT water.

Funny thing. I have really HARD water. It leaves "water spots" (mineral deposits) on EVERYTHING, to include moulds. You wouldn't believe the frustration said "water spots" would impose upon the humble caster when trying to make pretty bullets. Maybe the new versions of Dawn have something to do with removing water spots?

 

[richhodg66]

I always use brake cleaner and Q tips.

 

[Bret4207]

We use a lot of Dawn here. I've even taken it into the shower with me! One of the few times a name brand seems that much better than the competition.

My moulds- Ive tried everything from coating in wax to vaseline to oils and greases. I think the zip lock bag in side a box of some sort inside a dead fridge witha warming bulb and large desiccant box is about the best. Cleaning is a matter of brake cleaner or carb cleaner for me.

Don't ever store a jug of iodine with a cracked top in said mould fridge! Bad, bad idea!!!

 

[Winelover]

Fifty plus years of using brake cleaner and a toothbrush.

 

[Petrol & Powder]

For my iron molds the anticipated length of storage dictates how they get stored. If the mold will be used again in a few days (less than a month) the mold gets a light coating of Kroil while it is still warm.

If the mold will be stored for a long period of time, it gets grease [RIG] applied while it is still very warm.

The clean-up prior to use is basically the same for both methods but more intensive to remove the grease. Typically, that involves some solvent like acetone or alcohol applied with paper towels and Q-tips.

Admittedly, this creates more work than just storing the mold dry, but rust is an enemy that I take no half-measures with.

To prevent ferrous objects from rusting, you must keep oxygen and water away from the surface. Substances like oil or grease form a barrier on the surface of the iron and are very effective. However, that comes with the price of removing that oil or grease prior to use. It is a price I’m willing to pay to keep rust away.

 

[Winelover]

Pretty much stopped cleaning molds, except for newly purchased ones. Even that's a one time deal. Started storing molds in air tight plastic containers with a small bag of desiccant inside. Containers can be had on Amazon! The ones I use have silicone gaskets in the lids and locking clams on all four sides. Rick turned me on to these. I just write, on the lids, with a grease pencil/China marker the pertinent information.

 

[Rick]

 

[Winelover]

Little lower tech.

 

[Rick H]

Dawn or generic dishwashing soap followed up by acetone.

 

[MW65]

Typically simple green with an freebie toothbrush to cleanup... I use light machine oil in between... will check out the mineral oil... thanks!

 

[RBHarter]

Drop of original Dawn on a wet toothbrush, 3 Axis through the cavities with a hot tap water rinse on new moulds . I used Kroil a few times but I wasn't seeing any difference inside where it was vs outside where it wasn't......in the desert .

I slathered everything in Blockade , Kroil , or wet with Hoppes before the move . Those that haven't been used since the move and steel plates and pins have been basically rust free .

Those that have been used here in the swamp along with new arrivals in iron have just been rolled in VCI paper . All but the H&G have stayed clean . The sheets just aren't big enough to cover and tuck in on both ends so the sprue plate tab and handle hinge are exposed and dust between uses . It's just not a convenient mould to store as an 8 cavity, the 4 cavity Lyman doesn't suffer that with it's clamshell handles it doesn't fit the storage well either but can be tucked in with the sheets .

 

[Bazoo]

I've washed a mould or two, particularly new moulds. But, I can't imagine washing my moulds with dawn before every use. That entails detail stripping the mould, then drying all the nooks and crannies, all the threaded holes. Then reapplying any lube that may be removed. Like the graphite I use on my sprue cutter and mould top.

Detail stripping the mould isn't that bad, but making sure there is not water in the threads, and worries about flash rusting are the main things. Not to mention the time. Sure it only takes 10 minutes... but the method I described with lighter fluid only takes 1 minute, and that is a big time saver of the course of a years worth of casting sessions.

For those that wash your moulds, how do you keep the threaded holes from rusting?

 

[Winelover]

For those that wash your moulds, how do you keep the threaded holes from rusting?

I imagine they wash the mold and immediately start casting with it. At least, that's the way I would do it, if I did it.

Another option, is to wash mold and follow the heat cycling instructions, included with some molds.

Too much work, for me!

 

[Rockydoc]

Funny thing. I have really HARD water. It leaves "water spots" (mineral deposits) on EVERYTHING, to include moulds. You wouldn't believe the frustration said "water spots" would impose upon the humble caster when trying to make pretty bullets. Maybe the new versions of Dawn have something to do with removing water spots?

You can get distilled water in gallon jugs at the grocery store. It only takes a little as the LAST rinse to get the hard water and it's deposits off your mold.

 

[Jeff H]

You can get distilled water in gallon jugs at the grocery store. It only takes a little as the LAST rinse to get the hard water and it's deposits off your mold.

Yes! And thank you!

I keep several gallons on-hand because of the hard water being an issue for things like auto radiators, mixing aniline dyes, etc. Actually had it on hand when I realized what was going on with a particular new aluminum mould, but hadn't considered the "water spots" being any part of a problem until I could see mirror-image anomalies on the bullets one day.


A very good friend hoses his moulds (iron or aluminum) with PB-Blaster after each casting session and then hoses them with brake cleaner prior to each use. The brake cleaner is getting hard to find and expensive and I don't care at all for the smell of PB-Blaster. All that over-spray, waste and vapor - not a big fan of that method.

I only clean a mould when new and leave them alone after that. I store them in lidded plastic bins, which are not particularly air-tight, inside a defunct 50 year old freezer. I also mostly use aluminum moulds these days, so I don't really have to worry about rust anyway.

Each aluminum mould I've bought for several years now gets a hot bath with Dawn and some scouring powder (Bar Keeper's Friend?) with a stiff nylon brush. Rinse in boiling water and usually good to go thereafter. ESPECIALLY if the new mould is a LEE, the scouring powder tends to "deburr" the edges of the cavities, open the vent lines where they terminate at the cavity, but do so without easing any edges.

This may well NOT all be necessary, but it's part of my otherwise non-superstitious good juju, which makes me feel good and confident.