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View Full Version : Mould Clean-Up Suggestions & the Winner Is...



John Holland
01-05-2011, 06:27 PM
First of all I want to offer a most sincere thank you to everyone who took the time to offer their advice.

Ok, here we go….I really didn’t know where to go to use someone’s ultra-sonic cleaner, so I dismissed that approach.

I did take Joe Plakis’ advice on oven cleaner and stayed away from it.

There were suggestions for rubbing alcohol, acetone, and white vinegar w/lemon juice….tried them all with a stiff bristle brush….and....I swear I could hear that mould sit there and scoff at my efforts!

Richard’s suggestion of a soda-blaster is way too advanced for Buffalo’s rust belt economy.

There was a suggestion to send it back to Rapine….well….he’s just plain out of business.

Another helpful soul suggested throwing it out. Well, I wasn’t raised in today’s throw-away society, so that didn’t appeal to me. Besides, now it had become personal….It was ME against THE MOULD!

You’ll remember early on in this topic Wayne Shaw suggested carb & choke cleaner, which led to a brief discussion proving Wayne IS older than the most of us.

I really hate having to go out and buy something, so I hunted around and found a can of brake cleaner, and I liked Greg Ogden’s theory….fix it, no matter how long it takes.

Now for Paul Harvey’s “The Rest of The Story”. The liberal amounts of brake cleaner not only dried out the surfaces of the mould thereby turning some of “the stuff” into a hard packed dust-like consistency, it also sucked every bit natural oil out of my hands. I mean, they looked like they had been freeze dried in the Arctic! Using a bamboo scraper and more brake cleaner I removed a very little bit from the surfaces.

I’m not really known for excessive amounts of patience…I think it’s the Irish & Scottish heritage…wee people with wee amounts of patience. So, now it was time to take things into my own hands. First, to disassemble the mould. The thing nearly ran away in terror when it saw the hammer and drift pins come out. Yep, that’s right you nasty little thing, I’m going to perform surgery on your caked & baked carcass. I removed the two bottom roll pins first so as to release the base pin and plate. There was so much gunk there that the plate couldn’t even move freely. Next were the two roll pins for the mould blocks. They were really tight, and nearly sealed in with whatever the mould had been treated with. The same goes for the mould handle channels, I had to pry the blocks off the handles. The only thing that came off easily was the sprue plate. The tops of the blocks and the underside of the sprue plate had been so heavily coated there were heavy drag marks on both pieces. It appeared as if they were badly scored. As it turned out, they weren’t and the underside of the sprue plate came out bright.

Now that everything was in pieces, with no apparent casualties, I went to work on the outer surfaces of the blocks because there was nothing to hurt by experimenting on them. By using the brake cleaner and a Scotch-Brite pad the stuff came off fairly well. This worked well on the flat surfaces, but I couldn’t get into the lettering and numbers on the sides, which weren't even visible until I started cleaning.

I then switched to a copper/bronze bore brush to scrub with and the lettering began to clean up with no obvious damage. Next were the mould cavities. By using the brake cleaner and Scotch-Brite very gently with the bamboo scraper I was able to remove the heavy encrustations in the cavities. I knew I had to be very careful because I didn’t want to damage the sharp edges of the grease grooves, so I went back to the bore brush. Once I got through all the baked on black stuff and down to the smooth surfaces of cavities I found them to still be coated with yet another agent of some sort. It was a pale yellow coating! It was definitely a coating because I could see bright surfaces in areas that weren’t perfectly coated. I stopped at this point.

The reassembly process was most interesting. It caused me to suspect this particular mould has been a problem all its life. When I first tried casting with it I could see the blocks didn’t meet tightly, and the cast bullets showed this with a seam around them. I wrote it off to the surfaces being so unevenly coated. Not so, for once the mould was held together with clean surfaces I discovered it rocked on the locating pins! I determined the locating pins were too far out and the mating holes on the opposite block were a smaller diameter than the the body of the locating pins. This means that only the radiused ends of the pins are to enter the mating locating holes, not the full body of the pin. Rather than try to ream the holes to match the pins I seated the pins deeper into their own holes by 0.020” each. Low and behold the blocks now close perfectly! The rest of the reassembly operation went smoothly. As soon as I unearth the casting bench I’ll let you know how it works!

Thanks again to all!

John Holland