mould preparation

[nanuk]

well, it was a quiet shift so I pulled out a couple NEW aluminum 4C moulds that I bought recently

first, I disassembled them, then I noticed something.... they are near IDENTICAL. so I took the plunge and used a carbide engraver and marked the mould number on the off side

then, I scrubbed then well with soapy water and a stiff toothbrush, then same using some comet, rinsed, dried

then, under bright light, and using my 10x loupe, I inspected for burrs. It seems the same edge (leading or trailing?) of the cavities had burrs all along. very minor, but enough I could feel them with a fingertip drag. They were so small, they did not interfere with the mould closure. So I found a hammer handle, and gave them all a medium pressure, brisk rub down.
Second inspection, found only the tiniest hint of a burr... decided to leave it.

before I reassemble and do the heat treatment (one appears to have been cast in, the other appears pristine) is there anything extra I should do?

one thing, I'm gonna drop a piece of shot in the set screws before I install them

any one have other tips?

the weather is warming here, and I have a 1000lbs of lead and 200lbs wheel weights to melt/clean/flux.

thanks
'nuk

[Jon]

I wouldn't use comet on them since bleach attacks aluminum. Don't forget to smoke them, or apply some mold release agent. I put a little bullet lube on the pins and hinges as well.

[runfiverun]

lube them and heat cycle them a couple of times..
try them, you might want to do a little smoothing of the cavitys.

[41 mag fan]

I used to smoke the cavities of all my molds when they were new and the first time or 2 of casting with. I found out I didn't need to do it and stopped completely

[MikeS]

No need for smoking or mould release on a new mould! But don't forget to lube the moulds with BullPlate or equivalent before using them!

[nanuk]

thanks Guys

sounds like I'm ready for the heat cycling

[MT Gianni]

I have heat cycled in an oven and left them on a 350F hot plate for 15 minutes several times. I prefer the oven.

[40Super]

Exactly what is the pupose of heat cycling molds? Other than burning out any water or oil possibly left,I don't see the purpose,the metal shouldn't"move" or settle,and it won't do any type of heat treatment, so whats up with it. So far I've used three new molds without it or smoking and they cast without issues,soooooo,tell me a story:?::?:

[MikeS]

40Super: depending on the metal the mould is made from, heat cycling a mould does a couple of things. First it helps everything settle in (the alignment pins, sprue plate screws, etc.), and it also helps build up a thin layer of oxide which helps the mould release the boolits easier. I too have taken brand new moulds, preheated them, and started casting without heat cycling them, and most good moulds will work fine right away. But I've also noticed that moulds that cast good initially just start casting slightly better after a few casting sessions, which is in effect heat cycling the mould. I've seen very few moulds that didn't cast better after a few casting sessions, but I suppose there are some that won't get any better than they are when originally made.

[MtGun44]

Comet is fine, but you should not leave it on for a long time, it is correct that the
chlorine can react over a long period, not in the 30 sec it takes to give it a good
scrubbing. A good scrubbing will clean off very fine burrs, but not larger ones.

Rinse well with hot water.

Bill

[nanuk]

MtGun44, that is exactly what I did, hot soapy water, then a quick scrub for no more than 1 min Max per side under hot water, then a good rinse, and a scrub with clean brush to remove any signs of comet

Heat cycling tonight in the toaster oven

I rubbed the burrs off with a hardwood handle.

[MtGun44]

You should be good to go. Add a trace of Bull Plate lube or substitute and you are
set.

Good luck, show us some pix. I missed the brand on this molds, or did you say?

Bill

[nanuk]

Bill, they were a couple NOE moulds I bought vendor direct. I am looking at finding some boolits that fit the guns I have, and selling off the rest to fund MORE purchases for some OTHER guns I have that need boolits.

my problem is Work is REALLY interfering with my Recreation time

[MtGun44]

Well, I have this addiction issue.

I am addicted to living indoors, eating 3 times per day and having a car and clothes.
This addiction problem causes a lot of side effects, like having to work for many hours
of the day.

Bill

[rintinglen]

Snort--Bill, that was coffee going out my nose.

[geargnasher]

Nanuk, Bill and MikeS have you covered. I use a product called Bar Keeper's Friend to scub my new aluminum moulds with, it's a powdered cleaner and I don't know what's in it, but it isn't on the blocks long enough to matter. I use that and a toothbrush to gently scrub across the sharp edges of the cavities to remove the sharp edge on a microscopic level. Now you're cringing, I know, but if you use a 10x loupe you can easily see what you're doing and NOT doing, the key is deburring with moderation. Often I will scribe the vent lines into the cavities to open them where they've been plugged with burrs from displaced machined metal, THEN carefully remove the burrs that that process creates, which will certainly make boolits tend to stick in the blocks. The heat cycles do seem to oxidize the surface slightly which makes a better functioning mould. Sometimes I boil moulds in soapy water or run them through the dishwasher, but it really isn't necessary if you do the careful loupe inspection and deburring and a good scrub with a mild abrasive, nylon toothbrush, and hot water.

Don't forget your Bullplate, if you don't have any, you can hurry and get an email order to the Bullshop before they cease operations, or contact Randyrat for some of his sprue plate lube, I believe he ships to your part of the world.

MikeS posted a good thread on how to use the liquid sprue plate lubes and we bugged the staff until they stickied it, it's a good read if you haven't seen it.

Gear

[nanuk]

I do have a 10x loupe, and after the toothbrush scrub, I inspected and still found one edge of all the cavities had tiny burrs, more like a burr edge...

so that is where I rubbed with the hardwood stick.

after that inspection, they look real good.

I'll not do anything else until I get to cast, then I'll know if anything else is needed, but right now, I can't see it.

'nuk

[MtGun44]

Yep, common on Lee molds, a brisk scrub with Comet often cleans them up, but
in some cases I have used a fine X-acto blade to scrape burrs - under magnification,
of course.

Hardwood rub sounds like something I will try next time, thanks for the tip.

Bill

[casterofboolits]

Nanuk, Bill and MikeS have you covered. I use a product called Bar Keeper's Friend to scub my new aluminum moulds with, it's a powdered cleaner and I don't know what's in it, but it isn't on the blocks long enough to matter. I use that and a toothbrush to gently scrub across the sharp edges of the cavities to remove the sharp edge on a microscopic level. Now you're cringing, I know, but if you use a 10x loupe you can easily see what you're doing and NOT doing, the key is deburring with moderation. Often I will scribe the vent lines into the cavities to open them where they've been plugged with burrs from displaced machined metal, THEN carefully remove the burrs that that process creates, which will certainly make boolits tend to stick in the blocks. The heat cycles do seem to oxidize the surface slightly which makes a better functioning mould. Sometimes I boil moulds in soapy water or run them through the dishwasher, but it really isn't necessary if you do the careful loupe inspection and deburring and a good scrub with a mild abrasive, nylon toothbrush, and hot water.

Don't forget your Bullplate, if you don't have any, you can hurry and get an email order to the Bullshop before they cease operations, or contact Randyrat for some of his sprue plate lube, I believe he ships to your part of the world.

MikeS posted a good thread on how to use the liquid sprue plate lubes and we bugged the staff until they stickied it, it's a good read if you haven't seen it.

Gear

+1 on the BKF. I then cleaan with Dawn and a tooth brush to remove any residue.