Derusting old molds

[3leggedturtle]

How do you guys go about cleaning rusty molds? Have 3 that were put away 18 years ago and left alone. They are Lymans with 3-4 lube grooves each. I am at a loss trying to think of a way to get them clean. Have them soaking in WD40 for the last 3 weeks.

[wecsoger]

Obviously you don't want to do a lot of scraping and gouging. (sad grin)

Do a web search on removing rust from a rusty dutch oven or cast iron pan. Several folks have used an electrical method similar to electoplating in reverse. Seems to work well.

[Marvin S]

May also look for some evapo rust.

[J Miller]

When using Evapo-Rust do not leave the molds in for an extended length of time. Evapo-Rust will craze steel if left in too long. Put it in, check it, wipe it off, put it back in .... so forth.

In the past I've taken rusty molds and soaked them in Hoppe's #9 then used brass brushes inside and outside.
Then started casting and let the heat and lead do the rest.



Joe

[Chuck 100 yd]

Have you cast any bullets in them?
I once purchased a Lyman mold that was pretty BROWN
just to get the blocks for a custom mold project I had in mind.
I cast a few bullets in it just for the heck of it and found it cast a
pretty good bullet just the way it was.

If you can get sample bullets from one, drill a hole in the base of one of those bullets and use a wood screw threaded into that hole. Saw the head off the screw and put it in your drill. Butter up that bullet
(lap) with some very fine polishing compound and lap out those cavity's. The rest of the rust can be removed using steel wool and oil.
Have fun and good luck.

[Shasta]

If it is just surface rust, I have had good luck using fine steel wool soaked in WD-40. For the bullet cavities, wrap a bronze or nylon bore brush with the WD-40 soaked steel wool and use a drill to spin it in the cavity. Liberal spraying with the WD-40 washes away the loosened rust.
If the rust has reached the point of being scaley, I've found that even if de-rusted, the mold is pitted and will not throw a clean bullet and is difficult to use.

SHASTA

[Blaine]

Yep, whatever pits are in the mold will show up in the bullet, but, who knows, maybe what you're using them for it won't matter.... Kroil seems to get under rust pretty good.

[Mescalero]

Yep,
It's good stuff, and it will not hurt to soak it in that stuff.

[6pt-sika]

Take Dremel tool with a brass or bronze brush and give it a going over that way .

[Sixgun]

If it is just surface rust, I have had good luck using fine steel wool soaked in WD-40. For the bullet cavities, wrap a bronze or nylon bore brush with the WD-40 soaked steel wool and use a drill to spin it in the cavity. Liberal spraying with the WD-40 washes away the loosened rust.
If the rust has reached the point of being scaley, I've found that even if de-rusted, the mold is pitted and will not throw a clean bullet and is difficult to use.

SHASTA

Word for word, thats also my answer, except I'm no longer a big fan of the "new" WD-40. Kroil or Liquid Wrench dissolves the rust a bit better.---------------Sixgun

[3leggedturtle]

Sixgun, what is the "new WD40"; whats wrong with it?

[Rusty]

I found out how to clean tarnish from silver years ago by dissolving about 2 tablespoons of Arm & Hammer washing soda into each qt. of warm water. Put the water into an aluminum pot and place the silver in the water touching the pot. Let it sit as long as needed to clean off the tarnish. All the washing soda does is improve the conductivity of the water. The aluminum pot sets up a mild reverse electrolysis that causes the tarnish to fall off and cling to the pot. Note this is a mild process so no damage is done. It is also rather passive so there is no chance of doing any damage to the moulds. I'm not sure if it will remove the rust but I know it won't do any damage. I'd say a 6 hour soak should give you an idea as to how well it should work.

[OldWin]

I have quite a few old moulds and have had very good luck letting them soak in Kroil and then using steel wool wrapped around a bore brush and twisting by hand. Repeat this process several times if need be. The secret is don't be in a hurry.

[Sixgun]

Sixgun, what is the "new WD40"; whats wrong with it?

Mr. Turtle, (hey, I like that )

I don't know how old you are but in the seventies and eighties, and nineties? WD-40 would dissolve a quarter pound of rust in 3 seconds flat. (yes, big exaggeration, but the stuff was good)

I have been told that the makers of WD-40 turned to a water base instead of a petroleum base. I'm no chemist but like I said, I have been told that and IIRC, it was right here.

Another product that went to the dogs is 2 + 2 carb cleaner. When we were kids that stuff was very, very nasty. Thats also been cleaned up and for good reason. --------------Sixgun

[Blaine]

FWIW, My recently purchased WD40 sez it has petroleum distillates in it

Lately, I've been using this stuff, liquid, grease, and spray. Way superior for lube/protection.

http://www.fluid-film.com/

I'm still a huge fan of WD40, though....I have been using it on stuff for forty years or more, and have never, ever suffered some of the negative results some have reported.