The 'R' word!

[NW Redneck]

Not sure if this should be here or in Equipment so please move if required. I just pulled a mould out of storage and was aghast to find it rusty! It was given to me a couple of years ago and I just put it away as is. I know, BAD TOADY! 20 lashes with a wet noodle! It's an Ideal 245496 single cavity. Mostly rusty on the outside but there are 2 spots inside the cavity as well. One is on the shank and the other is on 1 half of the nose. I'm thinking a brass wire wheel on the outside surfaces but what should I use to clean out the cavity? Will regular gun oil work to protect it after it's cleaned up? Of course I will de-grease it again before use! Should I be oiling it after each use once I start using it regularly, or can I store it with some absorbant media (sillica etc) in a container of some sort?

Any advice greatly apopreciated!
NWR

[44man]

If it is just surface rust with no pitting you are home free. Scotchbrite pads will clean the whole mold. Even 0000 steel wool and a little Hoppes works good. Use a little on a stick to clean inside the cavity. You can also cast a few boolits and use cleanser and water to polish the inside by drilling a hole in the base of the boolit so you can put a headless screw in and chuck it in a drill. Close the blocks on it after putting some cleanser on the boolit and turn slow and easy until clean. Keep cleaning the mating surfaces so the cleanser will not stop the blocks from closing. JB bore paste will also work without removing metal.
I never oil or wax a mold because it takes a lot of work to clean up for the next casting session. I use Rapine mold prep on the entire mold to protect it. It is important to store in a dry location. If you plan on storing it for years, then go ahead and oil it.
On the outside, you can use a wire wheel on a grinder. You won't hurt anything. Or rub on fine sandpaper on a flat surface. As soon as you use the mold it will turn blue again.
Wash the whole mold in hot soapy dishwater, rinse and dry, put on mold prep and you are ready to cast.
Not rocket science, just clean it and use it.

[utk]

NW Redneck,

Try these links for an electrolytic rust removal tip I posted over at Graybeard's:

http://www.bhi.co.uk/hints/rust.htm

http://www3.telus.net/public/aschoep...lyticrust.html

http://www.stovebolt.com/techtips/ru..._derusting.htm

Here is (hopefully) the post:

http://www.graybeardoutdoors.com/php...ic.php?t=58930

utk

[imashooter2]

NW Redneck,

Try these links for an electrolytic rust removal tip I posted over at Graybeard's:

-snip-

I've tried this and it really works. The best part is it only removes rust. You cannot damage the mold any more than it already is.

[MT Gianni]

Iwould go all over the rust with a #2 lead pencil first. Graphite does wonders and is a great mold prep. Gianni.

[NW Redneck]

utk- Thanks for the links on electrolytic rust removal! I'm definitely going to try it! Is this the same process that the electric bore cleaners use? I don't think the rust is deep enough to cause pitting, but if there is minor pitting in the cavity can I polish it out with cleanser or JB as 44man suggested? Or would there be too much metal removed to get rid of the pits? Is there any way to fill any pits? Rubbing a pencil over it to fill it? Would the 'filler' stay in place during casting? I'll clean it up first and hope for the best, but I just want to be prepared for the worst! I just worry about even small defects on such a small boolit! Thaks again!

NWR

[utk]

NWR, I'm no expert whatsoever on this method of removing rust. I just found the links. Read them carefully for all information.

I think electric bore cleaners move the offending metal (lead or copper) from the bore walls to the center electrode.

The rust remover loosens the rust somehow. Maybe by converting iron oxide (rust) into iron which makes the loose rust particles fall off (which will mess up the solution).

Remember, rust is steel that has been eaten away. If the rusting is severe enough to have formed crevices, nothing can be done to replace the steel. You can't "polish out" a hole. Too much "polishing" a crevice will probably just make it bigger (rounded corners on the crevice). Don't know about filling with graphite, though.
This electrolytic process seems to loosen all the rust particles without mechanical action, the good thing about it is that it doesn't remove any fresh material, something that a mechanical method like abrasives will.

I don't think that small crevices need filling anyway, the molten lead won't go into the crevices.
Compare to the method of increasing the diameter of bullets - Beagling - you can have quite some separation between the mold halves before finning occurs (due to surface tension).

For best result, you probably should degrease the mold before electrolyzing. And try the method on a rusty nail first.

A link to using tea for removing rust:

http://bhi.co.uk/hints/rust2.htm

utk

[44man]

If you just carefully remove the rust by whatever method you choose and you find small pits, don't worry about them. They will not hurt a thing except make a tiny bump on the boolit. They will shoot just as good.