light mold polishing with auto-compound

[Andy]

I already own a water-based auto finishing compound for my work and so when it came time to try polishing a mold for the first time I decided to use this as it was fine-grit and on hand. It is a 1500 grit compound that degrades in grit size as you continue using it so not much risk there, and cleans up easily with water and a brush. I just used the method I read about on here where you cast through a steel nut, cool the bullet and mold and reinsert and hand/wrench turn the coated bullet to remove minor imperfections and polish the mold cavity.

Did this on two molds today (and one previously) and all drop bullets more easily than they did before, with no detectable change in bullet diameter. One one mold you could feel burrs before and not after for example (turn it both ways) It is just a very fine polishing (maybe hand turn 40 times or so) so I think this just removes burrs and the like, and smooths the cavities without appreciably affecting diameter (gas checks even click on with the exact same force still).

I'm sure there are many threads on this already just wanted to pass on my personal experience.

[toallmy]

Just so happens I have a nice 4 cavity that doesn't want to let go all the time , and I was considering polishing with toothpaste . If you could post , What is the name of the polish , where can it be found it would be appreciated . Thank you

[bdicki]

http://www.castpics.net/subsite2/Classics/Lee-Menting%20a%20Mold.pdf
Comet.

[MarkP]

I use Comet or Ajax mixed with water to make a thin watery paste. I will drill the base of the bullet (lathe works best) but have used a vise with bullet wrapped in a cloth. Then use a sheet metal screw with Philips head and screw into base.

Apply watery paste to bullet place in mold and rotate gently with a screw driver flushing with water and repeat the paste application. Brush out with toothbrush and hot clear water, place in oven to dry at 225 F or so for 20 minutes.

[toallmy]

Comet I have , I think I will try the pouring through a nut on top of the mold . But a little worried about when I spin the nut it may scratch the top of the mold blocks . I guess only one way to find out .

[Andy]

the paste I am using is menzerna super intensive polish, it is no longer made but whatever their current offering in the 1500 grit range is, is probably functionally identical

[Dragonheart]

You might want tot try using a #2 lead pencil in the cavities. A sharp point will get in the bands. Once coated just brush out the cavities with a nylon bore brush. Your bullets should drop out without sticking.

[toallmy]

I can usually play with a mold and get them dropping boolits , or just lightly rubbing my gloved thumb over them will work . But this one wanted to stick almost every cast , just that one cavity . And as I read this post yesterday I had it on my mind to make this mold fun to cast with . I keep a #2 pencil on my casting bench beside the bull plate lube and yes it usually fixed or helped the sticking , also good for cleaning the blocks , I use the pencil to do all kind of fixes when casting . But yesterday evening I took a couple cast boolits , that had been cast the night before , and with a drill press drilled a small hole in the base set a small 1/4 in drive screw and a little bit a of valve grinding compound gave all 4 cavities a light polish then a dash of comet to smooth them out . a As soon as I cleaned up and warmed up the blocks I got a little flash rust so I oiled the blocks up really good . Then I decided to go down to my dungeon and try it out , I should not have oiled the blocks but that gave me something to do wile the pot heated up . O my goodness it was wonderful I had to make myself stop casting it was just perfect ( the night before I just cast a few before I got tired of sticking bullets ) . I have been casting with saeco 2 cavity wile a 4 cavity set in a box just because it wasn't as much fun due to sticking . I'm sorry I have been so long winded , but would like to thank you gentlemen this post at the right time made me give it a try .

[Andy]

tooallmy, thanks for posting your results, if anything I feel like this compound I tried is on the too-safe side of things, not removing enough at a time to truly fix the problem, but making it a little better each time. I am interested in something a little higher grit now that I see how little it removes. Does anyone know the grit of comet?

[country gent]

I have used Flitz and or simichrome for sticky cavities that I dont want to change size of by very much. Both are metal polishes and very fine abrasives. Red or green rouge could also be used.

[toallmy]

I don't know the grit of comet , but it is very fine it may cut a little bit on aluminum . But if you want to enlarge harder metal mold ( in a reasonable amount of time ) I think you need a little more grit . I have a 1.5 oz permatex valve grinding compound for steal . Just remember that you can't put it back . I used comet as polish .

[gwpercle]

You might want to try Turtle Wax , polishing compound, the whit colored paste, extremely fine and smooth. Comet was too gritty and rough for me. I wanted to polish not abrade.
I cast a bullet , cut the sprue , then used the the sprue hole as a guide to mark center of base, drilled a small hole just deep enough and wide enough , to screw in a Dremel tool screw end arbor, the one that has threads and is made to hold a small felt polishing wheel. screwed an arbor into the bullet base , checked to make sure it was centered and had a boolit lap made.
I never could figure out how to cast anything in place , so I just used the screwed in arbor. You can turn it by hand or slow speed on the Dremel .
Gary