repairing cavity damage

[hornsurgeon]

i have a lyman 22 mold that got damaged. it looks like one half was dropped. they mate up well, but the cavity got "dented" by the gas check shank. now when i cast a boolit, the gas check shank has a thick fin on it. i can not put a gas check on it without first scraping the thick fin off. can i try peaning the steel ajcent to the damaged area th try to move metal into the damaged area, then refacing the mold? other ideas? or is this mold ruined?

[Johnch]

I know of a master welder that added a touch of weld to the inside of a mould and then worked it down ( TIG, MIG , Wire , Stick I have no clue )
So as to fill the serious rust pits

I know it turned out , but I know he worked on it for a long time between jobs at work

IMO he probely figured if he ruined it , he was only out the time
As the mould was junk before he started

John

[longbow]

A picture of the damage would help.

If the damage is simply a "ding" that raised a little metal on the mould mating faces I would either use a fine file (very fine like a jewelers file) or emery cloth on a piece of flat bar to carefully flatten the raised bit or disassemble the mould and carefully flatten the raised bit by placing fine emery cloth on a flat surface and stroking the mould half on that. I have done both successfully with old abused moulds.

If the damage is at the edge of a cavity then you may have to peen it to correct the cavity seam then file/emery after. I have only done this in a very minor sense to correct extremely small defects. I would be very careful here and if peening it would likely be best to use a small punch with a radius ground on the end and tap it very gently with a light (2 oz.) hammer.

From your description the damage sounds small - the bullets are still usable but have a bit of a fin. If so, then it may be best just to flatten the surface and leave any minor defect at the seam because peening may make things worse.

What is the mould material? If aluminum you will have to be very careful as it is soft.

Longbow

[leftiye]

I would try your idea of peening the metal back into place. Especially do it before you try other approaches as they will remove the metal in question and foreclose that option. Make a cylindrical rod of the size the gas check shank area of the mold is supposed to be. Lay it in on its side against the ding and parallel to the axis of the mold, and tap/hit as necessary to drive the ding out. If I'm visualizing your dent properly, if this doeasn't do it, you're SOL as you can't cut metal back on to the mold block top surface to fill the ding. If you refill the dent on the mold top surface by this method only partially, you may be able to shave the thinner resulting fin down to useable roundness. Seating a gas check may well then swage the boolits to near perfect condition.

[theperfessor]

There is a process called "metallizing" where a metal plasma is sprayed onto a metal substrate to build up worn areas. (I will add that I have seen but not performed this process.) It is used to build up worn shafting and such prior to remachining. The heat is diffused, not concentrated as in other welding processes, and warpage is greatly reduced.

I think there is a "mask" material that can be used to limit where the plasma spray sticks. Perhaps a local weld shop or tech school might be able to help out. If you can get the material built back up, then it probably wouldn't be too hard to use files and emery cloth to carefully remove the excess and restore the utility of your mold.

I've got a six cavity SAECO .45 SWC mold that has two bad cavities where the material has broken away between them at the base, leaving a fin as you described. I've been tempted to try this and just haven't gotten around to it yet. If I do, I'll post the results.

[pjh421]

If it was mine, I would use this as an excuse to get a new mould or two.

Paul

[Larry Gibson]

I've repaired a couple moulds over the years with identical damage. Take a punch that is just smaller than the GC shank diameter. Round the tip at an angle as pictured (apologise for my scribblings) and as close to the radius of the GC shank as you can. The angle is dependant on how far into the mould the damage is. I polished the tip smooth after grinding to shape. Clamp the mould into a vise (smooth jaws or padded with some copper/bronze/aluminum) so the mould halves are clamped together. Insert the punch into the cavity sideways and gently tap the peened metal back into place. It will peen back into place against the other half of the mould. Not hard to do but the important part is the correct shape of the punch tip so you are not peening the edge over. You may also have to take a strip of very fine sand paper under a flat file and smooth the top face of the mould so the sprue plate lays flat.

Larry Gibson

[dubber123]

I've repaired a couple moulds over the years with identical damage. Take a punch that is just smaller than the GC shank diameter. Round the tip at an angle as pictured (apologise for my scribblings) and as close to the radius of the GC shank as you can. The angle is dependant on how far into the mould the damage is. I polished the tip smooth after grinding to shape. Clamp the mould into a vise (smooth jaws or padded with some copper/bronze/aluminum) so the mould halves are clamped together. Insert the punch into the cavity sideways and gently tap the peened metal back into place. It will peen back into place against the other half of the mould. Not hard to do but the important part is the correct shape of the punch tip so you are not peening the edge over. You may also have to take a strip of very fine sand paper under a flat file and smooth the top face of the mould so the sprue plate lays flat.

Larry Gibson

I disagree Larry, Monet would be jealous of your artistic renderings. Well OK, maybe Picasso...[smilie=1:

[Larry Gibson]

They say; "a picture is worth a thousand words"........just don't mention which kind of words!

Larry Gibson