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At work over the years we have bought and sold surplus replacement parts for various types of machinery. Some of the parts dated from the 40's and 50's and had a hard sort of a slighttly opague finish that doesn't come off with solvent, or allow any rust. I've spent some time off and on trying to figureout what it was over the last couple years and finally in a chance encounter with an old fella that worked machining parts for slurry pumps I finally got some clues.
He said they would clean and degrease the parts, then coat them with some Cosmoline which they had thinned down with Kerosene. After the excess had dripped off they would bake them in an oven at 525-550F for a couple hours. Apparently the heat drives off any residual moisture and bakes the Cosmo on hard.
So I made some more tee nuts recently and figured they might be good to experiment on. I didn't have any legit Cosmoline, but I did have some LPS 3 which shares some distillates and parafin bases so I thought I would give it a try. I degreased, bead blasted and dried the parts, sprayed on a good coat of LPS and blew the excess off with light compressed air. Put them in the heat treat furnace at work and waited a couple hours.
The result looks similar to what I used to see, maybe a bit lighter in color, but is unaffected by solvent and is even tough to come off with emery. Now obviously this might not be a good idea for heat treated steels with a low draw down temp, but for everything else you just don't want to rust, it might be the ticket.
I plan to try it at lower temps and see if the result is the same. If it is, then even heat treated items would be fair game.
He said they would clean and degrease the parts, then coat them with some Cosmoline which they had thinned down with Kerosene. After the excess had dripped off they would bake them in an oven at 525-550F for a couple hours. Apparently the heat drives off any residual moisture and bakes the Cosmo on hard.
So I made some more tee nuts recently and figured they might be good to experiment on. I didn't have any legit Cosmoline, but I did have some LPS 3 which shares some distillates and parafin bases so I thought I would give it a try. I degreased, bead blasted and dried the parts, sprayed on a good coat of LPS and blew the excess off with light compressed air. Put them in the heat treat furnace at work and waited a couple hours.
The result looks similar to what I used to see, maybe a bit lighter in color, but is unaffected by solvent and is even tough to come off with emery. Now obviously this might not be a good idea for heat treated steels with a low draw down temp, but for everything else you just don't want to rust, it might be the ticket.
I plan to try it at lower temps and see if the result is the same. If it is, then even heat treated items would be fair game.
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