Fellas, I'm not a gunsmith by trade, but I did recently take on the job for a friend of cleaning up a couple of guns he was given that laid only 200 yds. from the Gulf shoreline for 6 wks. before they were brought out.
Amazingly, they're both going to clean up very well, believe it or not! If anyone else is doing something similar, I thought I'd pass on a couple of things I've found, and if anyone else has additional info or recommendations, I'd like to hear them. Maybe someone else will benefit from them too. I'm posting this because this type of cleanup is WAY past the routine cleaning we usually do on guns, and maybe what I've found may help someone else out there. A lot of sentimental favorites have been damaged, and maybe this'll help someone salvage at least a few of them?
First thing I found is that plain ol' liquid hand soap (mine's "Soft Soap" brand, I think it is) is the absolute BEST thing for cleaning out the gross rust that has accumulated. Just pour it on full strength without any water to get the worst of it off, and use hot water only too rinse it and the loosened rust off & out. Repeat until the pits don't have any more rust left in them. Works FAR better than the oil and steel wool that many usually use to brush off light flecks that can appear sometimes. A buddy who's familiar with such things says the fats in the soap (NOT detergent, BTW, which is a whole 'nother set of chemistry) help emulsify and lift the rust. Helps penetrate the porous rust, and maybe the lye (or whatever acid's involved) helps break it up. Combination sure does work better than anything I tried, I can tell you that.
The two guns I'm working on were immersed in salt water, so a GOOD and I mean REALLY good scrubbing in hot soapy water after knocking off the gross surface rust came next. This was to (hopefully) dissolve and remove the salts from the metal, in hopes of preventing re-rusting - a VERY important consideration. If you don't get the salt out, they'll just rust back. Water is salt's best solvent, and hot water does it better, quicker and more deeply than any sort of oils you may have on hand.
The remaining metal will have some pitted areas, and these can be a bit tougher to deal with than the softer surface rust that built up. Just use steel wool and/or a wire brush with the same liquid soap (again, NOT detergent) and keep pestering those tough spots until they finally give way. If you don't get them, you're spittin' in the wind, and the rust will just come back again, and eat even deeper pits into the metal.
I didn't have a metal container big enough to boil the big parts in, but boiling in soapy water would likely help, I think? Heat proofing gloves really help when handling hot metal, of course!
After getting the metal clean and de-rusted, there STILL may be some rust left hidden in tiny pores, pits and recesses. This needs to be chemically removed, I think. I haven't gotten this far with mine, yet, but I think I'm going to use some bluing remover for this part of the cleanup. Bluing is nothing more than black rust, basically, and anything that'll remove bluing will do the same for rust. Somebody correct me if I'm wrong here, but I think muriatic acid (phosphoric acid, isn't it?) can be used for this. I'm not sure if or how much it should be diluted with distilled water, so please someone, let me know about this if you will.
After getting all the rust I could out, I used some Semichrome metal polish, and got some more of it out that didn't show visibly - and it's the stuff that doesn't show up visibly that you're REALLY going to have to fight. After the Semichrome, I used Hoppe's to clean out the Semichrome, then clean swabbed that off, resoaped it and cleaned again down to bare metal. Then I used Marvel Mystery Oil, which is a very fine metal penetrating oil similar to Kroil but cheaper, and let that sit on the still warm metal so it could penetrate into any rust I couldn't see, and into the pores of the good metal. Then wiped that off, and applied Breakfree to preserve/protect the metal. This looks like all I'll need to do to most of the parts of the detail stripped guns, but some will require more cleanup. I think (?) I'm going to de-blue ALL the parts before I get them reblued.
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