Surface prep question?

[G.T.]

Hello to all, I have a question for all the restoration and/or refinish guys that have had to battle some tough finish removal in the past!... I have stripped finish with chemicals, and also the old fashioned way with sand paper and /or wire wheels and steel wool. The problem with the above, they are all time consuming, usually alter the surface, and are also expensive, not to mention messy most of the time.
My question is more geared to the members that use sand or glass bead blasters? I have a very talented friend from the aircraft industry back ground recently inform me that for the delicate projects they use Industrial grade Sodium Bicarbonate (Baking Soda) instead of the more course media more frequently/previously used... So here's the main query on the subject, have any of you fellows ever used it, and will it remove blue or black oxide finishes?... Walnut shell is another medium that would be interesting to try? But probably lacks the aggressiveness to defeat the different finish types.. If you know, let me know!....... best to all, til...lat'r....GT

[DonVoigt]

GT,
any abrasive will remove black oxide. It is only on the surface.
Baking soda is quite mild, but will still leave a matte finish.
Walnut shells come in different grades, and can be quite aggressive, more so even than glass beads!
Fine glass beads are a good option too; worn out glass beads are even better for some projects.

I have used sand, glass beads, zirconium oxide beads, and walnut shells myself; but not baking soda.
Baking soda would have the added benefit of completely washing away with water.

[Edward Tinker]

My son and I actually looked at a baking soda cleaner (industrial) for a side business but decided against it, but we liked everything we heard.

I do think that any blasting will likely leave a different finish than sanding.

I think someone told me that if you do sand, don't use above 300 grit? That 600 and above will look like glass.

ed

[mrerick]

Count on at least a couple of mechanisms when you try various chemicals, additives and abrasives. Chemical conversion and actual abrasion. Polishing stones useful for flat surfaces.

Both can be aggressive or mild, fast or slow, but in any case I expect quality is time consuming.

It's likely that overall processes can accomplish better control through chemical conversion techniques.

Bead blasting techniques will leave a matted surface. Sanding will leave abrasion marks.

The bead blasting techniques will be reasonably random and uniform. Polishing out a surface prepared this way may, in the end, be easier because there will be fewer identifiable marks. But... the entire surface will need to be uniformly polished. That is also difficult and time consuming.

[Vlim]

Cat pee works great. Don't ask how I know.

[lugerholsterrepair]

Gerben, it's INSTANT blue removal! Blue to white in mere seconds. Watched it with my very own eyes, right out of the warm furry container.

[Vlim]

Since the main component of the fluid appears to be uric acid, I wonder if this is actually useful as a de-bluing agent without employing a cat. I understood its also a basic ingredient for women's make-up, especially in skin creams.

Brings me to the question: is skin cream useable as a debluing agent?

[G.T.]

Ok Vlim and Jerry, as much as I appreciate your input, I'm not going to get caught squeezing cats over these drum magazines.... .... Although there is an ample supply of feral urban felines, and I do like your train of thought, both my German Sheppard and wife, say no! So, I'm going to try the blast cabinet and see what medium works the best? I have to do extensive masking as well as there are only a few interior spots that need treatment and polishing... Abrasives hand held, are too labor intensive, too expensive and waaaay too slow! Best to all, til….lat'r.....GT

[HerrKaiser]

Well, if nothing else that reinforced my suspicion to keep my own cat away from my Lugers as much as I possibly can. I was originally more concerned about pet hair getting into the mechanism. Sorry Taco, I like the finish on my guns as is.

[mrerick]

The Thomas Register lists a source of Uric Acid chemicals:

https://www.thomasnet.com/profile/00...what=Uric+Acid

[Edward Tinker]

I bought a older S&W and the finish was awful, splotchy, etc. I took vinegar and filled up a plastic tub just large enough for the revolver, and put it in only minus the grips, waited overnight (I bet it could have been less and it was all gray. I think cleaned it, cold blued it and resold it. I just wanted it to look better. An actual reblue would have been best.

[Vlim]

Yes, a mild acidic solution should do the trick.
Wish I had spent more time in the physics lab.

Another problem is that if you order chemicals nowadays they immediately assume you either run a meth lab or a bomb factory...

[G.T.]

Hi to all, Chemicals would be nice, even with all the problems and precautions...but, I can't use liquids as I only need to address certain areas in the interior of each part, (can't tolerate drips and runs!) .... Masking and blasting seem to be the most promising, and maybe I can reduce masking time as I go along... ..... I am open to all ideas and suggestions... best to all, til….lat'r.....GT....