best blueing product or formula for polished clean parts?

[coppercone2]

I am looking to blue some machine tools that have been completely polished with abrasive and degreased with a ultrasonic.

I see they sell certain types of blues that are designed for dirty guns in mind that go through the oil and stuff, but these things I am working with are expensive and simple geometries (not gun pipework)..

I don't mind buying a few chemicals and mixing stuff up carefully if its cheaper.. has anyone found that commercial products are superior in terms of trade ingredients or something? I would like the geometry to stay precise. Say for V-blocks, machinist vise, etc.

Also, what are the limits of coating thinness and usability in terms of doing something like coating a micrometer base stand with bluing compound?

I had this product in mind : https://www.brownells.com/gunsmith-tools-supplies/metal-prep-coloring/metal-bluing/liquid-cold-bluing-chemicals/super-blue-prod24770.aspx


Or any alternatives which are suitable, like electroless nickle plating, etc. Stuff I can smear or soak.

[KL27x]

Cold blue is selenium dioxide. Regardless what the brand on the label says, it is probably going to be just the same. Works better if you warm it up.

For durability, parkerizing is way better, IMO. It will add a tiny bit of size to your parts, but in this case it will not matter. It's applied the same way only you need higher temp and/or more time. But it doesn't take that well if you polish the parts too fine.

Also, what are the limits of coating thinness and usability in terms of doing something like coating a micrometer base stand with bluing compound?

If it's flat as flat, and used on a flat surface plate, even selenium blue will hold up for a good while. Keep it oiled. If the finish wears through in spots, those spots are going to be super polished/burnished from the sliding/wear, and they won't rust, anyway. But degrease and reapply to the spots that wear away, and you will eventually have full coverage.

[coppercone2]

What product is good for parkerizing?

I see that even with the rub on blues there is a HUGE difference in usability, the blue I linked seems to just work, whereas the other blue from the same manufacturer takes like 6 applications, at least on some steel

It seems that generally the bluing compounds add less then 0.0001 inches to the part. Are all of them going to be the same?

I don't want to buy a parkerizing product and be left with the 'non result' from the video.

[coppercone2]

is there a good website that shows side by side comparisons of the same object coated with different methods?

[KL27x]

Yeah, selenium dioxide is very thin. And IME, it will eventually wear off even from rubbing against the skin of your hands. But it's better than the array of weird colors that steel will take on its own, and it holds some oil while it's there. On a highly polished part, a spot that gets rubbed will get lighter and lighter until it's essentially naked. It won't be a sudden bare patch, so it's good for this type of thing.

You can make your own parkerizing solution by dissolving zinc in phosphoric acid. But for small parts, it's cheap enough just to buy it in a bottle from Brownells.

For small parts, just put it in a baking tin and shoot it with a heat gun or use a gentle flame.

is there a good website that shows side by side comparisons of the same object coated with different methods?

The final color depends on a lot of factors. The type of steel and the surface finish before coating, primarily. But even the kind of oil you use on the part can end up changing the color over time. With any of these oxide coatings, you can expect to get some splotchiness on a highly polished part. It's easier to get a good finish after a higher grit sanding or sand blasting. But on the super polished part, I would just keep reapplying it until it looks right.

There's zinc park and manganese park. Zinc is a thinner, slightly smoother layer. It will usuallly end up anything from light grey to dark blue and any mix in between. Manganese ends up very dark grey to black. The manganese ends up like 4x thicker or more, but I think zinc is just as durable. I think it's supposed to be more durable, actually. I want to say zinc can add around a thous, but I could be way off.

I don't have access to a sand blaster. I've had good success parkerizing steel parts with a 400 grit hand sanded finish, if memory serves. You can't even tell they've been refinished from a foot away, and it is durable.

[coppercone2]

I have gotten the super blue for initial experiments and will get the parkerizing solution in the future

If it is anything like the surface that rust remover phosphoric acid leaves, I will prefer the smoother one most likely but it seems worthy of an experiment. I find naval jelly finish quite offensive to my hands.

I believe my precision side cutters and pliers etc are selenium blued (mostly swanstrom). It is nice.

Does the parkerization finish hold up better to high temperatures, i.e. stuff used around welding ? Is this the coating that the old hand vices from GDR have? It seems particularly robust when used to hold end bits of welding rod.

[eKretz]

Cold blue is crap. It will rub off if it is handled at all. Quality bluing is a high temperature process and totally different than cold bluing - and far more durable. It can be done at home but it is far more hazardous, and caustic chemicals are involved. I can pretty much guarantee that any high quality tools are not selenium blued. Personally, for small scale at home work I prefer rust bluing.

[coppercone2]

is that something you could do.. to a caliper?

[KL27x]

If it is anything like the surface that rust remover phosphoric acid leaves, I will prefer the smoother one most likely but it seems worthy of an experiment.

parkerizing leaves a surface a bit like that. But it will smooth out over time/use.

Does the parkerization finish hold up better to high temperatures, i.e. stuff used around welding ? Is this the coating that the old hand vices from GDR have? It seems particularly robust when used to hold end bits of welding rod.

Don't know.

Personally, for small scale at home work I prefer rust bluing.

Interesting. I have a firearm that is rust blued. It's a deep chocolate brown with a hint of eggplant to it. The gun is older than I am. I have read how it is done, and it sounds easy enough, if you have the patience. Essentially it seems no different than hitting a part with a wire wheel after it rusts, except you make it rust, intentionally, and keep going until you have 100% coverage. And you use a fine wire brush by hand.

Whenever I get little spots of surface rust on a smooth part, I might oil and stone away the red/orange stuff with a small bit of translucent arkansas stone on a stick. The idea is to leave dark oxide in any low spots/scratches and to polish away the high spots. Even though the swirl marks from the stone are obvious, they are extremely shallow, finer than 3000 grit sandpaper, so it leaves a water repellent surface. And any shallow scratches that the stone doesn't reach retain oxide/oil and also repel water. Eventually the thing reaches equilibrium where it stops rusting, yet the bearing surface remains smooth and unfinished. This takes a long time before it stops looking like crap, if you keep it purely practical. And it looks nothing like rust/card bluing.

If you apply a regular pattern of overlapping circles over the entire surface and intentionally apply a patina after the stoning, it will look pretty decent and remain totally smooth. Any low spots or areas of deeper scratches will become dark and obvious, these spots appearing "out of nowhere," and the rest of the part will remain bright, but the swirl marks will get muted/blended after long enough in the acid. This gives a "natural" patina in the sense it forms where it naturally wants to and areas that are completely smooth with not pick up stain. The spots that are left is what you live with rather than trying to polish out every scratch and putting the thing in a museum.

[eKretz]

There are several different versions of rust bluing. Probably hundreds of different recipes for the rust accelerant. A brownish finish or a black finish can be produced. If you want the brownish surface you do most everything the same as if you want a black surface - except between "rustings" you immerse the workpiece in boiling water or expose it to high temperature steam for several minutes if you want a black finish. This converts the red iron oxide to the black version. This entire process (rust, card, boil - or not, rust, card, boil - or not) is repeated multiple times and will get darker the more times it's done. It's much more durable than cold blue.

[coppercone2]

if a surface is flat, and coated with the ultra thin selenium based one, does a glass inferometer lens still work on it? does it need to be shiney?

Also, is there good cheap solutions to build a inferometer illuminator? Do I need helium or can something be put together with a stable power supply and diodes? are there better colors then yellow? I see people talking about using green lasers but it seems weird.

[eKretz]

When you say interferometer, I think you mean optical flat? Those are more likely to be used with specific wavelengths (colors) of light in my experience. The blued surface should have no effect on that process, and shiny or not doesn't make a difference.

If you really mean interferometer, shouldn't be a problem for that either.

[coppercone2]

hmm, so I need a yellow laser? yes optical flats, west german

[coppercone2]

when used by a flourescent bulb, on a flat surface, you get a very weak pattern that looks orangeish. I assume you need orange light then?

[coppercone2]

is granite surface plate wear effected by cold blued parts ?

[coppercone2]

works very well for the effort applied, there does not seem to be any fit or other problems with anything. I will try some shafts with it.

[KL27x]

is granite surface plate wear effected by cold blued parts ?

If the stand is flat and the plate is flat and wiped clean, there is no wear to the surface plate. Your surface plate will suffer wear when you drag parts across is that are not flat and/or have burrs.

[eKretz]

You want a monochromatic light source for use with an optical flat. Doesn't matter if it's a laser or not. Popular choices are often helium lamps or sodium lamps.

Re: the orange colored pattern - the light source will create differing color shifts depending on wavelength and spectra present. A full spectrum white light source will produce a rainbow color pattern.

[coppercone2]

did a great job making caliper graduations readable again

[eKretz]

Just ran across an old straight that I rust blued last year. This will give some idea of how it looks when done to achieve the black finish.

[coppercone2]

Just ran across an old straight that I rust blued last year. This will give some idea of how it looks when done to achieve the black finish.

are you sure you want to rub selenium on your face? I figure it will react with shave gel

I had alot of fun restoring old strait razors from estate sale, but I do not want that on my body. I like vibrating gillete blades. Best use of AAA battery ever.

[eKretz]

There is no selenium. It's rust blued.