Bluing steel

[tinglett]

I'll post here under help because I have a disaster on my hands so far .

Fortunately, I was smart enough to try bluing for the first time on a scrap of hot rolled steel.  I started with a plate that was reasonably polished up.  I didn't have the energy to make it perfect toward the edges, but I thought it would be interesting to see how the bluing process handled scratches anyway.

Here's a picture of the test piece so you can get idea how it started.  I sanded it down to 600 and buffed it some.


Here's the stuff I was using.  Birchwood Perma Blue, and acetone for cleaning.  I had neoprene gloves to keep my fingers off the test piece, and used my cell phone as timer and camera.  I also had a little pail of water for rinsing the part after applying the bluing.


Here was my first shot at it.  I flooded it pretty good with a cotton ball and worked it for a full minute.  I had planned to go only 30 seconds, but it hadn't darkened the metal out to the edge in that amount of time.   Icky blotchy.   Right now I was very happy I wasn't looking at the pip-squeak engine I had just finished!


Here's after coat #2.  This was applied for 30 seconds.  The blotchiness is just moving around.


Coat #3.  No change.   I wiped with acetone and let it completely dry.  No help.


I flipped it over.  I was wondering if it was buffed up too much, so I hit it with a green pad to get this even spread of scratches.


Mr. Yuck.  It appears I have fingerprints here, but not sure where they would come from.  I had scrubbed well with the acetone so if they are prints, they are probably not from oil.


Another coat did little to help.


Here's a third coat.  My conclusion is that buffed finish vs. green pad finish didn't make much difference.


I noticed that I got a darker finish when I pressed the cotton ball.  For giggles I decided to apply with a bit of green pad.  It actually worked well and produced a much more even finish, but it also scrubbed it so the finish was a very light gray as can be seen in this photo.


Another coat added blotch again.  Sigh.


I decided to apply by scrubbing with a bit of cloth.  This worked much better than anything so far.


Here's the addition of another coat using the cloth.  Ick.


My conclusion so far is that this stuff is staying far away from my engine.

Todd

[AOG]

I had similer problems when I was blueing my elmers fancy. I turns out there was a residue that acetone didn't take out. I ended up scrubbing my parts with dish washing liquid and then soaking them them in a number 10 can of alcohol for an hour before I got them clean enough to blue evenly.  The other thing is that I am not a fan of the perma blue. Besides not likeing the color (more black then blue) I think it is more sensitive to contaminants. I like their presto mag better.

Tony

[Arbalest]

I've used that gun blue to good effect on stuff that has been sand blasted and it worked well.

Some observations.

The item to be blacked must be super clean all over, so you can't clean or handle the part with your bare hands. Use clean rubber gloves.

Hot items blue better than cold ones so once you've cleaned the part run it under a very hot tap for a little while to heat it up. If you want to be really picky you could drop it in hot deionised water but I've not needed to.

Immerse the part completely in a small tray of gun blue if you can, it will blue better than swabbing it with cotton balls.

Hope this helps.

[Jeff Michel]

You may want to consider having a local gunsmith drop it in his tank the next time he would run a batch of guns. It probably won't cost very much since you have done the polishing. Your finish or the quality thereof is based solely on the finish of the base steel. Black oxide or cold blue for that matter will not cover any surface imperfections. The higher the polish, the more obvious the scratches. For my tastes,  I run my pieces through a bead blaster then dump them into a bluing tank, the resulting finish is a smooth matte that holds oil well ( to retard rust) and the bead blasting removes all scratches and any residual oils on the surface. You can try applying your cold blue with a piece of degreased steel wool (0000), you will want to rub it firmly, initially you will be practically removing the previous application, stay with it and it will blue, sort of. You will still have some mottling unfortunately, nature of the beast. No oil, no bare hands while you're doing this. I usually restrict cold blue to screw heads, as indicated prior, dipping small parts are more effective than blobbing with a Qtip. if your interested in various bluing processes, contact Brownell's  at their  web sight, they can supply all sorts of information free for the asking. Good Luck.

[Arbalest]

If you want to treat larger items it may be worth getting a kit, this company is in the UK but perhaps similar kits are available over there?

http://www.caswelleurope.co.uk/black-oxide-parkerizing

[Danny M2Z]

G'day.

Try these guys. Here is a little video regarding blueing that you may find helpful. http://www.brownells.com/.aspx/lid=11050/GunTechdetail/Introduction-to-Cold-Blue-Finishes

Regards * Danny M *

[Dave Otto]

I have had good luck with the Brownells OXPHO-BLUE. I agree that there are probably contaminates that that a solvent like Acetone won't touch and that a good water based caustic cleaner will. I have only used water based cleaners on the small parts that I have done.

Also as others have indicated it works better if you can submerge the part, opposed to applying the chemical with a swab or cotton ball. The finish still going to be pretty much black and if you want a nice pretty blue you will most likely have to do it with heat.

Dave

[tinglett]

Thanks for all the advice!

Perhaps I should have purchased the kit from Birchwood.  It had a rust/blue remover that I was certain I wouldn't need, but it did have a cleaner that may be better than acetone.  Of course they never really tell you what goop they put in those bottles, so I thought I'd start with something I know -- like acetone.

This morning I scrubbed it hard with acetone with my neoprene gloves on.  I took another shot at it with 0000 steel wool and this worked incredibly well.  I used a cotton ball to get some of the chemical onto the steel, then used the steel wool for 30 seconds.  It scrubbed up some very black rust, but this quickly rinsed away in the water bath.  Still, the finish was fairly even compared to yesterday, but not black or blue.  It's a medium gray.  Not bad, but not really what I was looking for.


Next, I dried it off well and put it on a hot plate for a while.   It was hotter than I expected, but I was able to work with it provided I didn't hold it long .  The main problem was that the chemical evaporated pretty quick.  It didn't get darker with the cotton ball, so I tried the steel wool.  No real change in darkness.   It came out a bit more sloppy because it was hot...which is a statement of me being a bit sloppy.

Here it is sitting on a white paper.  I included a black sharpie marker for a little contrast.  It's not as black as the camera makes it appear to be.  The photo above is closer to reality.


Again, thanks for the help.  Maybe I'll use this for another project where a gray finish is ok.  In my particular engine I was looking for high contrast with the brass.  This isn't bad, but the shiny steel looks pretty good as-is.

Todd

[Dave Otto]

That does look better Todd,

One thing to consider is the steel wool may have oil, or some sort of stuff on it to keep it from rusting; this could be transferred to your part and cause problems with the finish.

Dave

[Arbalest]

I've found that with the Birchwood Cassey stuff it's a one shot deal, trying to get it darker by repeated treatment didn't work for me.
If I want to re-blue something I strip the old finish off first then heat and dunk the part as I mentioned before. You can get a really deep black by sandblasting the part first. Polished parts look nice heat blued and once dipped in oil whilst it's still hot is quite durable I've found.

[tinglett]

Thanks for all the hints everyone.  I certainly am "better" at doing this already, but nowhere near good enough to work on a real part.  It makes me wonder how many gun finishes are trashed by do-it-yourself-ers.

Speaking of guns, it occurred to me that my local Gander Mountain would have gun blue.  This is a big chain of sporting goods stores in the U.S.  I looked online and sure enough, they do, except they listed the same Birchwood Casey brand.   I went to the store anyway and found the stuff in the gun cleaning aisle.  It was the only brand they had, but I noticed that they had "Super Blue" which claimed it was super-strong and could make black on the toughest metals.

Well, here's what I got.  It was identical to Perma Blue.  I also tried on a little scrap of cold rolled steel, as well as on a failed part from this particular engine build.  It isn't terrible, but the buffed up steel looks much better so I think I'll stay away from blue until I have a serious reason to try it.  Even then, I'll probably look for a local gunsmith.  By the way, this picture is much more faithful to the shade of gray I'm getting.


Thanks again for all the help!

Todd

[Jeff Michel]

That looks pretty good for a cold blue. When you apply oil, wait a day then use straight mineral oil. Never use anything containing silicone on blued surfaces. It raises hob with any future efforts to blue (black oxide mostly) Most people used silicone bearing lubricants on firearms and they are pretty tedious propositions when it comes time to reblue them. I haven't found a solvent yet that will remove it. I've always had to remove it mechanically (buffing/blasting) It will come out of the tanks a marvelous muddy green/orange.