Broke the code on cold blue (Pre-15)

[xsexcess]

Picked up an early 1955 38 Combat Masterpiece from a LPS this week. I'd glanced at it several times over a couple of months, but after pulling from the counter and seeing it was a 5 screw I reached for the wallet. A few interesting details, and what I learned about cold blue follows.

First, the gun; pretty nice shape, $400 plus tax. Pretty happy so far. Not a smidge of rust on it, but a few worn blue spots in the usual holster wear places. Worn magna grips with wrong numbers, but checkering lines still there to follow to re-cut them (have done this several times). It's a 5-screw, LH thread ejector rod, finely checkered hammer (semi-combat), grooved narrow trigger. 4" bbl. The bluing actually has a 'blue' color to it. Quite beautiful, except for the worn bluing spots.

I consider blue touch-up 'maintenance' (others may consider this taboo). I've tried cold blue (Brownell's Dicropan in this case, but I've also used Oxphoblue and several others) in the past and never been satisfied with the results. The blue was always thin, not the correct matching dark color. In sunlight, you can see the difference.

So I read around the net and added a new step (for me) to my 'maintenance' routine. The new step was boiling water. My new process is;

Prep surface (finish isn't going to match if the metal itself isn't the same surface roughness, sheen, as the area around the repair). If it's matte, use fine 3m pad and make it rough. If it's gloss, use fine grit automotive 'polish' (finer than 'compound') and polish it.

Immerse in or ladle with boiling water for a minute or two. This is the key. The boiling water changes the molecular structure of the microscopic rust that's there, even though you can't see it. Cold blue can't work properly until the microscopic rust is converted.

Clean with isopropyl alcohol.

Heat with a heat gun (cheap pawn store one is fine) until the bluing compound nearly sizzles (or just barely does).

Scuff with 0000 steel wool.

Repeat the alcohol / bluing compound / scuff until you're happy with the color. 3-4 times for a S&W barrel worked for me.

Oil it up well.

Enjoy!

And, if it has small rust spots/pits, use a cheap mechanical pencil to dither the orange rust away. The 'lead' is harder than the rust, but softer than the steel. Nice small diameter gives a lot of control. Forget about trying to use a wad of steel wool or abrasive pad to get into the pits.

Hope this is useful to my fellow accumulators. Maybe the true old-timers already knew this, but it was a revelation to me.

 

[Hondo44]

Thank you for that. This might help some as well:

How to determine which cold blue is the best for you.

See Various BLUING Products tested here: Evaluation of several cold bluing products (w/pics) - 24hourcampfire

 

[DWalt]

I came into a fairly sad condition (extensive holster wear and some rust) Model 15 several months ago at a very good price. I went over it with copper wool and light oil to remove all the rust I could (fortunately it was not badly pitted or rust freckled), then I thoroughly degreased it with mineral spirits and acetone. I applied Brownell's Oxypho Blue, and it turned out very well indeed. The Oxypho Blue blended into the remaining original bluing almost indistinguishably. From more than a few feet away it looks very good.

Back when rust bluing was in vogue, the metal was rusted and carded, then boiled in water. The boiling converts the FeO to Fe3O4 (Magnetite).

 

[Hondo44]

Picked up an early 1955 38 Combat Masterpiece from a LPS this week.

It's a 5-screw, LH thread ejector rod, finely checkered hammer (semi-combat), grooved narrow trigger. 4" bbl. The bluing actually has a 'blue' color to it. Quite beautiful, except for the worn bluing spots.

That gun is about 4 years too early for the thread change from RH which was the Model 15-1 in 1959.

Are you sure the extractor rod is left hand thread?

If it truly is, I suspect a cyl change.

Is there a matching serial # on the rear face of the cyl?
Or a star following the serial # on the butt and a date on the left side of the grip frame under the grip?

 

[xsexcess]

Jim, thanks for the reply. The serial is present on underside of bbl, but not on rear of the cylinder, so you are likely correct the cylinder could have been replaced. Knurling on the ejector rod has had the typical pliers tightening damage, so I removed it to verify thread and length. I was surprised it's not right handed threads (pleased really, easier to find). You're expertise is amazing to pick up on that. Other than the 5 screws and less aggressive checkering on the hammer, it looks pretty conventional to me. Amazing that the adjustable sight introduced just after the war has not needed to be changed.

Under grip on the L side there is a small 9 space 64 stamp, and a diamond on the same side.

The older Smiths I find here in N Texas almost always have at least some minor corrosion pits under the grip panels, but this one is totally clean...makes me wonder where it came from. W Texas, NM, AZ?

 

[xsexcess]

Serial BTW is K 25797X in case you're trying to track when the 5 screw was dropped. Based on the Std Catalog, production should be sometime early 1955.

 

[gman51]

I used Casey's cold blue touch up on my Python holster worn cylinder areas and it came out looking fairly good.

 

[Gunhacker]

The process you describe is akin to rust bluing, with the boiling in water to convert the red oxide to black oxide.

Years ago, I used that method to blue an "in the white" steel grip frame, using Brownells Oxpho Blue, that I fitted to my Old Model Ruger Blackhawk.

I got a deep luster blue that has been as tough as a hot blue.

 

[Old Corp]

Good post, and one I nearly started myself....

Recently got a M57 6" off GB at a fairly decent price due to finish issues.
Most of the gun was fine, just the last ~3" of barrel looked like it'd been stored in a wet holster or similar.

Nearly all the blue gone in that area and pits evident, but someone had done a pretty good job of getting rid of nearly all rust that had obviously been there.
Unfortunately, there is no good 'Pit-Be-Gone' on the market.

Acetoned the area really good.
Went after it with some light oil and fine bronze wool. Saw a tiny bit of remaining rust go away.
Acetoned again.
Heated with a heat gun set on low and got the area quite warm, probably just shy of 'sizzle' in contact with liquid.

Four (4) applications of Brownell's Oxpho Blue while hot, re-heating a bit between applications.

When the color-tone came to closely match the factory color, I wiped it down with basic gun oil, stopping the process.

Yes, the little pits still exist, but I was really pleased with the final result.
This will be a woods and hunting gun, so pristine was never the goal.

My first use of Oxpho Blue and was quite surprised at how close it came to matching up to the S&W blued finish.

Thanks for a good, informative post.

 

[Hondo44]

Jim, thanks for the reply. The serial is present on underside of bbl, but not on rear of the cylinder, so you are likely correct the cylinder could have been replaced. Knurling on the ejector rod has had the typical pliers tightening damage, so I removed it to verify thread and length. I was surprised it's not right handed threads (pleased really, easier to find). You're expertise is amazing to pick up on that. Other than the 5 screws and less aggressive checkering on the hammer, it looks pretty conventional to me. Amazing that the adjustable sight introduced just after the war has not needed to be changed.

Under grip on the L side there is a small 9 space 64 stamp, and a diamond on the same side.

The Sept 1964 on the grip frame is good news. The cyl was changed at the factory. After ~1957 barrels and cyls were no longer serial numbered because the "soft fitting" process was eliminated, and that includes un-numbered replaced barrels and cyls. Also we seldom see the star on the butt after the 1957 period when guns were returned to the factory for rework or refinishing.

On 5 screw guns you will find the s/n on the back of the extractor star (except yours now of course), and the rear facing side of the yoke looking thru a chamber with a flashlight.

In my experience, the post war sights last the life of the gun. Most usual only reason for a change is a dropped gun.

Thx for the bluing tips and enjoy your prize find!

 

[DWalt]

I don't know if it still exists, but there was once a cold blue called "44-40" which was very good. I "sporterized" a fairly beat-up '98 Mauser back in the late 1950s, polished the metal and blued it with 44-40, and that was the first experience I had with cold bluing. It looked very good. Chemically, the cold blue finishes are nothing like those produced by hot bluing or rust bluing so they are not as durable.

For any type of bluing, the use of acetone or MEK (chemically very similar to acetone) for parts degreasing is highly recommended. When we were bluing M9s at the USAF gunsmith shop, we quit boiling parts to be hot blued in a silicate detergent bath to degrease them. A good wipedown with MEK and paper towels achieved better results. Best done outside as MEK is fairly flammable.

 

[dr. mordo]

We need pics!!!!

 

[Hondo44]

I don't know if it still exists, but there was once a cold blue called "44-40" which was very good. I "sporterized" a fairly beat-up '98 Mauser back in the late 1950s, polished the metal and blued it with 44-40, and that was the first experience I had with cold bluing. It looked very good. Chemically, the cold blue finishes are nothing like those produced by hot bluing or rust bluing so they are not as durable.

For any type of bluing, the use of acetone or MEK (chemically very similar to acetone) for parts degreasing is highly recommended. When we were bluing M9s at the USAF gunsmith shop, we quit boiling parts to be hot blued in a silicate detergent bath to degrease them. A good wipedown with MEK and paper towels achieved better results. Best done outside as MEK is fairly flammable.

Thanks for the MEK suggestion.

I found 44-40 a very inferior product many years ago. The smell was far more durable than the blue finish. And it was an easy way to detect touched up firearms it had been used on.

You'll be much happier with the top ranking two products tested in the link in my post #2: OxPho blue and Nu Blue, especially when used as described by the OP.

 

[Gunhacker]

I don't know if it still exists, but there was once a cold blue called "44-40" which was very good.

Brownells acquired the formula and is selling 44/40...

BROWNELLS FORMULA 44/40(R) INSTANT GUN BLUE | Brownells