From Rust to Salt Blue...
 

Hello,

What were the reasons for switching from Rust to Salt Blue in 1937 ??

Could the explanation be simply found in the word: PARABELLUM ??

From my limited knowledge, I do not think WAR was in the III Reich plans in 1937 ??

Top pistol: 1st Variant S Block Rust Blue, Strawed parts
Bottom pistol: 2nd Variant V Block Salt Blue

MARK :cool:
http://forums.lugerforum.com/lfupload/dscn1869.jpg http://forums.lugerforum.com/lfupload/dscn1873.jpg

Kidvett:

From what my father told me about the speaches that were relayed and played here in the states, Hitler was ready to start a war in the early 30s.

If you read his "Mein Kampf", you will see that his entire foreign policy was based on war as the method of acquisition of land for the Germans in the Slavic East.

As to your question regarding salt vs rust, please compare the time necessary for a proper job for both. This should answer your question.

Sieger

Mark,
I think that this could be stated better by "Thor", but I'll try.
Rust blue is a very tricky process that is very time and labor demanding, and also easily messed up. in addition it is not as tough as the salt blue process.
Tha Salt Blue process is to describe it in simple terms simply dipping the parts into a hot *Salt* solution for a few minutes, neutralizing it, steel woolbuffing and oiling.
Rust Blue Is accomplished by Lightly coating the parts with an *acid* solution and hanging in a temrrature and moisture controlled chamber until a rust coat is generated.
this is steel wool buffed and and recoated and returned to the chamber to repeat the process.
this is continued many times until the coating is satisfactory and the part is neutralized, dried, steel wool buffed and oiled.
*Salt* and *Acid* are Basically nitric acid and hydrochloric acids and the salts are nitrate salts.
Two exactly opposite approaches to obtaining an Nitrous Iron oxide coating as the surface of the steel. Nitre is the constituent that renders the oxide blue in color.
I apollogise for the poor explanation of a very complex subject.
But I think I have sucessfully described the relative complexity of the two processes and this explains why most modern guns are treated by processes that resemble the "Hot Dip Method"
ViggoG

I once posed the question to Thor, and he replied that rust blue is more durable than salt blue. This is borne out in my experience with guns so finished.

Aside from that, Viggo's assessment of salt blue being quicker, easier, and cheaper (and therefore more desirable for fast military production) is right on the money.

And Mark, thanks much for the visual comparison--it is quite illuminating.

--Dwight

Metal prep time is identical for both methods. After than, the actual bluing time is MUCH different. Salt bluing time is around 20 minutes while rust bluing usually takes 2-3 DAYS. Rust bluing goes deeper into the metal and does provide better wear and rust protection. Time and cost are the real reason they switched as previously noted. A modern day salt blue will appear really black and rust bluing will apear gray/blue in color. The rust bluing is much prettier to the eye IMO.

For a rust blue finish, some taking far less than 2-3 days, and with a minimal anount of equipment, one can reach Brownells at 1-800-741-0015, with a little steel wool and a hot water bath, a beautiful rust blue finish can be obtained with a varity of their products, try: Pilkington Classic American Rust blue, or Dicropan IM or Dicropan T-4, I use these on all soft soldered double barrels and once in a while on older classic rifles and hand guns...and free advice is alway available at Brownells at their tech section....its fun try it.

For a rust blue finish, some taking far less than 2-3 days, and with a minimal anount of equipment, one can reach Brownells at 1-800-741-0015, with a little steel wool and a hot water bath, a beautiful rust blue finish can be obtained with a varity of their products, try: Pilkington Classic American Rust blue, or Dicropan IM or Dicropan T-4, I use these on all soft soldered double barrels and once in a while on older classic rifles and hand guns...and free advice is alway available at Brownells at their tech section....its fun try it.

<img border="0" alt="[soapbox]" title="" src="graemlins/soapbox.gif" /> For ANY blue job, the quality of the metal preparation is the key to a poor, acceptable, or beautiful appearance. Removal of rust pits, and care to keep flat surfaces flat, not round edges and dimple screw holes is of paramount importance. The quality of the polish job will determine the quality of the blue job.

Most instructions for rust bluing guns recommend a minimum of 5-6 applications. I suppose that this could be accomplished in a 24 hr period, but I'm not going to attempt it. I have blued guns using Dichropan, it is my preferred product, because it can be done in an afternoon. But I don't believe it is as durable a finsh as Pilkingtons, which takes me a couple days to do right.

In my humble opinion, not everyone is equipped, either physically, mentally, or equipment wise, to do an outstanding blue job. Ted Green is one of those individuals who is so gifted!
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

Your correct....metal prep is everything, but lets don't discourage those who want to learn, from starting out somewhere....find and old discarded barrel and with a little patience try.
You will not know if your gifted until you try.

I had a great time and an enjoyable experience when I did my bit-up all matching Simson. I used the Pilkington Classic American Rust blue and it worked great. But, as already metioned by the experts, I spent most of my time preparing the gun/metal than applying the rust bluing. This was the same gun I posted about 8-9 months ago. I have pics if interested. Off course, my results are not comparable to Mr. green's work. But, it gave me an opportunity to appreciate the process.

Viggo, I would offer one correction to your excellent write up. Nitrate is not a necessary component of the blueing compound. I do not know if it is necessary to have nitrogen available to obtain the blue color. I have done a fair ammount of rust blueing with compounds not containing nitrogen (or nitrates) however the stuff we breath is loaded with it and I have never tried the process in a non-nitrogen containing atmosphere.

An excellent reference on the subject is R.H. Angier "Firearm Blueing and Browning" originally published in 1936. Angier says the rust originally formed is ferrous hydroxide which gradually converts to brown ferric oxide. This is converted, often by boiling, to more or less black "magnetic oxide" or ferro-ferric oxide.

Interesting thread......

Yea - I've used Brownells. They are just fine - for a home - hobbiest. However....

If you want a rust blue job that looks right, where the individual who does it knows what they are doing - for gawd's sake - send it to someone who knows what they are doing....

When you have oils impregnated in the pores of the surface - and your "rust home blue job" looks like crap - call Brownells, Know what they'll say?

As for me - I sent my slide to Thor 2 weeks ago - confident it will be done right. Is it worth it? Yes - only because I want a rust blue "without excuses".

Like "home strawing", "home rust bluing", home fix-its - you get what you "pay for".

Funny how that works, huh?

Not a Flame - but certainly the truth. Oh - and I've been both a tabletop Gunsmith and a "registered" Gunsmith. I started over 30 years ago.... You want "OK" - it's DIY. You want "professional" - find a Professional. I chose to use Ted - even for a pistol I built 20 years ago. I wanted a "Professional" blue...

As an FYI - Rust Blue isn't a "home project" - unless you want "OK, I can love this - but crap - I hope I don't ever have to re-sell it...".... Ask me how I know....

All,
* Mark: Thank you for your comparison pictures.
* I'd suggest this be placed in the Forum's Tech section for reference between rust vs salt vs post WWII Luger bluing comparisons by learning/interested parties.
* 1937 was an volatile year for P.08 changes by Mauser. In addition to the bluing change depicted above, the Mauser Frame hump became standard. Also, the droop eagle acceptance marks became stick eagle. Essentially the straw parts became blued with the introduction of the Salt blued 2nd Var. But, and I may be mistaken here, I believe some legitimate 1937 P.08's had straw parts over a salt blue and (possibly) vice versa as Mauser used up bin parts during the limited transition range. Have the S/N blocks or close ranges been uniquely identified/updated for these 3 or 4 separate transitions? What ranges are y'all using?
* Paranthetically, the original matching mags for these 1937 pistols had a droop eagle/63 to stick eagle/63 transition in the Q-R block I'm told.
Thanks,
Bob

Heinz,
I would refer you to Angiers, "Firearm Blueing and Browning" p.96-97. of the volume that you reference.
A description of the Springfield Armoury browne process.
As far as I can determine these are the closest processes he describes that are similar to the Early German Rust Blue used on the Luger Pistols.
In each of the Springfield Armoury formulas I find the use of "Nitric Acid" and/or "Spirit of Nitre".
Out here in the backwoods of Va. there are very few if any "Industrial Chemists", so I turned to our local Pharmacist who has a background in Organic and In Organic Chemistry,
To my best understanding, He recommended that I experiment with making slight changes in these two constituents to influence the color quality.
My experience demonstrated that his point had value. He gave me the feeling that Nitre was a contributing factor in the rust blue process.
I'll not disclose more on this subject as I consider my work to be proprietary in the same manner as Thor.
I was not then, and am not now, interested in discussing the details of the Blueing Process.
I was simply attempting to answer a question and quickly describe in easy to understand, "if inexact", language, the similarities and differences of processes that have had many volumes written on the subject, and most still fall short of being clear to the casual reader.
If you are one of those who really understands Angier, you have my congratulations, "His work is very hard to follow".
Please forgive my inadvertent error in a poor choice of words in trying to simplify such a complex subject.
ViggoG

Thor, do you do your own rust and salt bluing or do you 'farm' it out ? Just wondering.....

Daniel I do all my own rust bluing and salt bluing at my shop.

This is all been great, I was just feeling that if inside you, you feel you are not all you want to be...reach out and try. I just finished a baby Nambu, its beautiful, something I would not have attempted 20 years ago. If it is in you to reach out and try some this, do it, start slow and on replaceable junk guns...we all had to start somewhere. After 30 years at it I am at the point either hire another gun smith, or just start turning down work...and it all started with a shooter 1920 Luger I want to rebuild my self, and an old gunsmith who want to teach.

If I had an expensive piece and I did not know what I was doing or was afraid to try, I would send it out too. However, you have to remember that every professional started as an amateur. Only through trying do you gain the knowledge and experience. You'll either find that you have the talent, or at worst, that you had a great time trying it.

Viggo, Please check your private mail.

regards, heinz

Heinz,
I'm taking this opportunity to openly answer your PM to me.
I do this so that every reader can be certain that our messages are open to all.
&gt;&gt;&gt;
I'm very sorry that you interpeted my reply as an answer to insult.
Quote " Please accept my apologies if you found my comment out of line."
Under the circumstance there is absolutely no apology that could be acceptable,
Ha Ha Ha, Gotcha there,
Because there was nothing at all for me to take eception to.
In as much as the majority of my information comes from "my Q" and "their A", I do ask a lot of questions and quite a often at that.
Perhaps I had seemed to read into your posted reply quoting Angier, that you may not have been familair with his brief passage on the Smithfield Process.
Forty years ago I was fairly active as a FFL Gunsmith, and as my work responsibilities at NACA / NASA increased I was forced to wean myself away from it all.
And In as much as this brief article has been the source of much of the blueing process information that I have obtained in the last 30 years, along with the assistance of my Pharmacist friend, it was the total basis for my particular wording in my first post, and following your post,
I was hopeful that I would not inadvertently say something that would be interpeted as an insult to you.
I thank you for your comments and I certainly have NOT TAKEN INSULT from your posts.
I found your comments absolutly appropriate and I was hopeful that I would not ruffle your feathers.
Thanks for the kind thought as to my feelings. My friend.
ViggoG

Heinz & Viggo,

<img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" /> I don't know why I have a perverse desire to get into the middle of this, but this information may be of help to those interested.

Quoted from INTRODUCTION TO MODERN GUNSMITHING by Harold E. Macfarland, pages 235 & 236, discussing rust bluing:

"The object of any bluing process is to oxidize the surface of the steel with a minimum of the common red or brown oxide known as ferric oxide, or rust, and with a preponderance of the desired black ferrosic oxide. This is a black magnetic sesquioxide. It occurs in nature as "black sand" and is commonly found in connection with placer gold. Ferrosic oxide is impervious to rust. Surfaces so blued will subsequently rust only because the film is non-continuous, "porous". Hence a high degree of polishing on the steel surface is indicated, since it helps prevent rust by making the film continuous.

Essentially, the desired ferrosic oxide is formed by nitrogen compounds. Sodium nitrate is commonly used. Potassium nitrate is more desirable for several reasons, but more expensive. Ammonium nitrate is sometimes recommended but should be avoided, since it is highly volatile; loss from the tank is great, in the form of ammonia fumes. Sodium or potassium nitrate will promote the oxidation when used within a critical heat range. Sodium hydroxide (lye) is added, partly to raise the boiling point of the solution to that critical heat range and partly to promote the chemical cleanliness on parts, permitting uniform oxidation. Sodium nitrite is the first product of the decomposition of sodium nitrate. Oxidation is slow until some nitrite has been formed. Hence we age the bath and promote oxidation by the addition of a small amount of sodium nitrite.

For the benefit of experimenters, other oxidizing chemicals are potassium dichromate and potassium permanganate. Manganese dioxide or manganese acetate will act as a catalyst, to speed the reaction, while also serving to hold the unwanted red ferric oxide in solution. I find that the addition of a small, non-critical amount of tri-sodium phosphate will hasten the bluing, while giving a deeper color."

<img border="0" alt="[thumbsup]" title="" src="graemlins/bigok.gif" />

Great information, the only thing here I would again suggest, is the use of Brownells materials and again, call the tech section if you have questions, yes John I do know what thay will say, this fine group of very knowledgable folks will assist you in all means available too them and will even refer you too others in the business if thay can't answer your questions. What I wasn't going too say but will, last year, at the ripe old age of 56, I replaced for the first time in my life a new water pump in one of my trucks. Now if this seems small and unimportant chore too you, too me auto work of any kind was a mystery....but I asked a few question, and since beening retired, I had more time than money...dug right in and repaired it!! now too me this was a biggie, may seen small too you, but then you may think blueing a gun is black magic voodo...its not...just a matter of reaching out and trying. Now put the K date navy away, start small, and ask any gun shop for an old discarded barrel, or something thay are tossing away, too experment on.....have fun.

Thanks Viggo.

Hugh, Viggo and I thought Angiers hard to read. With those instructions for dip bluing it is no wonder you turned to chrome, err, nickle.

This forum is a great place.

Hey Heinz! Don't go pickin' on chrome, uh, I mean Nickled Guns! :D

Ed

Heinz,

Those were the instructions for RUST bluing, I ain't got the ones for "dip bluing" yet!!!

After reading some of these posts and looking at Mr. Green's wonderful work, I decided to re-finish and old 1910 that was deep blued long time ago. Since this gun was already blued (w/incorrect finish) and was relatively inexpensive, I thought that I give it another shot. Well, I am pretty happy. It is not as great as the ones finish by Mr Green, but for being my second attempt I think that it is not that bad. Okay, The Coast Guard is keeping me pretty busy therefore I will leave this stuff to the professionals.
Thanks, Tony

http://forums.lugerforum.com/lfupload/rside.jpg
http://forums.lugerforum.com/lfupload/top_copy1.jpg

Tony,

That looks pretty darn good! Is that a rust blue with a commonly available formula?

Thanks,
Chuck

I told you before Tony, don't sell yourself short, that is a beautiful job and your first if I'm correct...looks like you got a job waiting for you after the CG, and the straw is just wonderful....where ever did you learn that!

Well, thanks for the complement. This one took me about four days to do. It is rust blue and I got it from Brownells. You have to go slow with it and be very careful. As far as the straw, well there are some wonderful people out there that do not mind sharing their secrets. I appreciate them for keeping the eager, like myself, and the â??mythsâ?� alive.
Thanks, Tony