Twelve years ago I had Douglas barrel company send me a couple crome-moly octagon barrels to use for the following exercise. I cut these into 3" test "blocks" and stamped each with an ID number. All these test blocks were surface ground and then hand polished to a 400 grit finish. I then sent these blocks to dozens of comerical bluing companies and custom gunsmiths that marketed or solicited their bluing solution and or services to the trade. I rust blued four of these blocks with the "BEST" solutions I had found in Angiers Book (one being my favorite and one I still use today when required). These blocks were then subjected to a simple abrasion test where by each block was placed in a Ultra Vibe #18 vibratory tumbler with water and Gesswein pyramid plastic bonded aluminum oxide tumbling media (Cat # 852-1012) for 15 minutes measured to the second with a stop watch. After tumbling each block was washed off with hot water, dried and lightly oiled. Then in direct sunlight, under incandesant and Halogen light these blocks were compaired to one another and the longevity or lack there of the surface finish (IE bluing) was carefully recorded. The octagon blocks were chosen to duplicate the typical edges found on any firearm. The results were interesting to say the least. The best six candidates were then re-suface ground, re-hand polished and re-blued with the same bluing technique and solution. The blocks were tumbled again with identical results. Being pig headed the complete test was replicated a third time. The result of this exercise left me with no doubt that rust bluing did not in fact have any durability or longevity advantage over a couple of caustic salt emersion blues, quite the contrary. Sorry guys, forget what your mom told you, it ain't true!

I did this test to answer a large number of questions I had always had about both processes and not being emotionally jaded by nostalgia proceeded with an open mind hoping to eventually build a better mouth trap. I have applied both rust and caustic blue to my rifles and shotguns for what will be 25 years this June and feel I have a fairly good handle on what metal finish wears and what doesn't. My proving ground has not been the dimly lit gun parlor rather sand, dirt, sunlight, rain, wind and sweat.

I look at the application of any bluing solution as a elementary science rather than a hallowed black art. There is a place for both rust and caustic blue each has some advantage over the other in regards to ease of application for the small shop, engraving, gold inlays, soldered on parts etc. If you don't believe these results, find fault in the application of the abrasive and don't consider my observations valid then by all means please get off your tails and put your own theories to work and come up with your own data to counter mine, I'd love to learn some more on the subject.

Where does it end? how does Teflon, Black T, and baked on epoxy coatings compare? Even I've got to draw the line somewhere!

One of the added benefits of hunting Africa is that I don't have to worry about rust. Maybe bluing wear. I just wish I could hunt enough to have bluing wear!

Good post D'Arcy.

I don't have 25 years in the gun business. I got started in '82. I have made a few observations in this regard, but haven't done the testing that you have done. From the sound of it I believe that your tests and testing proceedure is pretty valid.

However, I have found there is a great range of wearability of blueing to both forms (rust and hot blue). The best hot blues I have run into are the factory Winchester and Remington circa 1950-60's. They were using a two step blue totaling about 50 minutes immersion. I think both companies were using Dulite salts. I'm sure that many gunsmiths can and do replicate this process, but many simply immerse the parts until they are blue. This blue can almost be rubbed off with your thumb.

The best rust blues I have run into are the finest grain with a built up finish. If the blue has too coarse of a matte the tops of the matting wears quickly. If it has a fine matte, it wears very well.

I have taken metal under a microscope at 40 power and made cuts through the blue. The hot blue barely has any thickness to it, while the rust blue has a 3 or 4 thousandths (guesstimate) build up.

To me, it stands to reason that the rust blue should hold up to wear better than the caustic blue. But, like I said, I haven't done any testing and it's possible the reverse is true. It's possible that the rust blue build up is softer than the hot blue.

I should point out that I have a rust blue service, so my position could be colored. I should also point out, however, that I normally recommend that rifles that are engraved with animals or game scenes should be hot blued as even the finest grained rust blue has a negative effect on the engravings.

Just my own thoughts on the matter.

D'Arcy,

That is an interesting and illuminating report!

Taking the time to actually test a cross section of the available rust & caustic bluing methods side by side certainly calls the issue out into the light. The "which method is better" arguments that I have read do not have any sort of unbiased testing to back them up. I don't have a horse in this race other than to say as a consumer I like to have as much information as possible when trying to make decisions regarding the best direction to take for my rifle projects.

Thanks for posting this info.

Regards,
Dave

D'Arcy, I don't buy it at all. I can do a very simple test with just wet and dry sand paper. It will take the caustic off the metal instantly. You have to work to remove rust bluing. And then try any acid. It removes caustic instanly, not so with rust bluing.



Sorry D'Arcy, common sense and experience tells me something completely different.

I got all you guy's beat. The perfect solution I use is "stove black paint" Holds up great on a heated barrel, cheap, and touch ups are just a finger tip away.

Now to be somewhat serious, what type of bluing was done on the old FN Browning's? I have owned several and they seemed to be some of the best to me.

Chic
To think that all that time and effort being dashed on the rocks with simple wet and dry and acid.Who would have guessed? I reckon I'd better burn the data. Jimmy I'm with you!

Chic I have a question for you. How long does it take you to wipe the sand out of your eyes before you address your blue screen each day?

I have always considered the primary purpose of bluing to be corrosion protection. If the bluing wears off it can not offer any protection, but if the bluing doesn't provide protection from corrosion then it isn't of much use (other than aesthetics) either. To this end, how does military parkerizing stand up when compared to caustic or rust blues?
Also, didn't someone used to do a black hard chrome finish, which would appear to offer the best of both?
Just some thoughts.
C.G.B.
Note, to show off engraving I prefer a French grey surface or a color case. Both of these seem to be quite fragile.

CGB, I have had several hand guns hard chromed by CHECKMATE both in Black and chrome matte finish. It is tough as hell, they do offer a matte finish in both colors. There are a couple of other outfits doing this finsh but at the moment I can't remember them.

D'Arcy, that was an excellent post, but as you can see, your analysis won't exactly make everyone happy! As one of my old friends and mentors always reminded me, "a man convinced against his will is of the same opinion still........"

My own experience with rust bluing is about the same as my experience with oil-type stock finishes: They're pretty, they're "traditional", and they look great in the drawing room, but the trouble is, they don't wear worth a damn in the field.

AD

D'Arcy, hate to blow you out of the water with common sense but whatever floats your boat, or sinks it in this case. And you can do a lot better than the blue screen crap.

Jimmy, I thought you used black felt tipped markers to blue your guns.... Makes for easy touch up in the field.

D'Arcy,

Another interesting post and more useful information available nowhere else.

I certainly won't question your results, but I would like to know more about your conclusions. If all the data is to cumbersome to include, maybe your top three performers in both caustic and rust categories.

This is valuable information, and I would be grateful if you chose to share it.

GSP7, yup always pack a brand new Sharpie for touch up in the outdoors. Really, i spose I will get laughed out of camp here in a couple of weeks. Planning a varmit shoot with a couple of senior members here and my newest walk around gun is an old rusty ,beat-up, uncaredfor 10/22 that I had bead blasted and then gave it "a new life" and an awesome camo job with 3 cans of 99 cent flat paint, scope and all, couldn't get the damn paint to stick to the sling I would post a picture but if might affect my creditability

What I would like to see are the results of a "longevity test". Throw a sample of each in a gunsafe and check them after 60 years or so. I've taken pre-war Model 70 barreled actions out of their stocks, and the bottom of the barrels were as smooth and pristine as presumably the day they were assembled. On the other hand, I have disassembled NIB Remington 700's on which contact with the barrel channel had rubbed spots on the barrels to "white metal". Go figure.

Interesting,



Mr. Echols, how many different types of "rust" blueing were tested and were there at least some rust blues that proved superior to some hot caustic?



Also would you be interested in comparing some samplings of some different types of applications to your findings? One in particular has got me very curious and I would be happy to send you a little something to "throw in the pot".

While I don't have an extensive amount of experience with rust blueing, I've probably done far more caustic blueing than all members on this board put together. I've used for the majority of that time Dulite salts, as they were required for us to meet USRAC's finish requirements.
The process that we use is a little different than the semi-automated systems that Winchester and Remington use. Since the majority of our parts are non-heat treated, they'll all blue very nicely at 280-285deg, where is the receiver, bolt,and other items that are heat treated, may require temperatures of 290 plus degrees, some up as high as 298.
Winchester's blueing is a two stage process in the salts, where it will begin at about 275-280deg.. It'll be there for about 5-10 minutes, then it will be moved to a second tank that is around 290 plus degrees for an additional 10-15 minutes.
When we blue barreled actions, the parts go in at the low temperature, and stay there until the salts are hot enough to complete the blueing procedure on all the parts. This causes a durable buildup on the softer material, as well as the hardened components.
I lived near the Northwestern coastline for the majority of my life, and hunted Roosevelt Elk, black bear, and Columbia Black Tail Deer in that area under some of the wettest conditions that you could imagine. During this time, I've had more than ample opportunities to test how well a caustic blued rifle will hold up in bad weather and wear conditions, and I've never been dissapointed yet.
With just a little common sense maintenence, a hot blue on your rifle will last many many years, without problems.
I've seen some bad hot blue jobs before, but with what's available out there today, there's really no excuse for seeing blueing wearing off under a stock.
We use blueing quite frequently for our fixture components, to prevent them from rusting and seizing up, and the blueing goes through a lot more than I could fathom it encountering in any hunt I'd want to be on, and it still keeps ticking.

Matt, I've tried just about all the newer, non-traditional finishes out in the bush, such as black Teflon, electroless nickle, NP3, hard chrome, etc. Most of these finishes come with their own set of problems, including chipping, flaking, peeling, etc., plus a loud appearance in some cases.

At this point, I've come full circle, back to caustic blueing as the most practical and durable finish for all-around use. All things considered, I doubt I'll go with anything else in the future.

AD

The best wearing blue I have ever seen is on the old Brno M21 and 22s, I assumed they were rust blue as they are very old and beatiful guns, then Jack Belk informed me that they were caustic blued guns..If that is a fact then that gives me some food for thought as to d'Arcys findings...

I know D'Arcy to be one of the finest gunsmiths around and no one would argue that point I wouldn't think, and I for one would hesitate to take him on in an arguement where guns are concerned, as I know he really goes to great pains and studies these things in detail..while the majority just accept something by word of mouth...I wonder how many have actually done any real testing on blue wear..

Not I!

If a client orders a Classic Grade rifle from D'Arcy with a French walnut stock, I'm reasonably sure that he'll still provide a rust blue finish at the client's request. He learned the art of rust blue from Jerry Fisher many years ago, and has been applying rust blue and caustic blue finishes for over twenty-five years.



AD

Just musing, but I wonder if the rust blue was superior on the steels used on older guns? The alloys used in current barrels and actions is a bit different that products made 100 years ago.

Good post. Now that I have regained my composure I would like to inquire about which caustic blue held up the best and which rust blue held up the best. Which is your favorite from Angiers?

I have used Plinktons, Neidner, Mark Lee, Plum Brown rust blues- even salt and I have noticed considerable differences in the wear characteristics even between the slow rust formulas. But I am in the corrosion resistance camp and not in the abrasive resistance camp. I believe that slow rust blue resists corrosion better than a caustic application. I feel a lot of blue wear is caused by handling and perspiration acids and less by abrasive material in the rifle's environment. Abrasives should remove the blue! Additionally, a good slow rust blue formula should 'stain' the steel black. How may of us have wire brushed an old rusty tool only to have it remain dark? I feel a good slow rust formula should behave similarly- it doesn't come off. Basically, I would be very disappointed if a caustic dip proved to outperform/outlast a slow rust blue...

On the other hand, a good deal of the rust blue's reputation for durability may be due to the fact that old school gunsmiths often coated a rust blued rifle with 'hard oil' as Belk calls it- an oil with a thinned varnish component- this would go a long way in adding protection.

Roy Dunlap had an interesting thought on this subject. He believed that a rust blued surface gave better wear and corrosion protection because of the micro pitting caused by the rusting process. He believed that this surface held oil better than a hot blued surface and (presumably) it was the oil that gave you the protection. It this is true, would not a satin finished hot blue surface offer this benefit?
C.G.B.

Contrary to popular belief, the matte finish, with it's porous texture, will hold moisture and promote rusting, unlike a smooth polished finish. The tiny pits that are created, leave an area that makes the collection of finger oils, water, and other contaminates very easy and sometimes hard to remove.
On a rifle that is to be blued, the high polish finish will rust least often given the same enviornmental conditions.

I know this goes against what most people believe, but this is most certainly the case. This same scenario is also seen in unblued steel as well, such as fine measuring instruments, and gage blocks and pins.

My .450 is bead blasted and blued, but rust wasn't what I was concerned about so much a reflection. I still paste waxed it in Moz.

I agree With Matt and feel the higher the polish, the extended time in the caustic bath with one hour as a standard, the dual cook temps are very important. The salt bath composition makes a BIG difference. In short Flaked (food grade) lye, sodium nitrate (some insist on Chilean origin) and sodium nitrite has been a winner. I know of 3 guys who used this basic make up and the results were always predictable. The only problem is one guy is deceased, one quit the trade and one I currently use. Duane Bolden was the one that quit and hands down did the finest looking and obtained the most durable caustic blue I have ever used and tested. The results were always the same and we worked on this for over a year. He's now a CPA as nobody wanted to pay him for his extra effort. What a loss! Halfmoon Rifle Company does all of my Legend bluing now and it's pretty damn good.

As for rust blue I have had the best results with the The Zischang Brown and Swiss Ferdreral Armory with a slight variation to it's mix.
With any rust blue made with an acid base 12 to 16 coats is a must. You can't stop when it's blue, sorry boys! As others have stated the longer the part is allowed to rust between coats the results for longevity are enhanced. I use only distilled de-ionized water period, rubber examination gloves (if you use cotton gloves like Angier your toast before you start)for applying the acid and carding the parts. I use a stainless tank and dergease with Simple Green. I replace the water every second boiling and keep the parts and gear very, very,very clean until it's time to oil the parts. Advantages with slow rust is it's simlpicity for the small shop without undue health hazards, hides welds real well looks great etc, etc. I do not like not being able to blue effectively in every pocket and crack. I do feel the modern steel can present some problems at times but have yet to run into typical "gun steel" that couldn't be effectively blued.

The surface prep and polish is as important as the blue no matter it's composition buffed, hand polished, glass beaded or wired wheeled the surface prep will dictate the final results as much as the bluing process. Go back and re-read that last sentence!!!!!!

Having said all this I'll end by saying while they both have a different final appearance and hue that both are elegant, and both have a place.I still prefer the salt bath and have no doubts at all which will hold up longer. Been there, done that.

Thank you Triggerguard and Darcy. I wish I could add another star to the rating, but it will only take 5 stars.

Really great information, and very much appreciated.

Blue

Interesting thread, certainly questions the prevailing consensus.

The most durable commercial firearm finish I have seen was on the SKB doubles imported by Ithaca back in the 70's. Does anyone know what process was used to "blacken" those barrels? I believe these barrels were advertised as being chromed, then chemically treated to match the blued receivers. Their "sliver" finished receivers flake terribly, and the blued receivers wear and fade like most, but the barrels hold that deep blue black very well. Whatever they used, those barrels have the toughest, most abrasion and rust resistant finish I have seen.

Roger

D'arcy, could you please post or PM me the contact info for Halfmoon Rifle Company?

Thanks!

406-892-4409

It's good to read that some are trying to improve things.

When my late dad and I were refinishing a lot of guns we used the Black Oxide Co. in New Britain, CT. I never did a salt spray test or abrasion test to compare that finish but it has stood up very well as compared to that on all of the other factory finishes I have on older guns.

http://www.dulite.com/

Mr Echols. Durning your tests did you include an example of Carbonia type blueing? While I find it durable enough, not to mention handsome as well, on 1911 pattern pistols I wonder how it would fair on a rifle.