Cold Bluing questions

[oxide80]

I've havent posted in a long time, but still pop in from time to time. Question is over Cold Bluing,,, Particularly Casey Birchwood Perma... I am building a Traditions Derhunter, Its been a fun project and was at my final step.... blue the barrel... I choose to try my hand at Cold Blue, over having it hot blued, and picked up some from Cabelas.

First 7 coats went on nicely with a light buff from 0000 steel wool in between, I thought 1 more coat couldn't hurt, It was pretty evenly covered with no streaking or light spots... Coat 8 well... it started to bead like water on a freshly waxed car...and streaked all over. Buffing lead to light spots and almost a case coloring to other spots.

Is there something I did? or just the nature of this product? I know cold bluing doesn't produce the quality of hot bluing, but I wasn't expected this seeming I had it 95% where I wanted it until it all went to hell. I will strip it this winter and try again, just would like to know if there is anything that works better or I should do different

 

[boom boom]

I've havent posted in a long time, but still pop in from time to time. Question is over Cold Bluing,,, Particularly Casey Birchwood Perma... I am building a Traditions Derhunter, Its been a fun project and was at my final step.... blue the barrel... I choose to try my hand at Cold Blue, over having it hot blued, and picked up some from Cabelas.

First 7 coats went on nicely with a light buff from 0000 steel wool in between, I thought 1 more coat couldn't hurt, It was pretty evenly covered with no streaking or light spots... Coat 8 well... it started to bead like water on a freshly waxed car...and streaked all over. Buffing lead to light spots and almost a case coloring to other spots.

Is there something I did? or just the nature of this product? I know cold bluing doesn't produce the quality of hot bluing, but I wasn't expected this seeming I had it 95% where I wanted it until it all went to hell. I will strip it this winter and try again, just would like to know if there is anything that works better or I should do different

Not a blackpowder guy but saw the chainfire posting and came in.

Cold blue is really a stain on the steel and not a chemical change involving oxidation. At a certain point, depending on the coarseness of the steel grain, the amount of buffing, etc. the steel loses its ability to take more stain-there is nowhere for it to adhere and thus you get streaking where it adhered in some places but not others. They are really not designed for whole firearm coverage but were originally developed to smooth out damaged areas of bluing. They tend do better on a matte or even rougher finish as far as darker colors as the ridges and grooves absorb more stain. The finer the finish on polishing, you are eliminating where the stain can "stick" and then as you noticed, your job regressed. One thing that cold bluing does not like is silicone contamination as the silicone can cause the beading that you observed as well as the well being full so to speak. Silicone is often found in cleaning products such as gun wipes etc.

Hot caustic bluing involves nasty chemicals and a learning curve and some expensive tools if you buy them. One thing that is easier for the home smith to do quite well is traditional rust bluing or browning which involves simpler ingredients but at the cost of time and much more physical exertion. The advantage to rust bluing is that it is an iterative process and you can stop when you want when the color is dark enough. Different formulas also give you a range of potential colors more so than caustic bluing.

 

[4v50 Gary]

I hate cold bluing. I'd go with Express Bluing. Much more durable than hot salt bluing (you still need a hot dip tank).

 

[edwardware]

First 7 coats went on nicely. . . Coat 8 . . . started to bead like water on a freshly waxed car.

Is there something I did? or just the nature of this product?

Based on your description, I think you probably didn't get the surface clean and degreased as well the last time. You're staining the surface, so a bit of oil (you know steel wool is oiled to prevent rusting right?) will interrupt that. Clean it well, and go again; I'll bet it evens out nicely.

 

[boom boom]

Any sort of contamination, oil, silicone from certain gun wipes or cross contamination, etc. can affect it The oils on your skin can affect it if you touch the piece. Edwardware above is correct that oil can affect cold bluing and cause what you see. Any product that contains PTFE (teflon) which includes certain gun oils and cleaning supplies will cause beading and stain streaking as well. Some cold blues do a bit better than others with contamination while some require cleaning with acetone before application. I usually use high grade isopropyl alcohol in between cleaner before application as it is somewhat less toxic than acetone but Oxpho blue does not seem as sensitive to contamination like skin oil

However, on stains, just like wood, at a certain point, the steel simply will not absorb any more and then you get the uneven streaking which reflects different levels of the etching on the steel due to polishing. To get really deep stains on wood, often you have to use a wood conditioner so that all of the additional stain simply rides on the surface which doesn't wear well without a topcoat. There is no similar product for steel that I am aware of. Sometimes you can even it out with heating the metal somewhat which depends on the coarseness of the steel grains, but high polish acts at cross purposes with the application of cold blue (or even to some extent rust blue), You want the high polish look, you either have a thinner layer of cold blue which doesn't look quite right as the steel cannot bond with additional stain needed to darken the color to what you want and or you have a rougher surface but deeper color.

O/P, not a blackpowder shooter but familiar with them, one thing to consider about using cold bluing is that it provides little to no protection against corrosion and may will not wear that well with the blackpowder cleaning regimen necessary to prevent corrosion. Others can probably speak more to their experiences. I have used cold bluing on individual parts or to blend a mottled finish on an old firearm until I can take more steps to restore--I usually use Oxpho Blue the most simply because the gel generally gives me better results if I am touching up a barrel or the like. Dicropan gives a darker black but is not as durable. Birchwood Causey makes some good products but I am not a fan of their cold blue. However, my stuff generally does not have a high polish finish as they are milsurps so things like barrel rings etc are usually pretty rough in finish. Brownells website (and their catalog) give good descriptions of the different bluing techniques including cold blue products--the Brownells' website also has user reviews plus Q/A with their staff gunsmiths that can indicate tweaks to whatever you use to improve your techniques. Good place to get a sense of what is available. You can call them also and get some questions answered by the gunsmiths as a customer if you wish.

I once used cold bluing to touch up a spot on a old Browning Auto 5 Belgian barrel which had a high polish and it did not turn out well regardless of how many attempts including stripping it and trying again. Tried the Birchwood first years ago on it, did not like it, tried Oxpho Blue, did not like it. The spot is about a nickel in size but each attempt to get beyond a certain point resulting in what you are describing. I simply could not get the colors to match.

Also had a problem on a Krag magazine sideplate that simply would not take the cold bluing and gave the swirling colors similar to case hardening, it was also polished. I also suspect that the case hardening on that part made that steel pretty hard--RC 45-50 using my grizzly file set to estimate hardness which left less room for the stain (very hard steel is fine grained). In that case as it was a sporter restoration, I simply left it as is as a bit of bling. I suspect some sort of staining mix is how a lot of the new/old 1800's firearm replicas recreate the colors of case hardening but that is speculation on my part.

One thing, that I am going to try when I get around to it on an old shot out Krag barrel is using Duracoat's paint that supposedly resembles bluing. Trying stuff on scrap parts is often how you can find out what works and doesn't which is why I enjoy the process. Good luck with your problem.

 

[Smokin'Joe]

Interesting video here. Combines rust bluing and cold bluing.