Evaluation of cold bluing products (w/pics)

[Ron]

If you have read any of my restoration threads you know I do a fair amount of cold bluing. I’ve gotten a few messages asking about the task and which cold blue is best. The thing is I really don’t know how to answer that since it’s hard to define best. Is it the lowest cost blue or the one that is easiest to apply or the one that color matches your gun the closest or is it the one that staves off corrosion the best or is it the one that does not wear off?? I don’t think there is one that meets all those criteria but I am willing to find out.

For most people, it might be the one that their local store carries so that’s all they have tried. At the same time there are questions from capable folks wanting to tackle their gun project but are uneasy about baring the metal and touching up or rebluing an entire gun out of fear (and the cost of a professional job) so they do nothing.

Since we learn by doing and improve by self reflection and because I too can get in a comfort zone with products I use, I decided to get a bunch of cold bluing products that are easy to find (the internet makes all of them easy to find) from local stores such as Gander Mtn and Cabelas and online from Brownells or at gun shows. All the products would be easily obtainable to somebody planning to do some bluing. I bought mostly known name brands (but not all of the brand as I don’t have unlimited time or money) to do an evaluation.

But first, a few things to get out of the way.

1. This is not a test. To call it such would be unfair to every test heretofore conducted. This is an evaluation and a comparison of several cold bluing products, nothing more, nothing less. If the cold bluing nirvana exists and it’s not part of the list of products I bought, then the best I can do is tell you about ones I am about to try.

2. I am not a pro. I am a hobbyist just like you but with some experience with metal, be It making custom knives or gun parts or gun restorations. I have a day job in the medical engineering field and metal and guns and knives are just relaxation. This evaluation is not for the experience bluer with a favorite product and special tricks to get a better blue job. This is for the novice contemplating trying bluing but confused by all the brands/claims available. This is not MY way of using blue but rather the Mfgr's instructions for using their blue.

3. I anticipate complaints and helpful comments about how I should have done this for better results. That is not the point of this evaluation. The average guy wont know special tricks and techniques to get better results and will only follow the instructions so if you have found better results by first coating the barrel in ketchup or lime-away or unicorn pee or only bluing during a full moon, that’s great info and I think folks would like to know your special tricks to achieve improved results (if you can quantify it with substance) but for the purposes of this evaluation it would be unfair to do anything but what the directions instruct.


4. I am not beholding to nor affiliated with any product or company I am about to mention. I’m just curious about cold bluing (and based on messages I have been getting, so are you.) I plan to be completely impartial since I have no reason to try to sway the results since I am hoping to find the best blue to use myself.

Enough prattle. The products I will be evaluating are (in no particular order)



Everything you want to learn about G96 can be found here.

www.g96.com/products/gun-blue-creme/#



Everything you want to learn about Oxpho-blue can be found here.

www.brownells.com/gunsmith-tools-supplies/metal-prep-coloring/metal-bluing/liquid-cold-bluing-chemicals/oxpho-blue-reg--prod1072.aspx



And this will educate you about Dicropan T4

www.brownells.com/gunsmith-tools-supplies/metal-prep-coloring/metal-bluing/liquid-cold-bluing-chemicals/dicropan-t-4--prod1085.aspx



Here is the link to Birchwood Casey Perma blue

www.midwayusa.com/product/419877/birchwood-casey-perma-blue-cold-blue-3-oz-liquid?cm_vc=ProductFinding



Birchwood Casey Super blue.

www.midwayusa.com/Product/284241/birchwood-casey-super-blue-cold-blue-3-oz-liquid



And Finally Nu-Blu from the Stock Doc. (which appears to only be available online or at gun shows. I bought mine a 2 weeks ago at a gun show from the Stock Doc booth.

stockdocusa.com/products.html

I know what you’re thinking. “Awe man he isn’t trying Brand X or brand Y and that’s what I use or can get my hands on.”

Sorry.

Ive asked my wife to assist me with this evaluation. She is always commenting on how we never spend enough time together. This will be a good bonding experience.

The sample metal sticks were all sheared from the same cold rolled steel sheet into manageable sample sizes



Then all were given a unique alpha identifier stamped into both sides that will be linked to the blue brand. You may have noticed there are more samples than there are bluing compounds. The extra samples will serve as a control since I plan to do a corrosion evaluation after bluing coupled with Birchwood Casey Barricade as well as an abrasion resistance evaluation. More on that later as I need to encourage my wife to work a little faster at the buffing wheel. You know, more work, less talk and make sure to lift with your back and that sort of positive encouragement.



A common theme in messages I have gotten is in regards to metal finish and metal prepping cleaning) and if mirror polishing is needed for a good bluing job. It been my experience that time spent prepping the metal is never wasted and a blue does not hide defects in metal finish, it actually makes them easier to see. So to that end, each sample is polished on one side and the other side gets a 400 grit brushed finish since that is comparable to the finish on many guns and any swinging Dick can buy 400 grit sandpaper and 0000 steel wool and produce that quality of finish on an entire gun or to spot remove rust from a portion of a gun. And because when I told my wife to polish both sides of the samples I had to dig one out of the drywall just to the left of my head. I think she has a little ninja in her.

Polishing was done on a very simple flannel buffing wheel with red rouge. Anybody with a bench grinder or drill press or even a hand held drill that lives near a hardware store can (if they desire) pick up a buffing wheel and buffing compound. The question is, is the repair you are doing next to metal that has a brushed finish or a polished finish because matching the blue won’t mean a darn thing if you don’t match the metal finish. Polishing a spot while the surrounding metal is brushed won’t match just like a rough finish surrounded by polished metal won’t match and no brand of blue can correct this.

Here are the samples viewing the polished side.



And the 400 grit brushed finish side.



Here is a very brief video of one of the samples so you can wrap your head around how they look prior to bluing. (I won’t win any awards for cinematography and yes I’m wearing Crocks (deal with it)



I read a lot of comments about what to clean the metal with prior to bluing. There are all sorts of ideas and ways to do this but simple is better. All you are trying to do is apply blue to clean metal that has no dirt, grease or oil to prevent bluing action. No need to get fancy. Acetone or denatured alcohol is all you need, hell hot soapy water with a rinse will do. You don’t need acids or etching media (because the blue will etch the metal just fine all by itself). None of the makers of bluing instruct users to use vinegar or acid or any other specialty product to etch or srip or clean the metal. While I understand that people are free to take additional steps in cleaning metal if they really think it helpful but I will be sticking to mfgr intructions for a fair evaluation.

All the metal samples for this evaluation were cleaned and degreased in the same manner. Acetone was used as the final degreaser because clean metal is paramount to a good blue job. Once cleaned, do not touch the metal with bare skin unless you like to see fingerprint spots where the bluing wont take. The chems you use for bluing are caustic poisons. Wear rubber gloves to protect you and the metal. (note. Not all rubber gloves will stand up to acetone)

Follow the instructions. Each bluing product comes with instructions for the best possible results. Follow them. All the blues I am about to evaluate were used according to their instructions. All stated that it should be applied, allowed to work and then rinsed off with water to neutralize the action of the bluing agent or simply wiped off. They all stated to buff/card the area blued with fine steel wool after bluing. Some but not all stated that additional applications may be needed to achieve a desired color or color match. Trust me ALL of them will require more than one application especially if you are doing a complete reblue. I will show you how each sample looks after just one application of blue and then I will apply 3 more applications for a total of 4.

**note I have been known to apply as many as 7 applications on guns I have worked on until I got the desired results**

The process will be

clean

blue (applied with cotton)

rinse with water and dry (or wipe dry)

buff with Steel wool

repeat 4 times with the last application of bluing applied with steel wool

One deviation from this SOP was made for the Stock Doc brand bluing (Nu-Blu) which called for heating the metal before applying the blue. I heated the metal with a propane heat source each time to a temp I could handle without burning my rubber glove covered hands. Again I am keeping with the instructions from the Mfgr to make sure each is getting a fair shot. Nu-Blu was the only blue which instructed me to heat the metal, The only other blue to mention heat was G96 and as you can see from the front label it states “No heat required”. I know heat affects metal but I would think that if better results could be achieved with heat the Mfgr would instruct you to apply heat. Since Nu-Blu was the only one instructing to heat the metal, That is the only brand in which pre-heating was used.

[Ron]

Here is the lineup of blues.



The bottom of each sample was taped to prevent bluing from contacting the metal for reasons that will be explained later. Here is the lineup of samples. A thru F are the bluing samples, the other 2 are the controls and have also been polished on one side and 400 grit bruised on the other. An additional control will be added which is a sample from the same sheet of steel but it will have nothing done to it in terms of sanding or polishing or bluing.



Each sample is then blued according to the Mfgr instructions. This is the appearance after the first application of blue. The first application does the most to the steel in terms of forming the oxide and black powdery soot (for lack of a better term). The first application does the most in regards to etching the metals surface. These samples have not been steel wool polished to remove the oxide soot. Samples A and E were the most caustic to the steel while C and D made the steel the blackest. After the blue was applied I wiped the pieces down with a clean paper towel prior to rinsing with water. All the samples soiled the paper towel with black soot except F. The soot was brownish red from F.

The dried samples were then buffed with 0000 steel wool. This is their appearance after the first bluing application and buffing.



Bluing etches the metal as it forms the oxidation. This impacts the polished surface. Not all the blues were equal in the caustic etching. Samples C and F retained the polished finish the best. Its hard to tell from still photos so I shot a short video showing the samples. You can see by the reflection of the overhead lights in the metal which samples retained their polished surface and which ones etched away the smooth surface finish. This video is of the polished side of the samples



This video is of the 400 grit side.



I took notes during the bluing. This is what I noted.

The least powdery (soot) finish was created by F

The least streaking (overall uniform finish) was sample F

The darkest bluing of the metal was on samples C and D

The least coloring (bluing) was sample E

The most streaking and powdery buildup was sample E

Then all samples were blued 3 more times. Here is an image after all bluing and buffing is complete.



My notes state the following

The least overall streaking and most uniform finish were samples B and F

The least caustic (white corrosion forming while the liquid sat on the metal) were D and F

The sample that retained the most polished finish on the metal was F

The darkest sample was D followed by F

The least dark was E

I asked my wife to write down her observations but the words she used most likely would not make it past the censors. She is such a kidder.

With this first comparison complete and based on these criteria.

Darkening/bluing of the steel

Uniformity

Retained surface polish

I have to give the nod to F with C and D coming in close behind.

Bluing, coloring the steel is all well and good but how it stands up to use is just as important (unless you like to reblue over and over because it wears through) so the next step was to evaluate how well the different blues stand up to abrasion. All the blued samples were taped off with a double layer of painters tape at one end of the sample so it would not be worn away but would lay directly next to the wear area for comparisons sake. Each sample was placed in a vise and given 200 strokes with a fine bristled (but stiff) stainless steel brush. Each sample will also get 100 strokes with 000 steel wool, then the tape will be removed to compare the wear and non-wear areas to see how well they retained the blue. This abrasion exercise is far more aggressive than normal gun use and would be considered extreme abuse but I didn’t have 10 years of pulling a gun out of a cloth case to see which wears better.

Here are the samples before the abrasion exercise.



Here are the samples after the abrasion process.



And viewed from another angle.



My notes state (and the pictures show) that samples D and F retained the most bluing and sample E lost the most bluing (but then E was the least blued to begin with).

During this process and so I get an additional opinion I would show the samples to my loving and supportive bride and ask her to point out the darkest and the shiniest and the one that retained the most bluing, etc. (also because she knows nothing about guns or metal or bluing or why this would matter, she would be a good impartial observer) She doesn’t say much but when she does she gets right to the point. So when I asked for her thoughts she looked at me and said:

“(Sigh) I thought you were going to fix that dripping kitchen faucet today? You promised me you would do it this weekend and the new faucet is still sitting in the box on the kitchen table? You always get sidetracked by your gun projects and my projects always blah blah blah blah blah (eye roll) my mother warned me that you were blah blah blah.”

But anyway, I digress. For the ability to stand up to abrasion (and haughty criticism with a hint of frustration) the nod goes to D and F. The samples that gave up the most bluing were E followed by A.

[Ron]

So your bluing looks good and it wears well but how does it stand up to corrosion? That is after all the reason we blue our guns. So I did a corrosion comparison. I mixed a cup of tap water with one tsp of non-iodized table salt to act as the corrosive medium. Why that ratio??? Saline solution and our tears are equal to ½ tsp of salt to a cup of water. I was looking for something a bit more corrosive to speed things up. I need a container to hold the metal samples and the salt water. When your wife is searching the web for instructions on how to replace a leaky kitchen faucet you can steal away with a 9 x 13 baking pan unnoticed to put your metal samples in. I will return it when Im done.

Not wanting the pan to influence the evaluation (and because I don’t like getting yelled at) I laid down 2 layers of freezer paper and then a paper towel. I sprayed down the paper towel with the salt water to saturate it.



Next I sprayed barricade rust inhibitor on a paper towel and wiped only the 400 grit side of the samples and laid them on the wet paper towel because I wanted to test the corrosion resistance of Barricade since we all wipe our guns down with oil or some protective film. Nobody reblues a gun and leaves it unprotected. That being said, the polished side of the steel went without any protection to see if any of the raw blues performed better against corrosion than the other blues. The controls were protected as the image below describes.



As you can see, each blued sample, on the polished side (thanks to taping off at certain times) will have a blued area, an abraded area and an unblued area. Then the samples were covered with another sheet of paper towel and again saturated with the salt water solution.



Lastly another layer of freezer paper was used to depress the paper towel against the samples to make sure contact was made and the entire pan was then covered with plastic wrap to keep it from drying out so as to maintain a humid environment. The plan is to let the samples rest for 24 hours or until my wife notices her pan is missing.



Meanwhile, my wife is making great progress with the sink ………………..



After 24 hours of the samples sitting in a salty/humid environment, they were uncovered and examined.



Initial observations of the polished side show that F and A had the least amount of corrosion. Note that control G was not blued nor protected by Barricade and it faired the best of all. This is because a polished surface always stands up the best to corrosion. I learned that a long time ago as a custom knife maker. Highly polished knives are less apt to corrode than rough finished knives.



The samples were then wiped dry and buffed with steel wool to remove the corrosion and compromised bluing. Since still photos don’t do it justice I shot a video to show the appearance of the metal samples. You can see where the bluing was completely removed. (more reason to use a rust prevention solution on your guns)



Then I flipped the samples over to observe the 400 grit side that was blued and protected with Barricade. Despite the Barricade some samples still corroded but only slightly. Samples F and A had the least visible corrosion.



Another view



Here is a video of the 400 grit side after being steel wool buffed.



I replaced the freezer paper and paper towel in the pan with new versions and again wetted it with the same salty solution. This time I coated all blued samples (both sides) with Barricade and again laid them on the paper towel since its pretty clear what happens to unprotected metal.



And again I covered them with another paper towel that was saturated with salted solution. By now you have probably observed that the cake pan did not stand up well to this environment. I have not shown the pan to my wife yet. My wife likes her jewelry, while it may seem out of date she still wears a mood ring. When she is happy, it turns blue. When she is angry it leaves red marks on my forehead. I will delay showing her the pan for now.



The plan is to leave the samples in this humid environment for another 72 hours. This will give me some time to run to the store to buy a replacement cake pan. This kills two birds with one stone since Mother’s Day is coming up and a new cake pan wrapped up with a boxed cake mix makes a perfect gift for any mother. I won’t make the mistake of buying her a leaf rake and weed trimmer line like last year. I think she liked them although she mumbled something that sounded like “shoulder pads for a snake”

Fast forward 72 hours and this Is what the samples looked like after removing the top layer of paper towel. This is the 400 grit side with a heavy application of Barricade. Samples A and F look the least corroded.



Clearly no bluing (which etches and compromises the metals surface) performed the best while unpolished, unblued and with no barricade (Lower left sample) performed the worst based on the picture below. This suggests that if you highly polished your gun and didn’t blue it at all, it would stand up the best to corrosion (but would be shiny as all get-out)



Again, still photos make it hard for you to see what I see so here is a video of the polished side.



The final comparison was going to be cost but because none of these products will break the bank since they can be purchased in such small sizes I don’t know if price is a motivator or a reason to buy one product over another. Are you looking for the best bluing product for your firearms or are you buying based on price? The prices ranged from $8 to $13, Again, not enough to make a purchase on price point alone and since any one of these bottles of blue will last the average sportsman a lifetime of touchups, price really isn’t that much of a driving factor.

It should be noted that many of the blues cost more for shipping than the product itself and paying for shipping is not a value added expense. Having purchased Dicropan many times through the mail I can tell you that caustic and hazardous shipments can really inflate shipping costs. The last time I bought Dicropan from Brownells the product cost was $12 and the shipping was $15. Those extra $15 didn’t make the gun any bluer or protected from the environment. If you do not live in the lower 48, you may not be able to get all of these products via the mail. But since I touched on the price factor, the lowest cost for shipping via an online order was F.

With all the evaluations complete, my notes indicate that I should probably be switching my standard, go-to blue. (that was after all the reason for spending the time and money and straining my relationship with my bride on this evaluation) I want to provide myself and those I do restorations for with the best cold bluing I can get my hands on and based on color, uniformity, abrasion resistance, and corrosion resistance, I need to stock up on “F” Nu-Blu. You however are free to buy which ever blue you like. I am not trying to tell you what to do.

Lastly, as it relates to rust inhibitors, Your gun cost you plenty. You want it to look and perform well for many years. Protect the metal. Remember this. Oil is a lubricant. Its not a rust preventative. Oil is also hard on wood and gun finishes. Get a product that is labeled as a rust preventative or inhibitor and put it on the metal only. In the future I plan to secure a variety of rust inhibitors to do an evaluation much like this one.

I want to thank this pan for giving its life in the service of gun owners everywhere. Although I wonder if there might be is a cake pan restoration thread in all of this? I could strip the finish and blue the whole pan. My wife would be the envy of the church cake ladies with such a tricked out piece of cookware. Sounds like a great birthday present.



So there you have it. Not all blues are the same or created equal. Use this info as you see fit.