September 23, 2010
Finishing the Metal
By Reid Coffield
The Mauser .35 Whelen sporter is close to completion. Last month I did a bit of customizing to the Boyd's walnut stock and began applications of the Tru-Oil stock finish. While the Boyd's stock is darn nice just as it comes from the manufacturer, a project like this is ideal for incorporating specific features you find attractive or useful. In this case, I altered the shape of the receiver tang, which allowed me to modify the thickness of the wrist of the stock. I believe this'll make the stock more attractive and perhaps a little easier to hold. The point to keep in mind is that this is your project, and you can use it to express your ideas as to what makes a functional and attractive rifle. That is truly one of the great joys and benefits of gunsmithing projects like this. It's your rifle, and you can make it the way you want it!
While continuing to build up finish on the stock, the next step is to apply a finish to the metal. Many hobbyists are opting for one of the newer paint-type, bake-on finishes. There's a lot to be said for these finishes. They're fast, easy to apply, and provide exceptional rust resistance. However, on this rifle, I want a more traditional finish.
The author refinished the metal on his Mauser sporter using Belgian Blue and a homemade bluing setup assembled in his own backyard.
While a standard caustic salt hot blue like you see on most factory rifles and shotguns would be ideal, the cost of putting together a setup for most hobbyists is prohibitive. Besides, the hot caustic salts can cause severe burns if any splash on you. Then there's also the problem of storing the salts when not being used. I love the finish I can get with the salts, but it's definitely something very few hobbyists can or should utilize in their home shops.
There's an alternative that's much more user friendly. It's an accelerated rust blue using the old Herter's Belgian Blue. Belgian Blue has been around for years, and I've used it many times. However, while taking an NRA summer gunsmithing class at Trinidad Junior College in Trinidad, Colorado, I learned a new way to use it. My instructor, Charles "Chuck" Grace, a noted custom gunsmith, showed me how to get a uniform, consistent finish quickly and easily. This is the same method I used in an article that will be in the October issue of Shooting Times where I blue an old Luger parts gun.
The 6x6x48-inch tanks were heated with a simple pipe burner and an ordinary gas grill propane tank.
The first step in bluing the Mauser is simply separating out the parts to be blued. There are actually not all that many pieces, but be careful when doing this as it's a pain in the tush to find that you've missed a piece when you're putting the gun together. Yep, I've done just that.
An ordinary faucet was installed in the cold water rinse tank to control the overflow.
Once I had the Mauser parts to be blued set aside, I began preparing the metal by polishing each item. I started with 120-grit cloth-backed abrasive and worked my way up to 240 grit. By the way, I would completely polish each piece before moving on to the next part. Doing that helped me to avoid missing or jumping a polishing grit.
When polishing any flat surface, I used a scrap of wood as a backer to keep my surfaces even and level. With curved surfaces like the barrel and receiver, I used contoured rubber backers. If you don't use a backer, I'll almost guarantee that your final surface will have waves and ripples. As each piece was finished, it was coated with oil to prevent rust.
My bluing setup is really very simple and one you could build yourself. Most importantly, using Belgian Blue, there are no hot caustic salts to contend with. As I said before, this setup is really very "hobbyist friendly." The basic setup consists of three long steel tanks. Two are heated, and one is for a flowing cold water rinse. By the way, if you don't want to build your own stands, burners, and tanks, all or any of this equipment is available at very reasonable prices from Brownells in Montezuma, Iowa. While the company's primary market is the professional gunsmith, it offers this same equipment to the hobbyist as well.
A small basket made of stainless-steel screen was used to hold the small parts in the tanks.
I set up my bluing outfit one Saturday on the patio behind my home. It took only an hour or so to set it up in the morning and by that afternoon I was bluing. I initially cleaned all the parts with alcohol to remove any oil, fingerprints, and grit from polishing. Following that, the parts were cleaned in a commercial cleaner I obtained from Brownells. The cleaner was heated to about 180 degrees, and the parts were allowed to soak for about 15 minutes. Once removed from the cleaner, the parts were then rinsed in the tank filled with cold water. From there the parts were then immersed in a tank of boiling water for about 5 minutes.
When the parts were pulled from the hot water tank, I heated them with a propane torch until they were hot to the touch. At that point I applied about three coats of Belgian Blue with a damp swab. The swab was nothing more than a few pieces of cotton cloth. When applying the bluing, you don't want so much that you get runs or streaks. As soon as I had three coats on the part, I returned it to the boiling water for 5 minutes.
After 5 minutes in the boiling water, I pulled the parts from the tank, shook off the excess water, and then carded the part with a motor-mounted, fine, wire wheel. The .003 inch diameter wire on the wheel is so fine that it only removes the surface rust, leaving a base coat of rust blue. Once that was done, I heated the part again with the propane torch and applied more bluing and then back to the boiling water tank. This sequence of steps was continued until I got a nice, even, black finish on all my parts. It's really easy and not all that tim
To keep the heat from being blown away from his tanks, the author used aluminum foil for makeshift "skirts" around his tanks.
One thing I learned in doing this is that you may need a "skirt" around your tanks to hold the heat in if you have even the slightest breeze. As soon as I noticed the problem, I grabbed some aluminum foil and wrapped some around my stands. It worked like a charm, though I do think I'll make up some sheet metal heat shields for future use.
Once the parts were blued, I dried them off and then applied a generous coat of oil to prevent any rusting. They were then allowed to "cure" over night. The next day I began reassembly of the rifle. In the next — and last — installment of this series, I'll put the metal and wood components together, make any final adjustments, and head for the range.Until next time, good luck and good gunsmithing!