Rust Bluing Questions

[Woodtroll]

Hello, folks!

Being fairly handy, and fairly poor, but with some time on my hands, I've decided to attempt rust bluing a couple guns. I have a couple of questions, though.

First, can an aluminum tank be used for the boiling water bath? I know that you need steel to blue with salt solutions, but wasn't sure about the boiling bath? (I have a suitable aluminum tank, but would have to buy a steel one.)

Can a post-64 Winchester '94 receiver be successfully rust blued? I know that these cannot be blued in the conventional salt baths.

How should I treat the bore while in the boiling water bath, and after I take it out? If I oil it, of course, I will contaminate everything; but I sure don't want to just leave it bare and rusting throughout the process.

On a related note, I have some parts made of 4140 that I'd like to have a "case-hardened" finish on, but these cannot be done with the pack-and-heat method. Do you know where I could find someone to put the chemical "case-hardened" finish on them?

Thanks, I appreciate your help! Regan

[gunnut69]

Most coat the bore with varnish and use plugs fore and aft.. wood or rubber. I don't believe the M94 will blue with any conventional bluing system.  I don't know about the tank but don't know why it wouldn't work.

[koginam]

The aluminum tank will work for the water rinse. What type of solution are you going to use to blue with?  Their are additives that can be added to certain solutions like Brownells hot blue that allow you to do a great job to a Win. 94, they won't affect the bluing of other guns but it is best to add them to a batch of used salts they seem to work better.
the process I use for bluing is as follows.
Place a wire through the barreled action you will need about 6 inches sticking out the ends,  the wire is bent over two pieces of wood lath at each end of the tank and the action is submerged into the tanks.
Tank 1 is a degreasing solution soak time is 30 min. at 180 degrees.
The action is removed to a cold flowing  filtered water bath and brushed with a soft brush.
then the action is placed into a clean hot water bath 180 degrees for 30 min.
then the action is pulled out of the tank and tilted to remove the water from the barrel then immediately placed into the salts to blue for 30 min.
then the action is pulled from the salts and back into the cold flowing filtered water and gently brushed
then dipped into water displacing oil like WD40 for 30 min. then hung up to dry.
Their are several differant recipies for bluing salts and case harding at http://www.homegunsmith.com/cgi-bin/ib3/ikonboard.cgi you can also ask about bluing at http://thegunsmiths.com/phpBB2/ I have never tried coating or pluging barrels, and never had a problem.

[gunnut69]

The process koginam described is for a hot salt blue. In that process it will not damaged the bore to expose it to the hot salts..Brownells does sell a product to allow the bluing of post 64 M94 receivers.  A rust blueing process though is a rusting process andl the rust must be control between each application or pitting can occur.. Perhaps Angiers book would be beneficial. Have you read any of the gunsmithing tomes available? In general a rust process uses a material applied to hot metal that causes the formation of microscopic rust spots. This will be ferris oxide(red rust). The part is boiled in hot water and the ferris oxide will be converted to ferric oxide.(black rust). This stops further rusting at the point of feric oxide formation. The part is treated again and areas that have not been covered by ferric oxide produce a fine coat of ferris oxide and the process continues until there is not further bare metal left to rust. It has all been covered by ferric oxide and is now practically immune to further rusting. A hard oil or wax is used to stabilize the parts surface and the process is complete. After the Ferris Oxide has been converted any loose material is gently brushed away. This minimizes the size of the pits forming from the rusting process and produces a finer luster. There is no material to allow the bluing of M94 receivers(post 64) in a rust blue process. Of course there may be one available that I'm unfamiliar with..

[BoarHunter]

Indeed Angier's bokk explains quite in detail the rust bluing process but Brownells has quite good documentaion about it in their Kinks manual and a well done pamphlet comes with their rust blue product.

Once I had to reblue a Luger in a hot salt bath and the slide would not darken. I use this rust blue solution on it, then after the "rusting" time, put back the part in hot salt. Amazingly it worked.

You can try this blue on 4140 steel, it may work. The rust blue is a lot of work but still the one used for first class guns in Europe.

[gunnut69]

Some steels won't blue well in hot salt and can sometimes be made to blue by 'pickleing' in an acid solution. This is often the case on very hard parts. Perhaps the rusting process emulated this pickling process..