Browning issue

[sdilts]

I'm in the process of browning a pistol barrel with LMF brown and there is a spot that just won't brown. It's at the junction of the breech plug and barrel. I sanded and degreased the barrel as usual. After several coats it still would not brown so I sanded the whole thing down again and degreased once more. It still would not brown. Just wondering if anyone has had this happen before.

[Eric Krewson]

Did you sand finer than 220 grit?

The only thing I ever ran into was an inclusion of some mystery metal in my barrel that won't brown.

[Longknife]

You might have some oil that is wicking out of the breech joint,, use some alcohol in the seam to degrease ,,,,Ed

[E.vonAschwege]

It's a common issue to have - Your degreasing is only getting the surface, and there is still probably oil in the joint where the two faces meet, and that seeps out into the adjacent metal flat.  Back the plug out a few turns, wipe the back of the barrel and front of the plug shoulder with alcohol or mineral spirits, then tighten the plug and try again. That should solve your issue.  Hope this helps,
-Eric

[David R. Pennington]

Eric K, that looks like a small inclusion of nickel. I had an old blacksmith tell me that is how nickel got it’s name, from old Nick, the devil, because it would ocasionally show up in inclusions in the wrought iron and ruin the work.

[bptactical]

I have run into similar issues applying Cerakote or MolyResin on modern firearms. One thing I found helps considerably is pre baking components at about 300 degrees for an hour or so. It really helps leech out residual oils out of nooks and crannies.
I will soak the components in acetone for a while, allow it to dry then bake. Repeat as needed until no more weeping is evident.

[Lzymtlsmth]

Eric K, that looks like a small inclusion of nickel. I had an old blacksmith tell me that is how nickel got it’s name, from old Nick, the devil, because it would ocasionally show up in inclusions in the wrought iron and ruin the work.

I agree with David, after degreasing in the joint maybe, out on the flat that far away I doubt it.
In the past I’ve resorted to judiciaously draw filing or fine emery paper.
Good luck.

[BJH]

Definitely oil creeping out of the breech plug and tang joint. The only solution is to un breech the barrel and degrease the threads and the Breech plug. Then rebreech and drawfile the top flat and brown again. Been down this road a number of times.. BJH

[Craig Wilcox]

Remember after browning the barrel to un-breech and treat the threads with some anti-seize.  You may wish to remove the breech at some time in the future, and the anti-seize will help.  I use Permatex aviation copper, seems to do well.

Good luck with that project - browning or bluing can sometimes be a pain!

[sdilts]

I sanded with 150 grit then cleaned it with acetone a couple of times. It still won't take. I may try backing the plug out and sanding/cleaning again. The only problem is it has a patent breech and that is not the easiest thing to tighten/loosen without tearing up some metal.

Thanks for the tips.

[D. Taylor Sapergia]

I always brown/blue the plug separate from the barrel.  Otherwise, one can expect a n area ahead of the plug to be of lesser quality brown/blue than the rest of the barrel.  But I have also experienced having some mystery inclusion that no matter what, will not brown/blue the same as the rest of the barrel. 

[hudson]

I am inclined to agree with David R. looks like inclusion. Don’t think it’s seepage from the breach plug.