Tiny spot that will not rust?

[Boompa]

 In going through the rusting process on a barrel and parts there is a spot on the barrel, about 1/16" round, that will not rust. No matter what I do to prep the area, scrub, file, sand, that spot will not rust brown, it's as bright as when I started.  I'm puzzled. Any ideas?

[snapper]

how many coats have you tried?  do you have good humidity?

fleener

[snapper]

what part is it on?

could it be something other than steel?  Hole that has been filled?

Fleener

[Boompa]

   Humidity is good, rusting is fine elsewhere on all parts.  It's on the side flat of the barrel.

[T*O*F]

Take a Q tip and dab some muriatic acid on the spot.  It will etch it and start rusting.  Then proceed as normal.

[Boompa]

 I'll try that, thanks!

[Eric Krewson]

On my first build I had a small spot of mystery metal in the barrel that would not brown, the barrel is a Rice.

[Mark Elliott]

I have had trouble getting my metal clean enough.   I have found that scrubbing in hot water and Dawn detergent works best.   Acetone is second best.   

As to being a problem with the metal,  Is is possible that it could be a lead inclusion from the lead introduced to the steel?   I don't know if that is possible or not, but I throw it out there for a metallurgist to address.

[Joe S.]

I'd like to hear from the metalurgie folks too.I worry about barrel integrity in that area if that's the case.

[Dave R]

Send Jason Schneider a picture .

[Boompa]

    I've used acetone, alcohol, dish soap. That didn't work so I took steel wool then sandpaper. I'll get some M- acid tomorrow and give that a shot.  I think it's the metal, also a Rice barrel.

[Joey R]

Try some vinegar.

[Clark Badgett]

I am no metallurgist, but I do work with metals 6 days a week, 50 weeks a year, and I do not think that "something added to the mix not quite getting fully mixed in" theory is without merit. I do know for fact that there are many times I've worked with steels that have hard and soft patches in them. Metals have become quite advanced but there will always be some human error involved.

[Eric Krewson]

My spot is out near the muzzle on a C weight .54 barrel, lots of metal around it so I am not worried about the structural integrity.

I do agree with the metal mixing idea, I have a steel trigger guard on my fowler that must have had a ball bearing cast into one lug. I broke two drill bits trying to drill a pin hole through it and finally cut it off and soldered on a new lug of mild steel. The other two lugs drilled through just fine.

[n stephenson]

I had this conversation with a few builders that I`ve known since the 80s . We all have been noticing hard and soft spots as well as "bright" inclusions more in the last few years. I have proposed this theory which I fully realize could be totally wrong. I visit my local scrap yard almost daily I`ve found some really good things there . I believe that the scrap being melted now contains a much wider array of metals from more different objects being scrapped and the geographical regions from which the metals are sourced ie. China, Taiwan, Malasia , etc.  I believe in the 80s the  majority of reclaimed metals were of domestic manufacture. To make a long story short I think the bright spot on a barrel or trigger guard might just be a hubcap off a Hyundai or  perhaps a Toyota axle  Who Knows. Just a theory .    Nathan

[hudson]

Had a discussion with several barrel makers a few years ago. They all stated it is hard to get good steel. Some of them have gone together and ordered a hole heat, not certes how this worked. I am thinking when the bar was rolled at the mill it picked up some.

[ron w]

with a small risk of ruining the barrel, I would be tempted to take a small cold chisel and see if the spot can be chiseled out. my thinking is that it might be a flake of chromium from the roller or die that the barrel was made with. the die or roller might have been falling apart and should been changed out a bit sooner. you can always remove the plug and reseat it indexing the spot to the bottom flat and drill a new vent hole, plugging the original. just a thought,..... I have no real knowledge of the process used to make these barrel blanks.

[Clark Badgett]

This is making me wonder if I should cold blue the barrel before draw filing instead of using Dykem.