[tpl77]

I've blued about 15 guns now and have an occasional problem come up. I get some brownish/ red stains in random places after 4 or 5 applications sometimes. Nothing major, but as I finish more coats, the random spots do not turn to a black, nor a gray, they just stay brownish red. They eventually turn and look o.k., but if the light hits the steel just right, you can see it. It's just a blemish, but you can see it if you look close.

It's rust of some sort that doesn't turn when I boil the part. I'm using Pilkington's slow rust solution, and I'm boiling in well water. I'm NOT changing the water between coats, I'll keep the same water in the tank for 5 or 6 coats...usually until the gun is done. Is my water getting contaminated?

I'm doing a Browning BPS right now and the receiver turned up with a couple areas that are "stuck" on brown, but the rest of the receiver is coming along fine.

Any thoughts? Thanks.

[GeorgeR]

I too am using Pilkington's and have used it for a number of years. Great stuff. Also, I don't change my water between boils, like you.
My guess is that it's not your well water, its in the cleaning. I rub the heck out of it with acetone, then boil for 20 minutes in a commercial cleaner like Oakite, then boil in water that is separate from my rust blue water. I've had the same problem you're having and found that it was my lack of cleaning every time.

[chris allen]

clean,clean and then clean again.

Rust blue ---- it is imperative the steel be absolutely clean.Oil etc loves to hide under ribs ,screw holes etc and come out and bite you on the _ _ _ just when you want to blue.

Chris

[koginam]

As Chris Allen said clean is important, I use a water filter made for RV's and sold by sears, it hooks up to a garden hose and removes most contaminates. clean flowing water is very important in the cleaning tank and in the rinse tank.

[tpl77]

...I cleaned it to what I thought was spotless, but with everyone's input stressing the level of clean, I'm going to focus on cleaning the next project.

It makes sense, too. The bad spots eventually turn, but never blend in completely. I'll guess because the first 4 or 5 applications had no effect on the "contaminated" spots. After 4 or 5 applications and boil offs, the contaminated spots are clean and the process begins, but now that spot is 4 or 5 applications behind the rest of the gun.

Thank you all for the advice. I think I'm back on track.