doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com DIY Rust Blue Humidity Box

Last summer I needed no help in the garage in N. Carolina. Come fall and winter, I had to use the cabinet. To keep it from getting to extreme in there, I've placed a heating pad from the pharmacy on the floor of the locker, with a 9"x9" non-stick cake pan on top of it. Not to fast, not too aggressive, but a good healthy rusting nonetheless.

You could also get a small crock pot at Goodwill.

If I use Laural Mt Forge bluing/browning formula, I dilute it by at least 1/2. I dilute almost everything when it comes to bluing

Great idea! I like that plan better than what I'm using. Thanks.

I am lazier than that. I bought a plastic box that is used to store long rolls of Christmas wrapping paper, just a few bucks. It works great in the winter when our humidity is low here in Missouri. I definitely don't need it in the summer.
Phil

Plywood box, light bulb on a rheostat, two wet wrung out hand towels in the box.
Try for 90�F and 90% RH. Sort of like East Texas, but works in dry Colorado.
Chuck

Sounds like the box I made nearly 40 years ago as an experiment. I'm still using it. The full length door hinge is and old leather belt, complete with four buckle hole for venting.
Mine has a build in shelf with a small rubber water dish just under the light bulb. No steel anywhere to rust or scratch.
Tall enough inside to rust a 42" M/L barrel. I try for 80% and 80*. Wet paper towel scraps for extra humidity. Two hours rusting time.
We will be using it in July for my Metal Prep & Rust Bluing Seminar.

It's interesting to see that others have issues with changes in the weather from season to season too.
I'm hoping to be able to plan my day around the rusting rather than hanging around waiting for boil time. I'm expecting some small variation in time but if a pair of barrels can go into the cabinet and I know it'll take X number of hours to get somewhere near, that'll mean I could go and do something else in the meantime without risking coming back to pitted metal. It's not a problem most of the time, but if I'm busy with other work or call outs to jobs it can get a bit tricky.

All my rusting is scheduled by the clock and all other work in the shop revolves around rusting when I'm rust bluing.
Knowing the solution, damp box and preparation rusting cycle are very predictable and vary little in timing, mainly with the first cycle taking a bit longer.
Visual inspection and experience are the last word for each cycle.
Learning to professionally rust blue require quite a bit of experience that is what I teach, my decades of experience.

BTW I'd never use a crock pot, I just don't need that much humidity. Too much humidity is more dangerous and potentially damaging than not enough.