Sometime ago,I read about a safe home bluing process. I can't find it again so I thought I'd ask around here.
The process was to heat the part to around 120 - 140 degrees (oven, propane torch, boiling water) (if boiling water dry real good).
Then apply a relatively safe bluing compound (don't recall what it was), let set for sometime (again I don't recall if it was several hours or days).
Anyway after this set time, you put the parts back into boiling water where they boiled for about 1/2 hour. Then carded off.
The boiling was done in stainless steel pots for smaller parts and section of aluminum spouting with caulked end caps added for barrels.
The key to boiling was to keep the parts always submersed and not touching the sides or bottoms.
Is this basicly what rust bluing is? Can the spouting trough be used? I was concerned about the reaction with aluminum.
Hopefully someone can fill in the missing/uncertain areas. Thanks!

Sounds to me like rust blueing

Yep, sounds like rust blueing. Usually have to repeat the process 4 -6 times to get a real good colored finish.

It's rust blueing. Mild steel tanks work too. the heat from boiling the part dries it. "Carding" is done with a very soft twisted wire wheel on buffing arbor. I don't know exactly what wheel is used as I didn't work in that department.
While safer than hot salt bluing... it would be a royal pain to do this once at home. It took the gentelmen that set up the rust blueing room several weeks to get the process perfect.

Does anyone know if the aluminum spouting trough will work?

Not rust bluing, but express bluing. It's about the same thing but no rust/humidity box is used.

I bought some, but haven't tried it yet.

Here is a link
Brownells

I've heard of several people using aluminum gutter with "end caps" screwed tight and high temp silicone used to seal the ends. They also use a coat hanger to hold the part in place during the boiling process.

Terry

Express blueing it is. Like the Belgian Express solution Brownells sells.

Rich

I've used a section of rain-gutter with end caps for boiling the barreled action during rust bluing. I didn't even screw the end caps on. I just grimped them on and sealed with high-temp silicon. It worked great.

I've since moved on to a tank that a friend made from 3" square steel tubing. He cut one side of the tubing out and caped the ends. I prefer it to the rain gutter because it's heavier and more stabile while sitting on the stove element.

Yep-rust bluing speeded up. One speck of oil bleeding out to the top of the boiling tank in the middle of the process will get on the steel when you take it out of the tank, and you polish down, and start over. If you do see the oil drop before you take the part out of the water, you can grab the oil off the water with a wad of paper towel, and save the day(or the week). Is lovely, tho- and the only way for most doubles.

Brownell's has a process like it as noted above. If you are scupulously clean and willing to do many passes, it can produce very pretty surfaces. I did a 1911 slide. Got a very pretty piece after abt 20 passes. Has lasted 15 years.

Going to try it for the background color on damascus. I'd love silver bright line (the chrome or nickel containing material) against royal blue. Unfortunate that molten nitre blue salts operate at too high a temperature for the heat treat of the blades I'm making. We'll see how that goes.