A Blacksmith finish is probably a polymerization of some kind. Basically, you are leaving a burned residue on the surface. The wax and oil first penetrate the pores and crevices in the steel and the residue and oxides plug them to keep out water molecules.
Heat bluing is just an oxide color formed by heating the steel. In the days before temperature-controlled ovens and readouts, tempering was done by color.
Using a beeswax and oil finish requires heating the metal to 400°F for about 20 minutes (mainly to completely dry them) and then coating it with the wax/oil compound. Once coated, it is placed back in the oven to heat for about another 30 minutes. (Some folks drop the temp to 350° for the second soak.)
You want to use an old toaster oven for this and do it outside ... it makes a fair bit of smoke. This oven will be OK for other tempering but won't be good for food ever again
As with all potentially flammable treatments, having a fire blanket and extinguisher handy is the norm for safety. Fire blankets are so cheap and easy to use I don't know why more people don't know about them or have them. They run about $5 each in 4-packs (the cheaper generic ones are the same as the name brand ones as far as I can tell). They are reusable, too. The Amazon has a $49 ten pack with 10 pair of fireproof gloves. I give them to everyone for Christmas.
There are two methods of applying a blacksmith finish - oven and forge/torch
The oven method is by far the most accurate and best practice. It gives good results if the metal was properly wire brushed, cleaned, dried, and not touched with fingers or things that have oil/dirt on them until done. Pickling in Ph-down prior to the treatment is a good idea before doing any type of finish like these. It removes all scale and leaves a well cleaned surface once scrubbed with soap and hot water after the pickle. Dry it well and place immediately in the oven to finish drying. Once the second heat is done, wipe the object down with a
cotton cloth. Finishing immediately with a brass brush leaves a nice-looking surface.
The torch or forge heating method is less accurate temperature wise and usually gets the metal too hot and the wax mixture catches fire. Obviously, the long hold times don't work here. You just get it hot enough to fully coat with the melted mixture and then reheat to let the mixture carbonize (AKA-burn). This works fine for most shop tools and decorative blacksmith items, but isn't the best on a knife that needs to cut things. Just be aware that the smoke will ignite rather spectacularly sometimes. The container needs a fitted metal lid to close it off if it ignites, too.
Many of the old timers heated the object in the forge and tested with a drip of beeswax. When it was hot enough to smoke quickly, they would plunge the object in the can/tub of wax/oil mix or brush it on with a stiff brush and then stick back in the forge for a few seconds to heat the wax and catch it on fire. They let the wax/oil burn off, quickly rubbed it down with a piece of
cotton cloth, and then brushed the surface while still hot with a brass brush.
These methods leave a pretty nice finish once you get the hang of it. It does require working outside, wearing hot gloves, and the fire safety mentioned above.
Since you are new to smithing, I'll explain "pickling". Pickle is just a term for a mild acid solution that will dissolve the fire scale and some oxides that form in the heat of forging. It leaves a nice even surface for the next steps of sanding and grinding. The standard mixture is one cup of Ph-Down (sodium bisulphate) per gallon of water. Most folks make up a five-gallon drywall bucket of it and keep it covered when not in use. It will last for years of normal pickling steel. By weight, three cups equal a pound of Ph-Down. 2 pounds of Ph-Down in five gallons of water is close enough. 2 pounds runs about $5 at the hardware store or pool supply (or Amazon).
After pickling, wash well in running water, dry off, and proceed with whatever your next step for the knife or forging is.
