Now that your components are combined- stir with a paint stirrer from time to time as it cools down. It’ll take a while to cool down, but stir it until it becomes a thick gel. If you fail to stir it during this cooling down period, it tends to separate. Once it’s fully cooled- you’re ready to start using it!
Warm your finishing oven to 350*, pack it full of the objects you wish to darken, and let it bake until they’re up to temperature. With a heavy load of steel items, our oven generally takes about 1-2 hours to get them all the way up to temperature. Once your pieces are up to temp- drop them into the paint can full of mixture, a few at a time. Make sure that the items you put in were able to fully melt down into the mixture before adding any more on top! Sometimes, you’ll pile a bunch up in there, and the bottom layer will cool down enough to sit on top or only halfway into the mix.
Once you’ve got a few in there, and they’re fully submerged, let them cool down in there for about 5 minutes- then pull them all out with a set of tongs that you don’t mind covering in goo, and place them all on piece of cardboard (Do not stack them, make sure they aren’t touching at this point). Grab a Terry Cloth towel (or Blue Shop Towel) and start rubbing them down, removing the excess wax as much as possible, being careful not to burn your hands on these pretty hot (probably still around 300F) objects. Sometimes we wear gloves for this, because honestly- its pretty easy to get burned at this stage. Depending on the temperature you started with, sometimes I like to do a second coat to get a darker finish. To do this, i’ll take these still warm pieces and put them back into the oven to again obtain a temperature of 350F. This second heating tends to oxidize the coating a bit, resulting in a darker finish. This second heating also drips flammable beeswax within the oven- so be sure to never set it above 350, and be ready for that oven to make alot of smoke! NEVER LEAVE THIS OVEN UNATTENDED, they tend to erupt in fire- especially if the door is open (Always keep the door closed!). After this second round of heating, toss them back into the mixture, let them cool for a few minutes in there, then place them back on a layer of cardboard. Once they’ve cooled down, rub them down the rest of the way with a terrycloth or blue shop towel and enjoy!
This coating will permeate the pores of the metal, bonding to the metal and forming a waxy, water resistant, “non stick” finish- much like seasoning a cast iron skillet.
The concept here is that we’re warming and opening the pores of the metal, and operating below the smoking temperature of the mixture so it can do it’s job.
Heating the objects to different tempering colors (for instance purples and blues) will be locked in by this process, excessive oxidation on the piece will also be exposed, particularly the Red colors- those will show. For production pieces, we soak our bottle openers in buckets of vinegar for a week or so, then rinse them, and wipe off all the oxidation. This process removes ALL the scale, but the result is a shiny object without enough oxide layer to darken. For these, we’ll usually toss them back in the forge for a quick heat cycle, obtaining a dull glow then allowing them to air cool- giving us an oxide layer without producing scale. Without this oxide layer- the results won’t be very dark.
^This is how we produce and finish pieces for retail, resulting in the best/most consistent finish possible. In classes or demonstrations on the other hand, we don’t have time to warm the piece to a specific and controlled temperature in an oven. For a “quick and dirty” method- we’ll cheat a little…
Take your “as forged” piece and wire wheel or wire brush it to remove as much scale and oxide as possible. HOWEVER, you do not want a perfectly clean/shiny piece- or it won’t have enough oxides on the surface to darken- resulting in a water resistant but silvery/shiny piece.
A quick round on the wire wheel is all we do for quick and dirty pieces.
Now we heat them in the forge, one or two at a time until JUST below glowing. Often times we’ll have a little bit of color showing on the thinner portions of items, but we want to get everything to a nice consistent heat, and it doesn’t need to be very hot at all- again, we’re shooting for about 350F.
Once they’re warm, we pull them out and rest them on a steel table to allow the temperatures to even out a little, any glowing areas to stop glowing, and then we quench in a bucket of Parks 50 quenching oil, stirring them around until “Most” of the heat is gone. We do this to remove temperature quickly before moving them to the beeswax mixture- hopefully at around a surface temperature of 350 or less. If you don’t have quenching oil, water would be fine for removing the temperature- just be sure you pull it out of the water and allow it to steam off the remaining water before tossing it into the beeswax mixture.
Once they’ve cooled in the beeswax (You want them to be able to pull out completely, without the beeswax sticking- just a thin liquid coating), pull them out and rest them on cardboard to cool down the rest of the way. Once fully cooled, rub the excess beeswax mixture off with a Terry Cloth or blue shop towel.
On blackening steel with the hot oil, Use boiled linseed oil, or any cocking oil. The problem with using used motor oil now a days whether it is car or truck is the heavy metals in it, and other contaminants that can be converted into fumes. As most will tend to over heat the metal to orange to red hot which isn't needed.
You shouldn't use synthetic oils as the polymers and other stuff in them can cause headaches and respiratory discomfort.
The biggest difference in the food grade oils, is the smoke point. With canola oil being one of the highest.
You only have to heat the steel up to around 500'/600'F and then spray, dip or brush(with a natural bristle brush, not plastic). You can repeat as needed to get the shade you need.
Also the various food type oils will give slightly different colors and shades from brown to black.
And of course for any one making BarBQue equipment or other food contact pieces. The use of a food grade oil is a must, it is also recommended for anything that a child will come in contact with as most things make it in to their mouths. Sooner than later. ;D