[Phlogiston]

I have been looking and haven't found any good pictures of the processes.

There are at least two ways I have done this.

Pictured is a resistor that has the original lead (Pb) ends (metal - no paint). These are made by removing the ceramic center (white part) and replacing it with a glass (preferable) or plastic tube. There are Pyrex tubes with the proper outside diameter for most of these, BUT, their inner diameter might limit the size of the replacement (watts). A plastic tube might allow for larger inner diameter but resistance to heat is diminished.

The second, and far easier, way is to mold the whole thing and paint it. I will get a picture of the mold posted when I get over to the shop.