0m3nc0w wrote:Nope, just need to slowly heat to the temperature for the specific powder and slowly cool. Changing the metallurgy only occurs with rapid changes. . .
Hmm, that flies in the face of my understanding. If we were talking about high carbon steel that would be true. To harden high carbon steel it is the rapid cooling (quenching) from roughly cherry red hot to, say, room temperature that locks the carbon atoms into a lattice with the iron atoms. The resultant lattice is brittle but strong.
If cooled slowly the carbon atoms will find each other and nodules of carbon will form in the steel, and the result will be soft iron which has embedded carbon nodules in it. The iron is very 'bendable', or soft if you prefer.
But that's (high) carbon steel. Other metals, such as copper, or aluminum, or brass (which is an amalgam of copper and zinc) do not act that way. The other metals such can be work hardened (such as the copper wire in house wiring) or alloyed with other metals in order to attain a harder, stronger, metal.
Please pardon me if I sound preachy. That's not my intention.
The core question here is whether a snowflake wheel will be softened in the powder coating process. I simply don't know. Until I did know I would be loathe to subject a snowflake wheel to the higher temperatures associated with powder coating. I would be particularly concerned about the fit of the bearing races into the wheel.
Aside from all of that, carbon steel can be fun to 'play' with. Hacksaw blades come in many flavors (alloys), but the cheaper ones are likely to be a more simple high carbon steel. Take a worn out hacksaw blade, heat it to a glowing red with a propane or acetylene torch, and then quench it quickly in water. Then, holding the hacksaw blade in a pair of vice grips smack the quenched end against a vise and see the end of the blade shatter. Like glass!
I have a set of (some brand name) dividers that wouldn't make layout (scratch) marks on steel. They were wonderful name brand dividers, acquired at some flea market, but not terribly useful to me. With little to loose I decided to heat and quench the divider tips. That was easy enough to do with a propane torch and a glass of water. I did no tempering of the points, choosing to leave them as hard as they could be. I was, of course, risking dropping the dividers onto some concrete and breaking a tip. Using a fine grit grinding wheel and finishing with some diamond whetstones I created some nice sharp points. And I was very gratified to see the points of the dividers generate some nice scratch marks on a bit of mild steel.
Another fun with metals thing I did was to salvage some old copper house wiring. The wire was quit stiff, the natural result of work hardening as the copper wire is drawn thorough successively smaller dies. I decided that I could use some soft copper wire so I decided to anneal it. I stripped off the insulation (not all that easy) and heated the wire to a glowing red hot and then let it cool. I now had an ugly blackened piece of copper wire with all kinds of bends in it. I clamped one end of the wire into a bench vice and grabbed the other end with a pair of vice grips. I then 'snapped' the wire by bringing my arm down quickly, giving the wire a big yank. The result was a nice straight length of ugly blackened copper wire. A bit of steel wool scrubbed enough of the black away to suite me. So I now have some nice straight copper house wire which I may some day find a use for.
And that's all I have to say about that.'
Ken