Craftsman Complete Portable Powder Coating System

[He Man]

There are MAJOR adhesion issues if you do not get the part metal temp up to 400 (PMT). It may look okay, but once a flake forms it will flake off easily. I pretty much always set my oven to 550 for 400 degree items.

Ill heat the item up to 400 degrees to outgas it pull it out and let it sit for about 5 minutes and hot flock it. this will help with outgassing. If you hot flock it the moment it comes out of the oven you will get orange peel since the immediate area around the item is heated up and draws moisture out.

this way you can throw it in the oven. and it will reach PMT much quicker.

[Jarvicious]

Where are you getting your powder?  The stuff I got from Caswell advised 375 and flowed very nicely.  I think I preheat the oven and let the part sit in for about 25 minutes before I killed the heat, then I let them both cool down together.  No sense in shocking both the powder and metal by taking it out early.  I agree about the pre-cook though.  Just a sand blast and a wash isn't always enough, but I never seem to remember and/or have the patience at the time to reeeeeeally do a super prep.  Like I said, I just finished the headlight bucket which tends to get a lot of abuse so we'll see how she holds up. 

[He Man]

i either get it from powder buy the pound, or colombia coatings.

Flow will happen at half the recommended temperature. So its not a good indicator of how the part will come out.

What really matters on the final result, is the powder thickness and how much time you have it in there for. If you get the temp lower than what is recommended and let the part stay for a while longer than the phase change from powder to a film will still be achieved. If you cut the time and dont reach the temp, the powder will instantly flow, but the phase change wont occur and it comes out with orange peel, bubbling, bad adhesion. etc.

With small steel parts, its not an issue. Steel takes in heat and retains it so you reach PMT easily.
Aluminum will loose heat very quickly, so 400 degree oven (assuming you can guarentee its 400 degrees) wont keep the aluminum PMT at 400 unless you leave it in there for a long while.

Steel generally wont out gas either, so i dont bother with hot flocking it.

25 minutes on the bucket, even if you shot it cold is enough time. you should have no issues.