When we powdercoat, we preheat the oven (and part if it's thick) to 450. Coat the part and put it in the 450 degree oven for 4-5 minutes (until the powder becomes glossy), and then reduce the heat to 400 and let it bake for 20 minutes. We only do small parts, So our oven is just an electric range we found on Craig's List for $50.
Hope this helps...
