No, it's not heavy paint.
Just 31 gallons of it. :D
(Aproximate 8 lbs per gallon devided into 250)
Powdercoat is literally powdered plasic that attches to the base metal magnetically and is then baked (Melted) on.
You can learn a ton about it here at the Powder Coating Institute website, and then go to the Publications tab at the top right of the page.
http://www.powdercoating.org/11/Our-Industry/What-is-Powder-Coating