This topic has been discussed pretty extensively so if I'm repeating what someone else has already said I apologize. I'm going to be the devils advocate here. Powder coating is a great durable finish but it does have it drawbacks.
1) The most important one is that there is no rust protection under the coating. If absolutely all the rust isn't removed and the metal coated within hours (to prevent flash rust) the rust will continue under the coating and ruin the finish. With painting you can first apply a sacrificial undercoat w/ zinc in it that will retard any hidden rust. 2) Powdercoat is thicker than paint and covers the small details of a frame like stamp marks (i.e. the VIN number on the frame rail) This may not be a problem with most but to the "back to original" restorer it is important. Also due to this fact it is more difficult to repair when it chips or cracks and if it chips and there is rust under it your in big trouble. I have chipped powder coat off of items in the past and found rust under it, so it does happen. 3) Powdercoat is direct to the metal so if you have any imperfections or pitting from previous rust it will show. Many cars have pitting rust on the frame rail under the battery that will be quite obvious when coated. If you're painting you can fill these areas with body filled prior to painting. Again this may not be an issue to the guys who just want to protect the frame from future demise, but it's important to the show car guys. 4) POR-15 is not a cure all for poor prep work. Regardless or what you finish the frame with, the ideal, and longest lasting, finish is the one placed on rust free metal. POR-15 does not stop rust it simply retards it. Also, even though POR-15 stands for "paint over rust" it has excellent adhesion to freshly sandblasted metal. The blasting gives the metal a micro rough finish that produces great "tooth" for adhesion. POR-15 also has the rust inhibitors not found in powdercoat if unseen rust is incidentally painted over. Now with all this said, my last comment is: These frames have endured 30 plus years unpainted. During this time a large number of these years were spent on harsh road conditions. They were rarely pampered the way we pamper them today. So my guess would be that any good prep (and I stress good prep) and overcoat, be it paint or POR or powder, should last a long long time. Good luck, Trooper ----- Original Message ----- From: "Ryan Langstraat" <[EMAIL PROTECTED]> To: "The Chevelle Mailing List" <[email protected]> Sent: Wednesday, March 02, 2005 7:30 PM Subject: Re: POR-15 vs powdercoating was Re: [Chevelle-list] Motor Mounts I have to be honest, I dont know if they can get the inside of the frame or not. I know when I was looking into getting it painted that they said they would "dip" the frame in chemicals and then use a spray gun on a hose that sprayed at 90 degrees from itself. As far as powder coating the inside, I honestly don't know. Ryan
