Discussions board for the classic MG MGA.
I'm in the process of restoring an MGA coupe which has surface on the chassis. What type of prep do I need to do before using POR 15. Also, can you I put on the non rsuty part of the chassis as well?
Let me know. Thanks.
The directions that come with POR products are very complete and accurate. Follow them to the letter and you should have no problems. The key is to make sure there are no contaminants whatsoever on the surface to be painted. Even oils from your skin can ruin the bond. I've found that it sticks best to sand blasted surfaces but light surface rust holds quite well also, so long as there is no grease, oil or dirt on it. That includes the little corners and cracks, which is why I prefer to blast when possible. Metal ready also seems to work as advertised although a bit pricey for what it is. Smooth metal doesn't hold POR15 all that well from what I've seen. It prefers rough, clean metal with light surface rust.
I agree with Steve. I've used POR-15 extensively on several of my classic cars, and had good luck. Where bead blasting is not an option, I use first the POR "Marine-Clean", a water-soluble cleaner... just works incredibly well. I follow that with a liberal blast from my pressure washer, then finish with the POR "Metal-ready" followed by a final pressure washing. One of the things I like best about POR-15 is the fact that you can brush it on and it will dry with virtually no brush marks.
If you use the semi-gloss POR-15, it seems to have variations in the sheen (okay if using some out of sight place). However, I've found the gloss POR-15 seems to keep it's uniform texture, so I tend to use that, even on the frame underneath... probably not OEM-like look, but it sure makes the undercarriage sparkle.
PS.. for larger items, such as gas-tanks, I'll spray it on... this will require the POR solvent for thinning, otherwise the stuff is too thick for the spray gun. Just use plain lacquer thinner for cleanup, the POR solvent is mucho expensive.
Phil fm Austin
If you spray the POR 15, be sure to have good breathing protection. POR 15 contains isocyanates which can cause severe and permanant breathing problems. A supplied air respirator is best, but if you have to use a filter type respirator make sure it is new and fits well. Also, protect all your skin as it is nearly impossible to get it off your skin and is probably also harmful.
PS Even if brushing it on, you should be careful of the fumes. Have good ventilation and best to wear a mask. Can't be too careful with your health.
Man, I couldn't agree more with the requirement for breathing protection. In the past I've always used a basic filtered mask, but about 2 years ago I had a real quicky POR spray, outside, and decided a mask wasn't necessary. Damn near killed me... I was hacking around for several weeks after. Made a believer out of me. At my wife's insistence (Oh, please don't through me in that briar patch!), I sprung for a supplied air system, wish I'd done it years ago.. best investment I ever made. More details from a previous posting on this subject:
MGA Forum - Supplied Air Systems
