More POR-15 or alternatives

I've got a Miata torn down to start my Exocet build (should have the kit in a few weeks)... I need to repaint the subframes, suspension, etc, but I've just confused myself on the best way.

I thought I was going to do POR-15, but now I'm questioning... the issue in my mind is that I'm not going to start with bare metal. The plan is to wirewheel all of the components and remove the bad rust, etc, but there will still be some paint or whatever the factory coating is on the suspension. I've been reading that you don't want to apply POR-15 unless you start with bare metal... thoughts?

What are my best alternatives?

I'm thinking now that I just need to remove as must rust as I can, convert the rust with Phosphoric acid, then use a good epoxy primer and then topcoat.

One of the things I wanted from the POR was a super tough coating that will tend not to chip, etc....

thanks for any help.

John S.

Sorry for the threadjack, but what year is your donor car?

I always thought POR stood for Paint Over Rust??

I used it on the RX7 8-10 years ago. I replaced the rotten spots, cleaned up everything that looked questionable as best I could with a wire wheel, treated it with Metal Prep, and brushed it on. It's still holding up well.

I've also used Rustoleum's, rusty metal primer with success, but that was on a trailer. Finish wasn't as important as stopping the rust.

I've wire-wheeled and painted over primed surfaces before without problem. Things like my rear parcel shelf...

into

The Donor is a '94

Woody wrote: Sorry for the threadjack, but what year is your donor car?

In reply to Toyman01:

So you just scuffed up the existing paint on the parcel shelf, wire-wheeled the rusted areas and applied POR?

My main concern is that the existing coating is fairly tough, but if I clean it up and don't have any loose places, the the POR will stick well...

I would just use rustoleum or your other favorite paint

jstecz wrote: In reply to Toyman01: So you just scuffed up the existing paint on the parcel shelf, wire-wheeled the rusted areas and applied POR? My main concern is that the existing coating is fairly tough, but if I clean it up and don't have any loose places, the the POR will stick well...

The stuff I was doing was under the front end and around the sunroof. Yes, I scuffed what didn't have rust under it and coated with POR 15. I haven't seen any evidence of loose paint to date. Even the places where I had to rebuild the sunroof are holding together well.

Regular epoxy should be fine for that.

I have used POR-15 on underbody panels where there was a combination of rust, bare metal from newly-welded patches, smooth paint and chipped paint. Also on gas tanks that were a combination of paint and rust.

I haven't had any problems with it coming off. My technique is (1) wire wheel everything to knock of the loose rust, grime, and loose paint. (2) Get it really, totally degreased, and then degrease it one more time with Marine Clean - Don't let the Marine Clean dry on the surface; rinse it off by spraying water with a spray bottle to rinse off the Marine Clean. (3) Let it get bone dry and use the Metal Prep they sell according to the directions, keeping the surfaces wet for about 30 minutes; don't let it dry and rinse it off with the water spray bottle again. (4) Let it get bone, bone dry and then apply one medium-thick coat of POR-15.

I have done this both in hot, humid conditions and in drier wintertime conditions where I kept the garage heated into the 50's.

There may be an easier way. All I'm saying is, this is what I have done, and it has worked well.

On the GMC project I have been using Chassis Saver (very similar but less $) over everything by wirewheeling, degreasing, and brushing with amazing success. E36 M3 sticks to the greasy miserable garage floor, glues can lids shut, destroys brushes, and makes clothes rigid. I love it.

If I was doing bare clean metal, I would use something else, but it's perfect for this application.

I just used it for some areas. On the really smooth metal areas, it didn't stick that well. It likes a rough surface.

Also, it's pretty obnoxious to work with. Use gloves, and try not to drip everywhere. It's sticky and dries like superglue. Does NOT come off skin.

In reply to tuna55:

Chassis Saver is ridiculous. I have a friend whose Open Light rally car was hit and the skim coat of Chassis Saver on his quarter panel and rocker panel was still intact even though the bodywork underneath was dented all to hell.

Granted, his application method is "wash the car, scuff it gently with a Scotchbrite pad and then keep applying Chassis Saver until it doesn't fall off." At least five layers of it but I can't argue with the results.

Tell me more about this chassis saver, like where to buy it?

I have purchased it online from Newegg (strange) and Tooltopia (less strange).

The Metal Prep sold by POR-15 is phosphoric acid, which you can get at Home Depot if you want to save some cash. Plus your lawn loves it.

Scotchbrite, take off the loose rust and have it with the POR-15. Use disposable chip brushes and wear disposable gloves. The stuff's tough, I did the frames of my Locost and the Land Rover in it. I'd do it again.

Exactly my experience! That stuff is not pretty, but works well.

Joey

tuna55 wrote: On the GMC project I have been using Chassis Saver (very similar but less $) over everything by wirewheeling, degreasing, and brushing with amazing success. E36 M3 sticks to the greasy miserable garage floor, glues can lids shut, destroys brushes, and makes clothes rigid. I love it. If I was doing bare clean metal, I would use something else, but it's perfect for this application.

I believe the local carquest has it.

Joey

WonkoTheSane wrote: Tell me more about this chassis saver, like where to buy it?

What ever you do, use gloves.

If you do get POR-15 on skin, the best way to remove it, lots of hand lotion and time. For complete removal, plan on 3 days.

Don't matter how careful I am, I get some on skin every time I use it!!

TED_fiestaHP wrote: What ever you do, use gloves. If you do get POR-15 on skin, the best way to remove it, lots of hand lotion and time. For complete removal, plan on 3 days. Don't matter how careful I am, I get some on skin every time I use it!!

Hootus.

There, I said it.

erohslc wrote: There, I said it.

Someone probably had to.

I have had bad luck with por15 the rust came back... But i am in the rust belt too.

I have been mostly coating everything with cheap rustoleum paint. The stuff from walmert that costs $20 a gallon or the cheapest gallon of bedliner. My thought is if it rusts back through at least it was cheap to buy recoat, clean up.