POR-15 use

[cstreit]

I'm thinking of doing the racecar boot in POR-15. They say not to paint it over any other paint. Is this a real issue? Stripping all that paint off ain't gonna happen... My alternative is automotive primer and paint but I'd like to avoid spraying in the shop over winter...

Have you put POR-15 over paint? Where's a good source?

[vanwyk4257]

I think the POR-15 will only bond well to bare metal with a little bit or "patina" on it. I have never used it over paint myself. I would just get some knotted stainless steel wire wheels and go to town with an angle grinder. I stripped the entire underside, front inner fenders and engine compartment on my old '72 that way in just a couple days. They will go through the paint like a hot knife through butter. I have a couple I can send you for the cost of shipping if you want to try them out.

[cstreit]

Ughh... I'm really trying to avoid stripping all the paint. It would just be a time sucker. I want to seal in the surface rust but not strip off all the paint.. Too many nooks and crannies in that boot... Even stripped of all components it's still a nightmare... I dunno man. maybe just some neutralizer on the rust spots and a good auto primer...

[jh225]

The whole idea of the POR15 is that it chemically adheres to the pores of the metal, and then catalyzes, creating a super tough product. I have used it for years on everything from frames to parts and it works as stated.

I do NOT believe it will adhere properly over painted surfaces, even if scuffed up.

[Scott R]

Originally Posted by jh225

The whole idea of the POR15 is that it chemically adheres to the pores of the metal, and then catalyzes, creating a super tough product. I have used it for years on everything from frames to parts and it works as stated.

I do NOT believe it will adhere properly over painted surfaces, even if scuffed up.

True, it creates an odd shell over the paint and eventually cracks off. Like that old ice cream product, "magic shell."

[cstreit]

Originally Posted by Scott R

True, it creates an odd shell over the paint and eventually cracks off. Like that old ice cream product, "magic shell."

Crap. Might just be easier to primer/paint it then...

[jlex]

Maybe you could just chemically strip it, then use the POR 15...

jlex.

[ossiblue]

Without pictures it's hard to tell the degree of rust in your car but you mentioned sealing the "surface rust". All you have to do is clean the areas of rust to surrounding clean metal, prep according to POR-15 directions, and paint it on up to the solid metal/paint areas. Yes, it will look patchwork, but you don't have to strip all the paint and you won't POR-15 over paint where the bond will crack. There is even a POR primer you spay over the finish that allows you to paint a finish coat of your own color.
You have to decide if this is practical. I've used POR-15 in this way in areas that are concealed and, IMO, it is superior to primer--if all the prep is done properly.

[onboost]

Por-15 will adhere to anything you put it on!

As with any paint product you need to scuff the surface and degrease.. then have at it!

[Scott R]

Originally Posted by onboost

Por-15 will adhere to anything you put it on!

As with any paint product you need to scuff the surface and degrease.. then have at it!

Takes about 10 days to get it off your hands.

[jpnovak]

Chris,

I have used it on top of undercoating and previous painted surfaces. Scuff them good and it will stick pretty well. Keeping the surface ultra-clean is the key.

I would suggest another route. go to the Marine boat store and buy some Epoxy deck paint. Mix it without the thinner(reducer) and brush it on after surface prep. It is usually white to match the car and will be incredibly durable.

[J P Stein]

I've had excellent results with Rust Mort....SEM makes it. It looks like colored water but converts rust to ...Iron Ferrite, IIRC. When it dries one can then shoot bout anything over it. I use a rattle can etch primer in tight spots...an RM product IIRC. That will accept any top coat if you feel the need.

All this stuff is available at a good Auto paint store. Ask them what they think of POR-15.

[onboost]

Originally Posted by J P Stein

I've had excellent results with Rust Mort....SEM makes it. It looks like colored water but converts rust to ...Iron Ferrite, IIRC. When it dries one can then shoot bout anything over it. I use a rattle can etch primer in tight spots...an RM product IIRC. That will accept any top coat if you feel the need.

All this stuff is available at a good Auto paint store. Ask them what they think of POR-15.

Yeah that's good stuff. Oxi-Solv works well too

Scott R: I know what you mean. I got a little on my face.. was in a hurry to finish up, thought I wiped it all off. Missed the spot on my nose..had to use a bit of lacquer thinner..and almost rubbed it raw!

[HarryD]

FWIW,

If you read the instructions for using POR-15, they tell you you need to use their "Metal Ready" product. If you look at this product, you will find out that it is similar to Rust Mort or Naval Jelly. It convert rust (iron oxide) to another iron product that is more stable.

IMHO, POR-15 is a coating that encapsulates the coverted rust. As JP points out, any good paint will do the same thing.

For that matter, I like using Permatex Rust Treatment or EXTEND in hard to reach places as it does the same thing but does not require a top coat.

[john walker's workshop]

i've had problems with using it over paint as well.

[the]

It is not designed to go over paint. You can do it, but you won't get any of it's real benefits.

Best is to read the info on their website.

[advtracing]

good info!! i was going to use por-15 on all the seams while i have my car stripped , but was told that if you don't paint over it in 48 hours it will become so hard that no paint will stick ??? is this true

[the]

Read the info on their website.

As far as painting over, what they say to do is spray a light coat of primer while the POR is stilly tacky. That will give the paint or subsequent primer coat something to bite to. I've done it and it's worked very well.

[Zeke]

Originally Posted by john walker's workshop

i've had problems with using it over paint as well.

What kind? I've used it many times over spot repairs which were bare metal surrounded by painted surfaces. I obviously overlapped the paint. No problems here that I know of.

[RoninLB]

I use the Por as thin as possible... seems to remain more flexible that way.

I've also used it overlapping other paint after scuffing it with at least 400 W&D.. gotta give it something to grab on to.

I just used Por-15 after cracking some paint under and on the outside of the well during wheel well rolling. Scraped off loose paint, 400 W&D to the area, Por-15 on bare metal etc and to fill in the open area inside the lip, then sponge brush some color metallic and thinned Imron clear under and on top blended in with the tub.

Lots of good product out there. Different strokes.......