TheSamba.com :: View topic - Painting body with POR-15, then primer, then paint?

Thu Mar 18, 2010 4:44 am

Ya you could epoxy it now. Just grab a red scotchbrite and rub everything you can get to with it to knock off anything it may have gotten on it. If you have a da, you could put some 180 grit or so on it and go over the whole car too.... either way. But I would do any obvious bodywork before any primer goes on at all. Filler has to be applied to bare steel. I would get epoxy on it asap.

Fri Mar 19, 2010 10:59 pm

You could cover the entire thing in Masterseries. Every bit of my suspension was done with masterseries silver and then their chassis paint. I will be using the silver on the entire body to ensure it stays rust free...I am a big fan of this stuff.

masterseriesct.com

Sat Mar 20, 2010 7:31 am

I just finished using Msterseries on my pan and some other parts. Came out GREAT!!!! Easy to use and a wonderful product.

Sun Mar 21, 2010 10:45 pm

Krmnnghia wrote: You could cover the entire thing in Masterseries. Every bit of my suspension was done with masterseries silver and then their chassis paint. I will be using the silver on the entire body to ensure it stays rust free...I am a big fan of this stuff.

masterseriesct.com

I've been kicking around doing the body of my DC this way for a couple of years, because, God knows if and when I'll ever get to afford a pro paint job, but I want to be able to drive it in all kinds of weather, and not have it slowly rust away on me.
Post pics of the body once you get started.

Mon Mar 22, 2010 5:26 am

Another thing to worry about is rock chips exposing the POR 15. It's not UV friendly.

Mon Mar 22, 2010 7:32 pm

So would it affect paint adhesion if i painted problem areas with POR-15 (heater channels, fender wells, interior body metal) and then sprayed with an etching primer, then covered with epoxy primer?

Tue Mar 23, 2010 1:12 am

19-VW-74 wrote: So would it affect paint adhesion if i painted problem areas with POR-15 (heater channels, fender wells, interior body metal) and then sprayed with an etching primer, then covered with epoxy primer?

I started with por-15(great product) and have "graduated" to Masterseries.
Give Chuck a call/email and he can fill you in on the steps it takes to do what you are wanting to do. Great product and you are supporting a vw enthusiast.

http://www.masterseriesct.com/

Tue Mar 23, 2010 7:33 am

Jason C wrote: Another thing to worry about is rock chips exposing the POR 15. It's not UV friendly.

I believe it still works fine when exposed to UV light, it just will fade that's all.

Tue Mar 23, 2010 9:02 am

POR-15 makes a primer that you can spray right over dried POR. The other option is to scuff the POR then spray whatever you would like over it.

I don't think adding etching primer over POR will help prevent rust. I believe etching primer is supposed to be applied over bare metal.

Tue Mar 23, 2010 9:18 am

Tie Coat Primer

Tue Mar 23, 2010 7:02 pm

The primer that POR-15 sells (not the tie-cote primer) is a self etching type. They claim that you can paint right over the primer with any paint. If i painted exterior areas (little bits, not the entire car) with POR-15, then POR's self etching primer, couldn't i just sand the primer and spray over the whole shell with epoxy primer and all would be well?

To those suggesting Masterseries: Thanks for the info- I'll look into that. POR-15 is what I'm using at the moment because I bought it locally.

John Morris: Does the tie coat primer adhere to POR-15 without any need for scuffing or another primer?

Wed Mar 24, 2010 2:30 am

Quote: Does the tie coat primer adhere to POR-15 without any need for scuffing or another primer?

When I used the tie coat they recommended you paint over the por-15 within a certain time frame so that you would get the best adhesion. Unfortunately I don't remember what that was, check with the person you bought it from.

Wed Mar 24, 2010 4:02 am

The Tie Coat primer is designed to go right over POR-15 with no scuffing. You can paint over POR with any paint when the last coat is almost dry if I remember correctly.

The main problem with coating an entire car with a rust proofing product is that during body work you will sand through. If your body is almost perfect before you start you may be alright. The normal procedure is to treat the metal, body work, prime, block, then prime again. If you break through to bare metal you lost the protection and will have to treat that area with something. If you use an etching primer you just respray, with POR you need a treated surface before application. I have not used masterseries.

Next time I will probably use a good etching primer on body panels that need to be really nice.

Fri Mar 26, 2010 8:07 pm

Thanks for the replies everyone!
So, all in all, my best approach would be:

1) Clean the sandblasted body with a scotchbrite pad and some solvent
2) Do any needed welding of new panels/patches (i've got quite a bit to do)
3) Clean again
4) Coat with Ospho (if i choose)
5) Fill, sand, fill, sand, etc.
6) POR-15 where necessary (don't smother the thing)
7) Use a tie-coat or etching primer over the POR-15
8. Spray the entire body with a high quality epoxy primer
9) Sand, spray, sand, spray, etc.
10) Take it in for paint!
Sound good?

One more thing: I was looking over the Ospho site and some reviews for the product and nobody seems to mention if the coating is a rust preventative product, as well as being a rust remover. In other words, does Ospho protect against rust? (not just remove)

Mon Mar 29, 2010 12:42 pm

Most of your rust starts from the inside where panels meet or where moisture and dirt get trapped so appling POR15 to the outside of the panels will not stop rust problems unless you can get it in all the places dirt and moisture get trapped.

Mon Mar 29, 2010 3:03 pm

19-VW-74, I was hoping someone with more experience would chime in. But my advice would be to etch prime the car as soon as possible after sand blasting. Even touching the metal with your hands after blasting leaves moisture on the metal and causes rust.

I dont think you need to scotch brite after blasting, the process leaves a clean rough texture that should be fine.

I would:
sandblast
etch prime
use the POR where you thought necessary (use POR products to apply, metal ready, marine clean)
body work
tie coat prime over the POR
2k over the tie coat and the remainder of the car
block
prime again etc

Before you paint you need to use a cleaner on the car to prevent fish eyes etc. If someone else is going to paint they should do this step anyway.

I have no experience with ospho, hopefully someone with experience will chime in. I have heard that you need to be really cautious when using it, really good ventilation and maybe a respirator.

Good Luck!

Mon Mar 29, 2010 3:11 pm

Sdnichols, I used seam sealer and sprayed POR 15 in areas I could not reach ... more pictures in my gallery (ghia vert) and I will add more later.

Mon Mar 29, 2010 3:37 pm

I am hoping this helps prevent some rust. I also did inside the heater channels, inside the windshield frame and eveyplace else I could get the wand. The wand was a 3M undercoating one. I had to cut the tip off or the POR would not go through. The tan curly stuff hanging in the first picture is POR putty I used to fill some pin holes. I broke off the hanging pieces before painting.

Mon Mar 29, 2010 6:32 pm

POR-15 encapsulates rust so it is sealed off from air and moisture and cannot spread. The rust stays on the metal.
POR-15 has to be applied on very clean, rougened metal or it can be peeled off like tape. Corroded metal is textured so it will stick well to it. I would never spray it over areas that I could not reach if the areas could not be cleaned and roughened, as it would not stick well to it.
Do not use POR-15 on the body; all that you would be doing is adding another variable, and any rust would still be on the metal. Use compressed air to blow off the metal, clean it with wax and grease remover, then go over it with a random orbital sander, using 80 or 120 grit disc sandpaper. Blow it off, clean it with wax and grease remover (lint free cloth), then spray metal-etching primer or epoxy primer over the bare metal to protect it from moisture. Remember that if you don't spray primer filler over it within about three days (read the directions), the primer will have set up smooth and you will have to scuff it up and apply more epoxy primer over it, then your next primer less than three days later.

Mon Mar 29, 2010 7:01 pm

I agree the car must be clean. In my case I had the car sandblasted, did a lot of sanding and cleaning by hand. Then used the suggested marine clean, then metal ready and allowed several days to dry.

But, etching primer would have probably been easier/better.