rx-711

iTrader: (2)

help, i degreased my engine bay and scrubbed it with some scoth brite pads. yesterday i started painting it with por-15. when i started painting alot of the bigger areas like the shock towers it wouldnt stick and become blotchey. once it got tacky i tried putting some more in those spots and it and helped alittle. also it feels like there is also sand in it through out( its not form lack of cleaning) what im wondering is should i just give it some time and let it dry and try sanding it alittle and throwing on a top coat and if that will cover some of the spots. do you think the cold has anything to do with it either. thanks in advance

jerd_hambone

Whats the temp there?

Also did you get any kind of finishing coat off? Any kind of clear will cause adherence problems

rx-711

iTrader: (2)

its probably about 40-50 degrees in there. i didnt get any kind of clear coat

V8slayer

waiting on cake

mightymite

iTrader: (1)

yes the temp does have a large part in how the paint lays down. u want it to be at least 60 and u want the paint to be the same temp as what your painting is. water in the air can make paint haze or fog. btw por-15 takes a long time to dry u can thin it and it will also help spead it more even....oh and one more thing what was the last thing on the paint before u painted it most cleaners leave some kind of resedue.

classicauto

iTrader: (3)

What??

To the OP:

Blotchey-ness: Too heavy of application, poor cleaning (fish eyes?) will cause it among other things. It may also be that its sprayed well (light coats) but hasn't acheived coverage yet.

Dust/dirt nibs: Lack of cleaning, not filtering the paint, too dirty an enviroment to spray in. Doesn't matter if you think you cleaned it well enough - the dirt must either be on the panel, in the paint, or landed in it while wet to appear.

Temperature: There's MSDS and tech data sheets for every type of paint you can buy. Most paints shouldn't be applied in anything lower then 15C. Check the tech. data sheet for the product to verify.

rx-711

iTrader: (2)

i didnt spray it i brushed it on

jerd_hambone

You can not paint over clear coat, i asked if he removed any clear that was on the engine bay.

And at the temp he was painting at, the paint probably wouldn't stick.

rx-711

iTrader: (2)

what do you think is the best way to fix it. wait till it completely dries and warms up and sand it alittle and apply another coat... will it stick to itself

RETed

I thought you're not supposed to put POR-15 on painted surfaces?
I thought it was bare metal only?


-Ted

classicauto

iTrader: (3)

Says who?

Now, POR-15 itself isn't designed to stick to ANYTHING aside from rusted metal or "seasoned" metal as they call it. Its a super high performance Tremclad.

Best way to fix it (IMHO) would be to wash all of it off with thinner/gunwash and start over with somethign that you can apply to apinted surface, such as regular paint. Or wait till its dry and sand the whole thing down smooth and apply more.

EDIT: http://www.por15.com/Data%20Sheets/P...cationInfo.pdf

According to that info sheet you can apply it to smooth painted surfaces but there's a special prep involved. Instructions FTW.

ITSWILL

iTrader: (12)

i used por15 on a truck that i am restoring and i painted it on as well. i did noticed when it was colder even though my stuff was clean it would come out gritty. I bet if i had sprayed it it would have been ok though.

kustomizingkid

iTrader: (2)

POR 15 uses the moisture in the air to harden. cold dry winter air is the absolute worst situation to apply it in.

jerd_hambone

I am by no means a professional painter, but every time I have ever painted over clear the paint I sprayed had adherence problems

Maybe it was just me or the temp, but it was about 70 in the garage and any part that the clear wasn't sanded down had paint chipping off

classicauto

iTrader: (3)

There are no issues with painting over clear coat. Its done every day, hundreds of thousands of times a day, at body shops and paint shops world wide.

If you had adhesion problems, it was something entirely case related, or prep related.

Aaron Cake

iTrader: (1)

Looks like someone didn't follow the instructions....

POR-15 is designed to be painted over "seasoned" metal. It needs a tooth to grab onto. This means either rusty, or new metal that has been etched.

The basic procedure is to:

1. Degrease and CLEAN, CLEAN, CLEAN. Then clean some more, and next you clean. The surface must be free of all GREASE and OIL. Rinse several times with water.

2. If you are painting over paint (not recommended) then you need to roughen up the surface. A Scotch Bright pad isn't going to cut it. You need 80 grit sandpaper. Give it a good sanding. If you are not seeing bare metal in spots then you are not sanding enough.

3. Clean and degrease again to remove sanding debris.

4. Any time there is rust or new metal visible, the surface must be etched. Grab your spray bottle full of MetalReady, apply liberally and wait 20 minute. Rinse off. This is a KEY step if you have clean metal since the MetalReady will etch the surface and allow the POR-15 to stick.

5. Allow the surface to dry. This means BONE DRY.

6. Apply your POR-15. Follow the instructions. You can lay it on thickly. Work from a small cup or can of the stuff, not the big can. Keep the can sealed while you are painting.

7. After about 2 hours, you can probably recoat. If the surface is dry but still sticky then it's the perfect time. The recoat window will be longer in cold weather, much shorter in warm weather.

If you have no prepped the surface properly you will find that the POR-15 will peel off in sheets since there will be no adhesion.

One word of warning: DO NOT, UNDER ANY CIRCUMSTANCES, ALLOW POR-15 TO DRY ON YOUR SKIN. If you do, you will be wearing it for 6 weeks. Ask me how I know.

Additionally lacquer thinner and standard solvents will only clean it up when it is wet. After it has dried, only mechanical processes (ie. grinding wheel) will take it off.

t24todd

iTrader: (7)

did you get the kit from them..? i got the kit and you needed to spray it all down with marine clean then spray on the metal ready(zinc phospahate and let that dry then use there primer/sealer then mix the thinner in with the paint then apply...mine came out great and i think it was lik 50 for the kit...