Mooser

Just wondering if anyone has used regular self-etching primer on POR-15 as opposed to their own version (at $37/can)?

Also, has anyone tried powder coating over POR-15? I know they powder coat over epoxy paint (trailing arms etc). Will POR hold the static charge?
Hate to waste time trying it if someone else already knows

Any the obvious question, why? I've got some smaller suspension items that were POR coated (last year, no exposure, no top-coat) and while everything is apart I want to give them a top-coat / color change so it's either etch-prime and paint or a trip through the P-Coater

Just wanted to hear from anyone who's actually tried either
Thanks

Nowhere Man

why would you powder coat of POR 15. its one or the other. to me I would never use that stuff on a frame again.

UberLegend

HamadUP

You mean POR15? why? whats wrong with that stuff?

Clubby99

POR-15 chips easily. Also only adheres well to rust which I always remove. Need to etch with "Metal Ready" on clean metal. POR-15 is too expensive and overrated.

Best used on rust buckets.

Nowhere Man

I used POR15 on my chevelle frame I restored. for one its very easy to chip and scratch. the stuff is to thick and does not look very good in comparison to powder coat.

Mooser

If you re-read the post you'll see I already have a couple of brackets that are painted with POR15 and wanted to change the color.

Yes I can blast and start from scratch, just looking at other options.

Steve2147

You don't want to etch prime. Etch uses an acid to bite into bare metal. if there's a coating over it already the etch does nothing for you. You'd be better off using an epoxy primer if you feel the need for additional adhesion.

Whatever you do you need to thoroughly sand/abrade the pieces. If they are parts that are difficult to get into the nooks and crannies I would blast it and start again.

For small parts like that where sanding is not really easy or practical what I recommend doing is media blasting, clean thoroughly, apply a coat of epoxy primer then your top coat within the epoxy's recoat window.

Epoxies are like contact cement, they glue your top coat to the metal. You apply it, let it flash off then apply your finish with no sanding in between. And just like contact cement, if you let the epoxy sit too long before top coating it you will lose the adhesion. It must then be sanded and started again. Fortunately most epoxy's have a recoat window of 1 to 3 days or even more. Unfortunately it is a two part product and requires the use of a compressor and spray gun.

Steve g

Mooser

Thanks Steve
Here's a link to POR's etch primer
http://www.por15canada.com/can/primer.asp
Their sales blab

"With this product, you can even top coat POR-15 that’s been in place for months or years.
POR-15 Self-Etching Primer is NOT a high-build primer, like POR-15’s TIE-COAT PRIMER, but it can be sprayed or brushed on almost any painted surface and can be top coated 30 minutes later. It bonds incredibly well to POR-15 Rust Preventive Paint, and all top coats bond incredibly well to POR-15 Self-Etching Primer. "

So I take it to mean it etches the cured POR and allows the paint to grip. Many posts and people say painting over cured POR just flakes off (I've never tried)

Since the parts (and only a few) are in good shape and I just wanted to top-color them, I thought this is a good item, but at 3x the cost of normal etch primer I'm kind hesitant.

I think I've got some cured POR on something in the shop somewhere, guess I'll do some experimenting.

Normally when I do use POR (not often but it has it's place) I will topcoat when it's just about dry (slightly tacky) and it has always bonded very well.

Gives me something to do tomorrow
Thanks again
Mooser

Steve2147

A poor choice in a name I would say. Etch generally refers to the affects of acid on a material (concrete, glass, metal etc). Most paints are not affected by acids. I would not substitute any other kind of etch in place of theirs as this is not what etch primers are intended for. If their product forms some kind of bond with their rust paint I would go with that.

Steve g

Mooser

Well just for future reference
I took some dry POR-15, wiped it off (wax remover) and sprayed it with a coat of Dominion Auto self etching primer (gray) meant for aluminum and such.
Let it dry (actually kind of forgot about it for a few days)
Stuck like the proverbial S&#t to a blanket

Tried scratching it, chipping at it, sanding it. doesn't flake at all, even right on the edge of the scratch that goes through into the POR.

I'd say it works just fine for preparing cured POR15 for over-coating

I also tried just painting some Krylon right over some POR-15 (cleaned as above) with no primer
Stuck pretty good but you can see at the edge of the scratch where it's jagged and is actually flaking off in very small flakes. Not as good as with the etching prime.

Didn't try regular primer, may do that just to see.

Mooser

Indiancreek

If the prep that is required with POR15 is used it is on for the duration. Where problems happen is when short cuts are taken. The metal reday is a must.
If it's on and cured, red scotch pad it and paint. Use a good brush or foam roller. A cheap brush will leave streaks.
A good chassis look requires the POR15 chassis coat. Just POR15 will fade in sunlight over time. Chassis Black is UV protected.