[70chevellemalibu]

So with my car on the rotisserie i changed parts of my floor supports, inner rockers etc. I coated the inside of the new parts with POR15 and welded them in place how do i get to the backside to make sure that the rear of the welds are sealed?

Now that all my rust repair is complete i scuffed/sanded all my new parts and cleaned with marine clean and POR15'd my trunk pans, trunk supports and floor supports.

I decided to see how well POR will hold up to some light scuffing, and it start to peel off.

Should i sand down as much as i can and just prime and paint the whole underside as its been blasted.

Or should i re sand and re apply POR15 with POR15 primer?

thanks.

 

[Pete 67]

Strip the panels clean of all the POR 15, then throw the entire can into the trash.

Get yourself some good epoxy primer & spray 2 coats of it on all the bare metal once you're finished welding & grinding.

You'll be much happier with the results.

 

[6T7shovel]

between the panels use a good Weld through Primer, they usually contain some zinc which melts during welding, but protects afterward. clean any exposed areas and spray with good epoxy primer after.

 

[Bikerman9967]

Zinc rich primer has poor adhesion qualities so make sure whatever you spray it on , once it's welded you wipe off any exposed primer that may have oozed out when you welded the part. And like already stated. Throw that por15 in the garbage. It's nothing but a gimmick .

 

[Finally]

If you used POR-15 on new clean metal it won't stick. It's designed for use on a rusty surface. Surface needs to be clean of dirt, grease and rust scale but not clean bare metal.

 

[CoolBlueGlow]

+1 on what Hank said. POR = Paint Over Rust.
+1 on what Pete said too. Gimmick materials are to be avoided.

 

[jkwraase]

between the panels use a good Weld through Primer, they usually contain some zinc which melts during welding, but protects afterward. clean any exposed areas and spray with good epoxy primer after.

Note: Be sure to wear proper protection from metal fumes when welding on Weld-Through (zinc containing) primer. (Ask me how I know - Welder's Flu)

 

[NickeyChevelle]

I've used POR-15 extensively on several cars and have never seen what you describe WHEN POR-15 IS CORECTLY APPLIED.

 

[Raven1]

There are professional procedures and products available. POR is mainly used by those with limited resources and industry knowledge. POR capitalizes on it, just like Eastwood.

 

[Finally]

There are professional procedures and products available. POR is mainly used by those with limited resources and industry knowledge. POR capitalizes on it, just like Eastwood.

Maybe so but it's been on the frame and underside of my car for 20 yrs. No peeling, no chips and no rust.

 

[Beaux]

I'll use up the POR I have but after that its back to tried and true / proven paint.

Having stated that, scuffed clean metal should suffice, you would THINK.....but the ONLY time I have had POR fail on a small part / clean scuffed metal was when I skipped the etch with metal ready which is what you appear to have done. If you use POR use every step of the process - clean, rusted, scuffed metal - dont matter. Do every step.

Other stuff I have done is rock solid, no issues for years. But its just messy and I dont like POR OR Powdercoat for touch up / repair / fix blend reasons if needed.

 

[Bikerman9967]

I went to look at a used frame a few months ago. Didn't know it until I got there but he painted the entire frame with por15. Well as soon as I saw it and he told me about it I told him I wasn't interested and was on my way. He was offended and asked why I wouldn't want this frame because it was coated in por15. I walked to the rear crossmember and took my fingernail and peeled a 1 inch chip right off.

He started yelling at me because I ruined his frame. Guess a finger nail is too much abuse

 

[CoolBlueGlow]

I used POR-15 but I stretched it 2:1 with my own mixture of mineral oil, sawdust , three zinc lozenges and a pound of talc.

I called it POR 5.

True, I had to put three coats on to get back to POR-15 quality of protection, but I feel I came out ahead overall...what with the talc in there.

'Course at first I was unsure, but eventually I talc'd myself into it.

;-)

 

[70chevellemalibu]

i applied it on bare metal as per instructions from other members, scuff it up clean it and it will stick....

I was going to buy the metal ready but other members here and on other sites said that as long as it scuffed up it it will stick.

So either they are lying or never tired to peel if off. It is tough i can pound on it with a hammer and not scuff it but if i do get a area to lift i can grab it and peel it away.

 

[Bikerman9967]

People are lying to you about how por15 is a bad product ?

 

[70chevellemalibu]

either ppl are lying in that scuffing it up with sand paper is good enough, and that it worked for them or they never tried to peel it off.

Again it stands up to quite a bit, but if i get one spot to lift it just peels off.

 

[cheveslakr]

I've got a rotisserie, I built and let it sit outside a little gathering some rust....had some Por15 and decided to brush it without any prep work at all. It's been on there for 8 years, outside and is tough as nails to the touch. It has flattened or "chaulked" similar to an unprotected epoxy but WON'T peel. I continue to use it ONLY in areas I just can't get to with a blaster or abrasive. I reserve everything else to epoxy after proper prep.

 

[Tod74]

I don't doubt what people say about it lasting years and all that, but if I'm gonna take a car all the way apart snd do all that work, NO WAY am I gonna PAINT OVER RUST. I could see using it on something not taken completely apart but that's it.

I got my frame sand blasted for $75 and don't remember what the quart of epoxy was but it wasn't a lot.

How much does POR15 cost to cover a frame? I've never priced it.

 

[Coppertop]

FWIW, I typed up a lengthy use guide in 2011 after the same basic debate. To each his own, but I still argue most POR-15 "disasters" are the result of improperly using the product. Open the link and scroll to my post:

http://www.chevelles.com/forums/archive/index.php/t-356486.html

 

[70isfine]

POR 15 Peels and it comes right off when exposed to brake fluid. You would be better off and probably save a few bucks using epoxy primer.