POR-15 ?? can i prime the whole car with it?

[PocketThunder]

I bought a quart of por-15 and primed the whole bottom side of my 68 and the rear end this past weekend.  this stuff was awesome!  it says in the directions that i can epoxy prime over it.  So i'm thinking, can i prime the whole car with por-15, then epoxy prime, then filler prime, then seal it, then paint it?  I dont see why not but maybe someone (Drop Top) knows better... 

Thanks
PT

[Dans 68]

Until Drop Top shows up let me offer something. I have read (on a now apparently  defunct forum) that Por-15 is used to prime and seal areas that have at least some rust damage. If you use this stuff on non-rusty areas you may have a problem with adhesion...the Por-15 may just let go after it dries and peel off in sheets. Not fun.

Is Mr. Drop Top lurking?

Dan

[Troy]

I don't think Drop Top is around yet. I'll send him an email.

On the subject though, I would NOT use Por-15 as a primer. That wasn't what it was designed for and as long as the metal is prepped properly I think you'd be much better off using epoxy. Por is designed to go on rusty areas (in places that you probably aren't going to fix the right way). I'll have to find the rest of the info later when I have time.

Troy

[Silver R/T]

if you want it to peel, theres lots different primers than por and sometimes cheaper too, why would you want use por, just use good quality etching primer on bare metal or epoxy primer over metal/bondo

[69hemi]

The best bet is if you have bare steel then you need to use an etching primer then epoxy then high build.  The etch will grab onto the bare metal so the epoxy can stick to it then you use the high build to fill, smooth & shape the surface.

[PocketThunder]

thanks guys,  i'll pass then on the por-15 idea.  just had to ask since it worked so well on the bottom side.... 

[Silver R/T]

or you can use epoxy primer over filler/bare metal and then use filler primer like PPG's K36. Try not to spray etching primer over bondo

[MGBRingo]

You could use POR 15 to prime the whole car but you do not need to.  Just do like others have suggested.  I have used POR 15 on large areas of trailers and cars as primer and it has lasted for years.  Have not seen it peel anywhere.  It is expensive as a primer though where you don't need it to stop rust.

[B Bodyman]

por15 has it's own primer designed for color coating,it's called ty-coat primer,it go's over the por15,and won't peel,then you can use any topcoat colors,,but never use it on your body's exterior,as the main primer,when I media blast an entire car on a rotisserie,I use an etch primer,followed with several coats of 2k high build,no need for epoxy over etch.,if the car has only been sanded down,and still has good previous paint,and old body filler in good shape,then I use epoxy,as etch will crowsfeet crack over some older enamels,and clearcoat residue. this 68 will get epoxy,as alot of the black paint is still good and will just be scuffed,I blasted all the window channels and tail panel engine bay etc. to make sanding non-existent,and start fresh,,and the nice thing about epoxy is you can do bodywork under or on top of it.

[B Bodyman]

better pic,

[superbirdtom]

I live in ketchikan Alaska where we get 200 inches of rain a year por -15 does not last here for anything. I always etch prime bare metal then use ppg dp-50 grey epoxy you can do your bondo work over the top of that . bondo (plastic) adheres better to that than to bare metal. i have been doing body and paint professionally for 30 years -even worked for gene winfield.  then after bondo work reseal with etch and epoxy and then fill prime with k-36 high build primer . I have seen cars that were restored down south come to this rain hole and explode with rust after 4 years. we here in alaska have proven methods for making things last. I have also painted over 100 aircraft so I knoe how to make things stick. don't waste money on por -15.   superbirdtom

[c5_nc]

I think the smith brothers (general lee builders) are using clear por-15 as a primer, apparently successfully.  If you go that route (which I probably would not) they maybe able to give some pointers on how they apply it.

[bill440rt]

The POR-15 office/warehouse is about 40min from me. I spoke with several people there when I bought some for my project.
POR-15 will not stick to smooth metal. A rusty, or rough surface is preferred. My '69 was sandblasted first, & I used it only on the undercarriage, suspension, & interior metal of the car, underside of the roof, etc. It has adhered very well to the clean, rough sandblasted metal, & has not come off even when hit with a hammer.
When painting, I used POR-15's Self-Etching Primer over the CURED POR-15, topcoated with urethane enamel (Omni by PPG), & that has  stuck well even after a duct tape test. If duct tape didn't pull the paint off, I'd say it sticks pretty good.

I do not recommend "priming" the exterior of the car with POR-15. I definitely recommend using PPG's epoxy primers as others have suggested. DuPont also makes an epoxy primer.