My Experience with POR15
 

Morning all,

Thought I'd share my experience using POR15 since I answered a few questions about it on another forum. This is my first real project so I've been learning as I go.

I knew I had to take my body down to bare metal and figured I might as well use a strong rust barrier for any future issues. I called POR and they recommended their rust converter after making sure the body is clean. I bought their degreaser and a few gallons of their silver POR15 with aluminum powder to help strengthen some of the pitting. I sanded everything down with 80 grit flap discs on an angle grinder over the course of a month until everything was shiny bare metal. With a gallon of degreaser diluted 3:1 with hot water (instructions say dilute even further) I cleaned everything 2-3 times until it was clean enough to eat off of. I was told 80 grit was sufficient for a good coating bite.

Over the next week I applied silver POR15 everywhere, always within the temperature range (California) and always 2-3 coats within the recommended recoating window. It looked great! After that I did my bodywork for a month or two until I applied the 2K High Build Primer also from POR15. It worked great, coated well and very sandable. Then it was paint day. I'll skip over the issues here but bottom line I was unhappy with the quality of the paint job and decided to remove it back down to primer. A few stacks of 120 grit on a basic sander and away I went....until I noticed some peeling.

I dug a bit too low on one spot and a big paint chip flaked off...Odd I thought but hey I've never done this before. Inspected the area and felt around with my nail to make sure the rest seemed to have strong adherence. No. I was able to easily dig my nail underneath the POR15 and peel everything off in sheets roughly the size of A4 paper. No issues whatsoever, peeling everything from paint down to POR15 off of the metal with less difficulty than removing scotch tape from the surface. Within a few minutes all of my paint, primer, and POR15 rust barrier were in sheets on the garage floor.

Obviously I was extremely worried, did I have to strip EVERYTHING down to bare metal again?? I had purchased POR15 because of their reputation of it being a rock hard, very durable coating with extreme adhesion..and yet it had peeled off like tape. After a phone call to POR15 and sending pictures over they told me it was likely because the sanding had reduced the pore size in the metal and as such had made a barrier the POR couldn't adhere to without using their Metal Prep.

Being a Mechanical Engineer specializing in metallurgy (albeit for additive manufacturing) I called a few buddies who have more advanced specializations in Chemical Engineering and Metallurgical Engineering, all of them laughed at that response. So I called POR back and told them I don't accept that as a valid reason. To make it right they decided to send me a gallon of Metal Prep, a gallon of High Build Primer, and two sample kits.

So I began the long road of sanding all the paint and primer off down to bare metal so I could start again. My process this time has been:

Bare metal
Degreaser
Metal Prep
Etching Primer
Body Filler
High Build Primer
Paint

I was slightly annoyed because for a coating that is marketed as rock hard adherence, chip resistant, epoxy level toughness, etc. I experienced something very different despite working with an 80 grit roughed bare steel thoroughly cleaned with their brand of degreaser multiple times and left to dry in the California summer. The vast majority of people I've spoken to who have used POR15 did the same process I did and didn't come across any issues, but at the end of the day I'd rather have the awareness there for any future users. I can't say the Metal Prep resolved the issue because I'm no longer using their rust barrier and as of today I still haven't had any concrete explanations as to why it had next to zero adherence beyond the "pores in the metal shrunk" which I personally don't accept as a remotely valid reason.

Anyways in conclusion: do your research. POR has been great to me on a customer service level and I definitely appreciate them trying to make it right instead of telling me it was my fault and I'm out of luck. For what it's worth I would still use their products anytime I would just approach the process differently and be more selective on what gets coated.


Alex

https://cimg9.ibsrv.net/gimg/www.for...d20b72903c.jpg

So after all that work and ultimate failure....you are going to do it again????
There is no free lunch or "easy" way to do this. Stick to PROVEN automotive refinish techniques and materials. Yes it will cost more, but what is your time worth?
I don't use POR type products. Paint Over Rust is not a great plan to restore something, just a shortcut IMO.

Agree with Tinman, POR wouldn't be a good choice for exterior sheet metal.

Did you...did you just read what I wrote..? I literally said I would be more selective on what I used it on. You can take that smart ass attitude and walk right on out of my thread then bud. POR15 is a very commonly used product and was just trying to outline some of the issues I've had and what I'd recommend doing to avoid them in the future. No "proven" refinish techniques won't cost more...POR is way more expensive than self etching primer.

Great, you don't use them. Thanks for your super valuable input...

I've talked to the guys over at KBS and say either sandblast everything, or convert it and paint over the rust. They don't recommend a sanded clean surface at all regardless of grit...……

I am not that familiar with POR15 (I like KBS better), but it sounds like POR told you the same thing KBS told me. It apparently requires something with some extreme tooth to adhere to.

They told me it would adhere fine with proper prep. They even sell a direct to metal coating but not in a rust inhibitor.

I used POR on the frame and it came out perfectly; high gloss, very hard, and self leveling with the exact same prep. Maybe I just got unlucky on the body. Who knows.

At the end of the day this is a forum which should be to share knowledge with people who may be curious about other products so I'm sharing my experience. I would use their line of products but on different applications. Either way I'm moving forward and should be in primer by the weekend again.

Hey Alex,

You are completely out of line, sir. I read your words and wasn't certain of your solution - especially based on the last sentence. At no point do you clearly state what you'll do / not do on the repaint.

This is a supportative, positive place. If you want to berate other posters, find another forum. We don't behave like that here no matter how sweet a ride you have or how terriffic the project. We just don't.

Strongly disagree.

" I'm no longer using their rust barrier "
My entire post revolves around their rust barrier. I said I'm no longer using it. What part of that was confusing? They make something like 12 products. I would use their products especially the ones I've had success with..but I'm no longer using their rust barrier for anything body related. I was annoyed by tinman's response. I am making a general post about MY experience with Por15 in case any other user is curious and wants an actual first hand experience. What I got from him was basically saying I'm using shortcuts, taking the easy way, or a free lunch. No..POR15 is an established company making an array of products for auto restoration and machinery. They are widely used. I didn't need a smart ass response that really had nothing to do with my post. Again if you have the same viewpoint then post is properly and not come across like an ass. Four question marks like I'm an idiot? Give me a break man. Have a terrific day too.

I did a lot of research over the past couple of years to try to find the best products for my 51 F1 restoration. Many of the forums where serious body men congregate have a very anti-rust converter/encapsulator tone. Some of the members have experimented with the POR-15 and the other brands of rust converter/encapsulator and have documented their results, and none of them have been good. The general consensus appears to be that rust is rust, it must be completely removed, and there are a lot of snake oil cures out there that don't work.

Now, I am sure that there are hundreds, maybe even thousands of guys who have used these products and are happy with the results, so please don't start flaming me that it works and I don't know what I'm talking about. Maybe it does, but I saw enough real world proof that maybe it doesn't work that I ruled it out completely.

And given that the POR-15 failed for you in this application, I also wonder why you would use their other products. I know that I wouldn't.

HOWEVER, your truck, your money. If it makes you happy, go for it. Just be aware that others may see things differently.

On bare metal you need to use the metal prep before the POR-15. You need to clean the surface with the marine clean, sand ( I usually use 36 or 40 grit on the bare metal ) or sand blast the bare metal. Clean it again. Then use the metal prep. Without the metal prep the adhesion is going to be a coin toss.

It usually seems like the people that have the failures, are the ones that skipped a step or two on the prep. I've done it myself in the past. It's just like any paint product. Without the correct prep the results aren't going to be great.

Alex,
I concur with the others after reading your posts more than once and I feel the only, and I quote, ass here is you. You seem to be having a bad day, sorry for that.

In post #4 you said "I literally said" . No where did you make it clear what you where doing so what you LITERALLY said means nothing.

In post #8 you said "What I got from him was BASICALLY saying". What you perceived him saying to you was not directed at you as a slam but was a generalization of a fact we have all learned over time.

That being said your second paragraph in post #1 says it all to me. By your own admission you used it against their instrucions, " diluted 3:1...(instructions say to dilute even further)".
I obviously don't need to tell you what degreaser is because your a Mechanical Enginner, yes, you made sure to let us all know that not only in the body of your post but also in your signature. No where have I ever seen this done on this forum before nor any other forum I visit for that matter. So because of your degree you obviously know more than the engineers of the product.

You obviously have some education but at only 28 years old (yes, I looked at your profile) you have a long way to go in life experience and dealing with people.

So in closing, if you want to continue here, please learn to play nice and not attack members who have a great reputation and who helped many others with their questions in their chosen profession.

Best of luck to you with your truck.

Good luck with your paint job, sorry if I came across badly. I know absolutely nothing.

Alex,

It's water and grease, so you need to think organic chemistry and balance the equation, it's not like acids and bases, or solvents and reagents.
Check out how soap, grease and water interact on a microscopic level, it's very interesting Not diluting the degreaser as recommended actually forces some of the degreaser to stay on the metal.

FTE is a nice place, you can learn a lot here if you want to...

Jerry

I'm sure there are many arguments for and against.....I'm basing my "opinion" on 3 decades in the auto body biz. I will not paint over rust if at all possible.
Again, JMO....others can do whatever they want.