POR-15

[Dieselman 63]

Does anyone have any experience with this? I was chatting to a fitter who says that when hardened fully, it will take the grit off sandpaper, take the metal off keys if you try to key it etc. Sounded amazing, but is it true?

 

[ajlelectronics]

POR-15 is excellent for the purpose it was designed for, which is for covering rough, pitted and weathered surfaces. On those nothing short of an angle grinder will shift it. However, what it isn't designed for is fresh, clean metal. Even with their own prep fluid, you can be fairly confident that it will strip off in sheets every time the wind changes.

Having been an enthusiastic user in the past, I would use epoxy primer now as I consider it superior on all surfaces.

 

[Dieselman 63]

POR-15 is excellent for the purpose it was designed for, which is for covering rough, pitted and weathered surfaces. On those nothing short of an angle grinder will shift it. However, what it isn't designed for is fresh, clean metal. Even with their own prep fluid, you can be fairly confident that it will strip off in sheets every time the wind changes.

Having been an enthusiastic user in the past, I would use epoxy primer now as I consider it superior on all surfaces.

I am considering it for a marine use.

 

[Burdekin]

It's rubbish. Much too fussy preparation required and after a while it will just peel off in large sheets.

 

[fizzy]

Use Jotun Epoxy paints - pretty good value.

https://www.smlmarinepaints.co.uk/primers

 

[rcx132]

Some people swear by it but if you go on YouTube you can see lots of videos of people showing what it's like after 5 years and describing it as not fit for purpose.

I'm sure it is hard as it's a PU paint but so are other PU paints.

I would consider it on top of epoxy primer though. Assuming POR15 is UV resistant.

 

[optima21]

about 10 years ago I used por15 on my car in some rusty areas and to paint a suspension strut that had newly been rebuilt.

and how it is today (after cleaning with a pressure washer) as I currently doing a rebuild, at the time the areas painted were abraded with wire brushes in a drill, and the rust was removed using the same method.

and you can see how it peels off

and the struts are just as bad

even to a point where the spring platform has rusted through.

Im using jotun 87 epoxy primer these days instead. hopefully it will last longer.

I would consider it on top of epoxy primer though. Assuming POR15 is UV resistant.

from memory its not uv resistant.

 

[Wallace]

That's not very good. I've been using Epoxy Mastic 121 on a rebuild, works well but only time will tell.

 

[slim_boy_fat]

Good job I never opened the tin of POR15 I have on the shelf, then. I can't even remember now what I bought it to do, but my cunning plan obviously became a 'Mk11'.......

 

[richie00boy]

I would consider it on top of epoxy primer though. Assuming POR15 is UV resistant.

Totally pointless on top of epoxy and will probably peel off. It only sticks to rust.

 

[Burdekin]

Totally pointless on top of epoxy and will probably peel off. It only sticks to rust.

When I first used it I did a trial, thoroughly prepped a piece of sheet steel as directed and painted it with POR15. The result was excellent. I stabbed it with a chisel and didn't come off, I bent the metal numerous times and still no issue. So I decided to use it on the floor of a car, prepped it as recommended and looked great. Couple of years later went to do some work on the floor and it just peeled off in large chunks. I'd say it's probably fine for short term but long term don't bother, it's not worth bothering with.

 

[rcx132]

Totally pointless on top of epoxy and will probably peel off. It only sticks to rust.

Ok. I was thinking that the epoxy would give the adhesion and rust protection and the POR15 would give the UV protection which epoxy fails on. But as you said, POR15 is not UV resistant.

 

[ajlelectronics]

Epoxy just goes a bit chalky eventually, but if that bothers you, paint it with anything you have to hand, even surplus car aerosol paint.

 

[bricol]

I discovered the epoxy paints worked well if the substrate was blasted to give a good key - nothing else did. ie follow the instructions ;-) I wonder if the POR stuff would work better on a good blasted surface?

 

[rcx132]

Epoxy just goes a bit chalky eventually, but if that bothers you, paint it with anything you have to hand, even surplus car aerosol paint.

The chalk then falls away exposing more epoxy until eventually it's got thru.

 

[rcx132]

I discovered the epoxy paints worked well if the substrate was blasted to give a good key - nothing else did. ie follow the instructions ;-) I wonder if the POR stuff would work better on a good blasted surface?

Doubt it. Epoxy etches itself into the metal creating chemical adhesion . POR probably doesn't which is why it can only go onto rusted metal to get a mechanical locK.

 

[fizzy]

The chalky surface on epoxies is more a visual problem than a structural one.
I did some IT work for a company that used to paint bridges with epoxy paint. They did several along the M4 corridor back in 1993 - looked closely at one yesterday and the paint still looks fresh. they were using Leigh's paints - a British company now taken over by Sherwin but still made here. I had some for my 110 - amazing stuff. I was going to buy more for my trailer until I saw it is now £195 v £50 for Jotun!

 

[rcx132]

The chalky surface on epoxies is more a visual problem than a structural one.
I did some IT work for a company that used to paint bridges with epoxy paint. They did several along the M4 corridor back in 1993 - looked closely at one yesterday and the paint still looks fresh. they were using Leigh's paints - a British company now taken over by Sherwin but still made here. I had some for my 110 - amazing stuff. I was going to buy more for my trailer until I saw it is now £195 v £50 for Jotun!

Fair enough, though I thought someone posted on here recently how they did the underside of their car using epoxy and the paint itself was deteriorating due to being a primer and being exposed. Still, primer is an undercoat, if you look at the Jotun brochures, they say it's the topcoat that gives not just the UV protection but also chemical resistance and abrasion resistance. I always put a topcoat on, but the topcoats are a pain as they contain isocyanates.

 

[fizzy]

It depends which primer you use. The Jotun 87 can be had loaded with aluminium or glass flake which is suitable as a finish coat as well as a primer.