Thread: any experience with por 15 or KBS coatings

I used it just over a year ago on the complete bare chassis (frame) of the Triumph Spitfire I've restored.

Bit of a hit and miss experience actually. I wanted the POR15 because of the ability to overcoat it with another colour / paint as the Spitfire chassis' are body colour, which in our case is yellow. Stripped the chassis to bare metal and I'd advise you do this, POR15 doesn't like a rough rust / dirty / greasy / oily surface. I also went the whole hog with the full recommended cleaning process (look on Classic car restoration, Kit Cars & motorcycle restoration tools and equipment | Frost Auto Restoration Techniques, where I got mine from, all the instructions are there) so in all it took me about 2 weeks to clean, prep and paint the chassis.

Once it was painted, I let it harden for the specified time, then sanded down ready to paint it body colour. On applying the primer, by the time I was halfway along the chassis the primer where I'd started had started to react with the POR15 and within 5 minutes everything I'd primered was ruined, the POR15 was bubbling up. Took a scraper to it and it went straight back to bare metal. Cue then another week of prep to get it back to bare metal and shift the reacted paint. Re-applied the POR15, went on holiday for 2 weeks, came back and painted it body colour, this time with only a couple of small areas of reaction that I can live with.

The sections that are left in the black POR15 look stunning and to be honest, I wish I'd not bothered painting over it, but it would look ridiculous. As a product, if you follow the instructions to the letter then it's great, seems to be very hard wearing but I would caution on the hardening time, certainly for me it took a lot longer than the instructions state. I queried the reaction with Frost and they couldn't help, just said "it shouldn't do that mate".

Hope that helps
Mike

I understand POR is not UV stable so can only be used in areas that will not be exposed to the sun or reflected sunlight - needs to be overpainted for protection but does have compatibility issues as raised above.

Garry

I had a play with the KBS stuff on a set of side rails for the 130.
It really was just to try it out for further projects.

Firstly, great company to deal with.

So this was a new steel project, standard black pipe primed. By the time it was finished welding there was flash rust in places etc I didnt sand the primer back to bare metal but removed flash and hit all surfaces with the flapper. Used the KBS system (essentially phosphoric acid etch) then the KBS rustseal, 2 coats.

It goes on thin and wicks into all the joints and crevices. As they say it isnt UV stable which is kinda nice as when gloss it is scary blinding bright gloss!!! It has now faded to satisfying dull black grey which goes with the beat up look of my fender. It is truly good stuff that is tough and hard wearing.

Interestingly in one place I overcoated with standard Rustgaurd black, satin. No issues with adhesion or reactions. And obviously the Rustgaurd doesnt fade to grey!!!

Also interestingly, I overpainted the bull bar with no prep apart from a quick rinse off the mud (a test you see). The powdercoated bar was in knocked around condition with rusted scratches etc etc. The KBS has stuck just a well to unpreped powdercoat and rust as it has to prepped bare steel.

It seem to be good stuff so far (about 6months abuse thus far) and I would definately use it again.

S

I have used both products on Land Rover restoration. As mentioned above, you need an oil clean dry surface. No problems painting over light rust.

The biggest hint is to wear gloves as if you get either product on your skin it takes an age before you can get it back off.

Both companies now make a UV stable product in limited colours.


Erich

POR15 - don't paint on a hot day, don't paint in full sun, goes off very quicky.

It may be a furphy, but I've been told that the Aussie who initially designed POR 15, then set up KBS on his return to OZ.

I have used both with great success. Once dry, doesn't come off - just wears off your skin. As elsewhere, follow suggested uses and instructions religiously and yes read the fine print on UV stability.

I have used the black, white, green and finally the silver/grey which turns a lovely light slightly green tint after a while. KBS say don't overcoat it above rustseal - claim there is a real risk of separation as rustseal is a "budget product made to a price".
Yes you can use it for its rust conversion/holding properties and then overpaint it with other "paints".

Used some POR15 Fuel Tank Sealer seems to be great stuff just dont get it on yourself.
Still actually have one silver toenail and my dog still has one silver foot lol

Use only on pitted or prevoiusly rusted sections, welded rough area etc. On clean(as per manuf instructions) lightly stuffed metal it will peel off in sheets.

Underbody Finishes - MIG Welding Forum