Thread: POR 15 Paint

Garry, did you use Marine Clean to pre-treat before applying the primer. I've usually found that not doing this is the culprit.
Also you can use the KBS range which is effectively the same polyurethane product but Australian. Apparently POR 15 was developed in part by an OZ engineer in the US who has subsequently returned home and started up his own formulation - urban myth or??

No Marine Clean used but the area painted where it bubbled was new fresh clean metal - the area that was rusty worked fine.

Thanks

Garry

I use the chassis black[not uv tolerant] and it is great with out any problems, there aluminium silver heat paint is good to[on my 300tdi engine block so i can see oil leaks and on motorbike barrels] but i wouldnt reccomend there tank sealer.
Richard

The polyurethane paint cures by absorbing moisture from the atmosphere, any water will cause a very fast cure resulting in gassing and therefore bubbles. This I thought could also occur if the polyurethane was applied too thick as the outer of the paint would cure before the inner had finished releasing gas. Apparently some thinners can have moisture in them resulting in bubbles. KBS sell you their own thinners to avoid this problem.
I know POR 15 tank sealer is sloshed around inside petrol tanks and therefore could potentially be quite a thick coat.

When you say used according to instructions, do they recommend acrylic? I would have thought that acrylic would contain water and therefore would not be recommended for use together with polyurethane paints unless the previous coat was fully cured, not just tacked. I know that waiting for the polyurethane to tack off is the way to apply more coats but I thought that it would only be with other products without water in the formulation.

I am by no means a paint expert so take it with a grain of salt, I have yet to apply the KBS that I purchased over a year ago and am only going by memory of the instructions.

Originally Posted by slug_burner

This I thought could also occur if the polyurethane was applied too thick as the outer of the paint would cure before the inner had finished releasing gas.

This may have been the reason as it was on thick

Originally Posted by slug_burner

When you say used according to instructions, do they recommend acrylic? I would have thought that acrylic would contain water and therefore would not be recommended for use together with polyurethane paints unless the previous coat was fully cured, not just tacked. I know that waiting for the polyurethane to tack off is the way to apply more coats but I thought that it would only be with other products without water in the formulation.

Instructions indicated all paint is OK to go over the top and that it should be painted just after it has tacked off and not dry. I would not have thought acrylic would have had water in it.

Cheers

Garry

Originally Posted by garrycol

This may have been the reason as it was on thick



Instructions indicated all paint is OK to go over the top and that it should be painted just after it has tacked off and not dry. I would not have thought acrylic would have had water in it.

Cheers

Garry

I must of been thinking of water wash up house paint as acrylic but don't know why. Off the top of the head thought without supporting research.

Now I remember I did paint something in Dulon once and I think that was an acrylic that used thinners of some type to cut it down to spray and wash up.

I used the "tiecoat" (what amazing coverage!) over por15 then top coated

PPC • Restoration Specialists • Coatings • Tiecoat

It would have been the solvent in the acrylic under coat reacting with the poly paint 2 different types of of paint . the drying times of both paints are different.