Wednesday, November 20, 2013

Primers

I have to write this down before I forget. I have tried a whole bunch of primers now. Monopol wash primer, Monopol Strontium chromate epoxy primer, Scanox rattle can (no longer available), Biltema aluminium primer, Duplicolor aluminium primer, Duplicolor plastic primer, some old zinc chromate primer, Jotun Yachting rattle can Vinyl primer and Jotun Yachting canned vinyl primer. I have also tried rattle can top coats.

Biltema and Duplicolor gives a very nice finish and are very easy to use. They look really nice, but when testing physical and chemical strength they are extremely poor. A drop of acetone will destroy large areas.

The Scanox (quick) rattle can is a bit more difficult to use, but it is much stronger physically and chemically than Biltema/Duplicolor.

Monopol wash primer is really good. It is for professional use. But the surface is porous and therefore it must be covered with something. As a primer for outside top coat it is probably as good as it gets. But it really is not something to use inside the house, the VOC content and odor is beyond belief.

The Strontium Chromate Epoxy is the best overall. Extremely strong, yet only 10-20 micrometer thick, and can handle even Acetone in moderately amounts, and is totally corrosion proof. But, it is not for the house due to VOC and toxicity and it is a lot of work.

The old zink chromate rattle can is easy to use, but it is thick and not very strong. It is also practically impossible to get.

The Vinyl primer is a bit difficult to use from the rattle can. But when cured over night it is very strong, and it even handles acetone to some extent, not nearly as much as the epoxy, but remarkably well. It is the only one together with the epoxy that is 100% waterproof. It can also be brushed on, and this is really practical when priming only the mating surfaces. In addition it can be used everywhere, on all substrates, and it is non toxic. And of course, it is part of Jotun Yachting system with the Polysiloxane top coat and is available everywhere around here. I just hope the rolling of the polysiloxane turns out OK.

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