Polyurethane Varnish

[Michael BordParticipant @michaelbord10152]

Hi Mattias, thanks for the tips on the varnish and paint, that's a very useful thread on the puffer build, just working my way through it. You've made a good job of it.

I'll report on how I get on with the varnish when it arrives.

[Michael BordParticipant @michaelbord10152]

I found an old tin of matt polyurethane varnish in the garage, rather old but seemed to stir up ok.

When the weather got a bit better I painted 1 strip of Vallejo RC Premium matt varnish (by brush) 1 strip of matt polyurethane varnish (brush) and 1 strip of Testors dullcote (aerosol can). This was onto a piece of polystyrene sheet with half painted with halfords grey primer and half with revel acrylic paint. Now the varnishes have thoroughly hardened, it looks as if

1) the Vallejo paint has dried very matt and has a very even and smooth finish.

2) the testors dullcote spray is nearly as smooth and almost as matt

3) the matt polyurethane is not quite as matt, not quite as smooth brushed but has a slight yellow/brown tint. Perhaps this is because it's varnish from a quite old tin but could still be ok if colour wasn't too critical.

Neither the Vallego or Testors varnish scratched with a fingernail so they both appear tough. The polyurethane I put on a bit thicker and may need to harden more but I could leave shallow scratches on it.

None of the finishes attacked the underlying paintwork.

Very impressed with Vallego applied with a brush, will also be very good for small parts for static models, but looking to spray it on hull. It's also claimed to be fuel proof, but that doesn't affect my model.

Useful thread, now found another good matt varnish!

[BanjomanParticipant @banjoman]

Hello Michael,

And thanks for your very interesting test report! I'm really glad to hear that you liked the Valleje RC Premium varnish, and I think you will find that it will airbrush on very nicely, too.

Please note that although it is, I am sure, nitro fuel resistant to the degree claimed by the maker, it will dissolve under methylated spirits!

I don't suppose that that is something you plan to apply to your hull anyway, but I thought I'd better mention it just in case. I have actually found this quite handy on a couple of occasions in order to deal with unevenly applied paint or varnish (shame on me for botching the job in the first place, but there you go), and also to remove a spot of paint to reveal the underlying material when I've needed to glue something to an already painted surface.

/Mattias

Edited By Banjoman on 29/10/2015 09:51:11

[Michael BordParticipant @michaelbord10152]

Hi Mattias,

re the Vallejo matt varnish. last wednesday theh sun was shining, it was still and the temp was 16 degrees c so i thought I'd give the hull a go. I used my basic Revell airbrush, with the varnish straight from the bottle. It seems to be a good consistency for spraying.

I was able to do the spraying in the garden, with the hull upside down on a workmate. Each coat seems to dry fairly quickly. I was able to apply several coats. The varnish went on very smoothly and evenly.

It's dried to a very smooth and matt finish, no ill effects on the underlying paint.

So thanks for the suggestion about this, I'll leave the hull for a week or so before doing anything else. Hopefully the varnish should be effective when the boat finally gets in the water, seems a tough surface.

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