tinting PU varnish ?

Hello All,

let me first say, thank you all for offering such a broad band of knowledge at a public place, here!

Does anyone of you know a product to tint 2k PU varnish and the possible disadvantages?
We try to apply the top finish on a Cabin cruiser superstructure to remain transparent (it is wooden), but like to have a transparent colouring, instead of staining the wood.

Any hint would be much appreciated.

Thanks Sasha M.

 

Hello, and welcome on board!
Are you going to apply the varnish directly on the wood, or is the wood coated by Epoxy resin? And why not staining the wood?

Regards
Richard

PS Alexander? You are in Germany?

 

Yeah Sasha, staining the wood is a lot more even. The clears then protect the onderlay, tinted varnish is not such a good idea, especially if it needs repair at any time.

 

Thank you both for your replies.

The PUR varnish is to be sprayed over Epoxy coated veneer on plywood. We do not like to stain because it´ll get to dark. The effect shall be like looking through a tinted glass. Maybe this is a better description of what we like to achieve.

 

M Sasha,

Could you enlighten us more, why epoxy coated veneer, do you mean fibre reinforced epoxy, such as Dynel of GRP, or do you just mean you are going to paint the veneer with epoxy.

If that is the case, do not do that, simply using Poly varnish will do all the waterproofing you want if that is the sole purpose.

We used to use clears over veneered surfboards and small sail boats, long ago, they were simply fantastic to look at .

 

M-Sasha, your post makes perfect sense to me. Tinting PU or any other clear coating can be difficult to apply evenly, so work with very subtle amounts and build up color. I've employed this technique to match repaired areas.

Depending on the polyurethane clear you're using will determine what type of pigment to use. In most cases you can use the same as used in oil based paints. If the PU cleans up with mineral spirits then you're likely safe to use regular oil base pigments. If it's a water born PU, then use an acrylic pigment.

Practice on scrap first, because these pigments go a long way, just a few drops per quart can render a cloudy mess. Spraying patterns also have to be practiced as overlap will produce slightly more color then the "field" areas. Attempt to just butt spray pattern edges, rather then the typical 50% overlap. Subsequent coatings will cover any zebra stripes. In fact I'd use a cross hatched approach, with horizontal passes, then vertical passes to prevent zebra stripes.

 

Thank you very much PAR. Especially for the spray pattern, we tested to spray with a cheap tinted varnish and the result was not perfect due to (minor) overlapping problems.
The PU we use is acrylic based. Do you have any brands to recommend?
We are covering the veneer with Glass Epoxy, then we like to build up some ten or more layers of very slightly tinted PU varnish to get a Glasslike look. With a good spray pattern it should be possible to get an even colored film, because every single layer is slightly colored only and the Epoxy surface is sanded to give a even surface first.
Do you use the clear PU filler?
We are not staining, it makes the veneer look to even, or say artificial, and it tends to make "schlieren" in the Epoxy film.

ciao
S. Medwedew

 

I wouldn't use a water born PU, instead I'd use a water born LPU, which will produce a harder, more durable finish. You have to be careful with the water based stuff as they have so many modifiers in them, anything can screw with their cure rate.

Call the manufacture of the PU you're using and ask for pigment recommendations.

If no luck there, drop me an email (click on my name) and we can discuss the options and products I've used.

 

Alexander, send me a mail if you´re in Odessa, I´ll rush over then for some ..../... at Londonskaya.


Paul, is:... LPU, which will produce a harder, more durable finish.......
not a bit less glossy than other sorts of PU varnish? I think I remember such statement from the past!?
Alexander (Sasha) is using whatsoever is available in Ukraine, even if based on catpinkle. He is an old friend, I´ll see him next weekend.
I am very much interested in this issue and would like to discuss it in deep with both of you.

Regards
Richard

 

The WR-LPU's can be buffed up to a high luster, though out of the can they aren't as "bright" as the solvent based LPU's. The single part PU's just aren't as durable or as hard as the linear versions, though for non-high traffic areas, they'll be fine. Give me a call Richard, you should have my number, if not drop me an email.

 

Thanks Paul, I´ll choose the mail, cos my mobile generates bills in the €2000 ballpark already (roaming in Turkey)!

To topic, I think we should also bear in mind that we have to have an eye on the elasticity of the varnish! The intended use is outside!

Regards
Richard

 

Thank you all for your kind assistance!
İ believe that we can find a solution with car varnish on the superstructure.
Special thanks to PAR and apex.

Sasha Medwedew