two-part poly over varnish

[12reasons]

I'm repainting a doug fir box mast and thinking of white from the spreaders up and varnish below. Will two-part poly stick to varnish or should I prime first?

[Chotu]

I know there are a lot of experts here, but this is one case I think I would call the manufacturer. I have made plenty of mistakes thinking things would work like this. The manufacturer always knows what to do. They know the compatibility better than anyone else. And they can even help you with some tips on surface preparation.

[Nicholson58]

Originally Posted by Chotu

I know there are a lot of experts here, but this is one case I think I would call the manufacturer. I have made plenty of mistakes thinking things would work like this. The manufacturer always knows what to do. They know the compatibility better than anyone else. And they can even help you with some tips on surface preparation.

I agree. I’d start with the instructions on the can and go on line for the product if you need more definition. I know that two part over single component paint is a no no. I’m sure you’d rather do this only once.

[David M]

Agreed, two-part poly is much tougher and might even partially melt the single as it is being applied. I don't think any two-part poly manufacturer will recommend the application over a single part varnish....but maybe with a compatible primer in between.

[gonesail]

if the varnish fails it will peel. why not just take the varnish off?

[picklesandjesse]

30 years ago we bought a boat in Marion Ma that was finished with Sterling which is/was a two part system. The hull was finished bright and looked beautiful. Below the Sterling there were 6 coats of Epifanes varnish that was a conventional varnish. It had been allowed to cure for 3 months before the Sterling was put on. So I believe that you can cover a conventional paint with two part if it has been on long enough and is fully cured. A few years later I stripped the hull back to bare wood and did the same thing in a boathouse near Vancouver BC and it worked out just fine. This time I used Captains varnish and finished with Awlbrite clear. Was still good 10 years later when the boat was shipped back to Sweden bought by the son of Peter Norlin who had designed the boat. Agnes is still around !!!! Pic shows her before first launch 1975. That boat went to weather like crazy !!

[mickand]

3 part Awlbrite polyurethane is compatible with oil based varnishes

[picklesandjesse]

Originally Posted by mickand

3 part Awlbrite polyurethane is compatible with oil based varnishes

After a few months only !!!! Sorry, should have made that clearer.

[Wotname]

Originally Posted by 12reasons

I'm repainting a doug fir box mast and thinking of white from the spreaders up and varnish below. Will two-part poly stick to varnish or should I prime first?

I'm confused

What sort of two part poly are you referring to?

Polyurethane
Polyester
Poly-something-else

[Tingum]

The reason for varnishing wooden masts is to be able to see any rot forming under the varnish. This would be impossible under white paint. I would also be concerned about moisture penetrating any cracks in the two part paint, which is much more brittle and les flexible than varnish. Remember your mast bends.