Hi,

It sounds to me like you're using a latex of water-based undercoat and then an oil-based top coat. Correct me if I'm wrong. Many times they tell us that you 'can' do that but I don't believe them. In my books if you want a good durable finish then stick with water or oil and don't mix them together.

Also make sure your plywood is untreated and completely dry before you do the finishing. Also make sure you coat each piece all the way around. If you have joints when you put the butterflies together make sure the inside of the joints are also coated.

Hope this helps. :)

Mark Saville is the owner of www.buildwithmark.com which is a documentation of over 30 years in building and renovating.

no i use only water base and it is not latex.

the top coat is a varnish for outdoor spar.

If you are not priming the wood first that could be your problem. You need to prime the wood (all sides and edges)with an exterior acrylic primer, but don't use one that is interior/exterior. You will be able to find this at your local paint store. Then you can apply you design and topcoat it with the oil based spar varnish (3 coats) and it should do fine.

I've been in the painting business for 25 years and I agree with the advice to use a primer, though I don't agree with the advice to use a latex primer or not to mix Oil primers with latex or water borne finishes. Oil primers can be "Top coated" with any type of paint. The best primer to use would be Benjamin Moore's "Fresh Start Alkyd" primer. If you want to use a "really big hammer", then use XIM's "Flash Bond 400".

Allow the primer to dry for at least 24 hours, though I usually allow 48 hours to be certain of a thorough cure. Sand with fine sandpaper to eliminate the roughness, clean the dust off and your problems should be cured