Varnish Problem

[viva]

I varnished various items on the boat last spring including 8 coats of LeTonkinois on the teak gunwhales. They looked great. I covered her up for the winter. When I took her cover off the varnish on the gunwhales looked awful with large patches discoloured and the varnish lifting from the wood. OK no doubt there was condensation under the cover (but there was ventilation) and no doubt there were drips from the underside of the cover pooling on the gunwhales. But shouldn't 8 coats of varnish stand up to this?
All other varnished areas were fine. Any advice?

 

[Woodlouse]

Certainly the varnish should have stood up better than that, especially if covered. How did you prep the wood before varnishing it? Might be that the wood was a bit on the damp side, or greasy. What ratio were the first couple of coats too?

 

[xtiffer]

See reply on the same thread in PBO.
Cheers,
Chris

 

[stuhaynes]

I varnished various items on the boat last spring including 8 coats of LeTonkinois on the teak gunwhales. They looked great. I covered her up for the winter. When I took her cover off the varnish on the gunwhales looked awful with large patches discoloured and the varnish lifting from the wood. OK no doubt there was condensation under the cover (but there was ventilation) and no doubt there were drips from the underside of the cover pooling on the gunwhales. But shouldn't 8 coats of varnish stand up to this?
All other varnished areas were fine. Any advice?

You have my deepest sympathy. I had this same problem and swore I would never use varnish again. I used 6 coats of yacht varnish on my 1950 Black Swan. Within a year it looked absolutely bl**dy awful! I've come to realise that the problem is the water content within the wood itself. As the sun does its stuff the water content is forced outwards, seperating the varnish from the wood. The varnish cracks and water can get in, making the problem even worse. I believe that unless the wood is kiln dried, or at least has a very, very low moisture content, you're asking for trouble. Not only that, to add insult to injury it's an absolute pig to strip off. I declared defeat and have used Ronseal ever since! (on the superstructure that is )

 

[sailorman]

I varnished various items on the boat last spring including 8 coats of LeTonkinois on the teak gunwhales. They looked great. I covered her up for the winter. When I took her cover off the varnish on the gunwhales looked awful with large patches discoloured and the varnish lifting from the wood. OK no doubt there was condensation under the cover (but there was ventilation) and no doubt there were drips from the underside of the cover pooling on the gunwhales. But shouldn't 8 coats of varnish stand up to this?
All other varnished areas were fine. Any advice?

was the cover canvas or plastic.
was the cover in contact with the varnish