Advice on mastic

[phil58490]

I have a grp Finn, it has hard wood capping to the gunwhales which are screwed in place on a bed of black mastic. The mastic is now hard, brittle and falling out so needs to be replaced. The mastic fills the gap between the bottom of the wood and the hull, is 6mm thick and obviously was used to seal the deck to hull joint.

Suggestions and advice as to what I should use, thanks.

[Obscured by clouds]

I'll be interested in an answer too since I will probably have to do something similar to mine [Taylor]. Have you posted over on the Classic Finn Forum? http://classicfinn.org.uk/

[Ed]

Sikaflex.

I think the one you want is: 291

http://www.sealantsonline.co.uk/Product ... es/SIK3290

or possibly, you might get away with 221

http://www.sealantsonline.co.uk/Product ... lyurethane

Be aware the 291 is wicked stuff. You won't find it easy to change your mind once it has set, so do make sure you get it right. It is black and gucky and very tough.

I once made the mistake of smearing the bottom of some fittings in the stuff before putting them on a varnished deck. Couldn't get them off again. When I finally managed to remove one, it took a whole veneer of the ply away with it.

The 221 is not so strong, but you can get it in white. Good as a sealant, but does not have the same amount of glueing strength.

cheers

eib