Teak Seams Filled With Epoxy/Graphite

[benjiwoodboat]

I'm refinishing the hatches on my BCC, and they are teak strips laid up to look like deck, with seam compound between the planks. There is a plywood base underneath it all.

I'm considering filling the seams with epoxy/graphite, and doing away with flexible caulk, which is by nature of its flexibility is bound to put cracks in my varnish over time. I don't need the non-skid benefits of flexible caulk, and I want to varnish these hatches.

Any one have any good reasons why I shouldn't do this with epoxy/graphite?

The hatch is ready to be filled...

[catty]

Originally Posted by benjiwoodboat

I'm refinishing the hatches on my BCC, and they are teak strips laid up to look like deck, with seam compound between the planks. There is a plywood base underneath it all.

I'm considering filling the seams with epoxy/graphite, and doing away with flexible caulk, which is by nature of its flexibility is bound to put cracks in my varnish over time. I don't need the non-skid benefits of flexible caulk, and I want to varnish these hatches.

Any one have any good reasons why I shouldn't do this with epoxy/graphite?

The hatch is ready to be filled...

Don't do it. Having used the epoxy graphite system on a cat boat deck at the product suppliers ok, I found that within 12 months the swelling of the 6mm thick planks glued to 9mm ply had caused cracking and a horrible mess. Youve got to do the job properly with sika primer, bead breaker tape and sika. Since this disaster I have seen many other attempts at this epoxy/ghaphite system with exactly the same outcome. If you intend exposing your handiwork to the elements use sika.

[blue merlin]

Can someone explain to me why the breakaway tape is necessary on a teak deck laid on GRP i.e. for decorative purposes? - Any ideas welcome.

[benjiwoodboat]

It's very helpful for removal of the caulk when the time comes - and I will use it on my hatches when laying in caulk again. When I removed the caulk on my hatch, I cut the sides with a razor blade, and then pulled the caulk out in one piece -- very easily. The bond breaker on my hatches was a soft grey, twisted yarn looking chord. Pic shows it stuck to bottom of caulk here.

Originally Posted by blue merlin

Can someone explain to me why the breakaway tape is necessary on a teak deck laid on GRP i.e. for decorative purposes? - Any ideas welcome.

[benjiwoodboat]

Thanks Catty, this has been the concern, looking for folks experiences with the failures of this route. Appreciate the report. I really think I'll caulk.

Originally Posted by catty

Don't do it. Having used the epoxy graphite system on a cat boat deck at the product suppliers ok, I found that within 12 months the swelling of the 6mm thick planks glued to 9mm ply had caused cracking and a horrible mess. Youve got to do the job properly with sika primer, bead breaker tape and sika. Since this disaster I have seen many other attempts at this epoxy/ghaphite system with exactly the same outcome. If you intend exposing your handiwork to the elements use sika.

[GordMay]

No, not just aesthetic - Bond Breaker Tape (bead breaker) is used to prevent “three-sided” adhesion in small or flat joint designs.

A sealant which bonds to three sides of a working (dynamic) joint is subject to cohesive tearing when significant cyclical movement occurs. Backer rod and bond breaker tape with non-stick surfaces prevent three-sided adhesion in conventional joints. Bond breaker tape is used where the joint is not deep enough to allow the insertion of backer rod.

See:
http://www.masterwall.com/files/mw14...lantdesign.pdf

[Wotname]

Gord is 100% correct. I have tried with and without breaker tape. The caulking bond fails very quickly if the tape is not used.

[Wotname]

Originally Posted by benjiwoodboat

<snip>I'm considering filling the seams with epoxy/graphite, and doing away with flexible caulk, which is by nature of its flexibility is bound to put cracks in my varnish over time. I don't need the non-skid benefits of flexible caulk, and I want to varnish these hatches.

Any one have any good reasons why I shouldn't do this with epoxy/graphite?

The hatch is ready to be filled...

While I agree with Catty etc if your are just varnishing the surface (or even leaving it uncoated); you can use the epoxy graphite mix if you SEAL all the surfaces of the hatch with epoxy resin (using a UV stable hardener) and then overcoating with a 2 pack exterior poly clear coat.