Adhesive/sealant

[Grumpybear]

I am trying to rebuild the pivoting helm seat (which moves to become a step down to the sugar scoop). It consists of a GRP shell with teak strips glued to it to form the seat. When inverted the step is made from more teak strips; the space between top and bottom was filled with an inch thick slab of plywood attached to the undersides of the shell and the teak step by some form of black mastic sealant which also seals around the edges (or, rather, it doesn't, as after 15 years the step has fallen outOf the GRP shell attached to a gooey rotting mess of plywood gunge).

Removing this and cleaning up made me realise just why classic boat fans are so devoted to their vessels - the stench and texture of rotting wood are really quite addictive (not).

The real reason for this post is to ask advice on what to use to reassemble the step. I have found a slab of mahogany which will do for the filling, but what sealer/adhesive would the panel recommend, please? Colour black to match the caulking of the teak strips.

Many thanks in anticipation

Gles

 

[PCUK]

Sikaflex or Saba or any other polyurethane sealant.

 

[Lakesailor]

I Have just experimented with different adhesives for joining ply to grp. The bits of ply were stuck, on edge, to the grp.
One of the adhesives was Saba.
Yesterday I stepped back onto one, which came away. It was the one using Sabatack 750XL. I thought it must have failed. Lokking closely I saw that the adhesive had not failed. It had torn the ply veneers from the piece of wood.

See my test video from a year ago.

 

[Grumpybear]

Many thanks to you both. Decided to go with Sikaflex as Sabatack is not available locally and I'm in too much of a hurry to wait for delivery!

 

[Lakesailor]

The performance is probably similar if you choose the right one. Probably 292.

The Sabatack has the advantage of staying viable in an opened tube for 6 months or more. The one I described earlier was the dregs of a gun tube that had been open for over a year.