I am renovating a 28' GRP (foam sandwich) trimaran.  I would like to use the angle section and square tube to construct 'floor joists' on which the cabin floor sits.  There are two areas that I am looking to cover: 800mm x 600mm and 1200mm x 600mm.  I plan to glue the angle to the GRP and then sit (glue) the square tube on the angle.  The cabin floor is 8mm polyethylene honeycomb (Correx).

Hi Mike,

I would probably suggest our PT326 Polyurethane Structural Adhesive - it will bond very well the the epoxy of the carbon fibre sections (the angle and the pulltrusion) and also to the GRP. Follow the usual precautions which would be to key all bonding surfaces heavily with something like a 120 grit paper and ensure they're all free from dirt, grease, moisture and loose material and then you should be fine. I have no doubt that the adhesive will bond incredibly well.

With that said, most of the other adhesives from our range of 2-part structurals would also do a very good job of this bond, it's just that given the choice a polyurethane adhesive would just edge ahead of an epoxy when bonding plastic to plastic (which is what GRP to carbon fibre is).

Other than the adhesive advice, the procject sounds good; I'm sure you'll be able to create a strong, lightweight floor support structure using the materials you mentioned. I guess you're thinking of our largest 20mm Carbon Fibre Box Section? - One thing to be aware of is that you'll need to ensure that the pulltrusion is not subject to any 'crush' force - pulltrusions are not strong in crush so avoid any point loadings onto the pulltrusion from above which could crush it.

I hope this helps and wish you all the best with your project.

Best regards, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales