Has anyone any tips for clamping ABS rails in place whilst bonding them to the core!? i`m having a nightmare - had tried tape but its extremely fiddly. Is there a better way?

Also, do you cut the rail in the shape of the rocker so that it fits better? I`ve cut mine straight and then tried to bend into the rocker but they keep springing back!

arghh - very frustrating!!

use lots of clamps with a relatively stiff batten to spread the load evenly.

or place the board between a 'rock and a hard place' then shim the gap for even clamping.

its not likely you will need to transfer outline curvature or rocker to the ABS if the cross section is any reasonable size (1/2" square or less)

most likely you are having issues with the bond strength because ABS is similar to other olefins.
epoxy is probably required for the adhesive, as well.
do a google search on "flame treating ABS" which will improve bond strength.

IMO
wrapping the rails with top and bottom laminating cloth seems a lot more reliable.
so you can always use that as your backup plan.

regards,
-bill

I put my core to flat wood base, put some bricks on the midle of core, and then use nails and hummer- go all the way around rails... connections can't be done on tips...