Chine strips are 20mm by 10mm UHMWPE also visible in the photo. Harder to glue so the 316 SS screws stay in the boat. Below the waterline so care was needed. First drilled pilot holes and dry fit the strip. Then located the pilot holes from inside and used a 13mm drill to rout out the wood core. Filled that with putty. Would have been easier to just drill but I wanted minimal damage to the glass, which is a couple of mm thick here. The strips above on the style line just get over drilled as there is no glass to speak of there (200gsm only).
Preparing the UHMWPE. Some will say that this can’t be glued at all. Well apparently it can. The plastic has very long chain molecules that don’t strongly interact so the surface needs to be modified. First I wiped with acetone to remove dust. Then sanded with 60 grit. This was a very quick sand. Then acetone again and on to the propane torch. Kissing the surface with a quick pass of the torch (about 30cm a sec) propels reactive atoms (single oxygen and others) which are supposed to break up some of the long chains and also replace some hydrogen atoms with oxygen which can electron bond to the glue molecules. The treatments max effect is supposed to last about 15 minutes so you need to get the glue on fast afterwards. Then I screwed this into the chine like before. The screws will stay as insurance, though the glue is supposed to bond with over 2000psi to HDPE with good treatment. I have a couple of small samples: one just sanded and acetone wiped and one fully treated with wipe-sand-wipe-flame. I’ll test when fully cured. It would have been easier to go with hardwood, but I'm hoping this will be stronger and longer lasting.
