Parallel profile surfboard construction frame width.

Answer to a question regarding the use of 3mm wide frames in the parallel profile surfboard construction system:3mm or 4mm is thinner than I'd use unless the frame junctions are tied with vertical struts, as it will reduce the glue contact area at the frame junctions by 80 to 90 percent compared with 10mm frames. Three millimetre frames won't provide sufficient glue contact area with the bottom panel either, unless one doubles the number of frames, but then the problem will be that even a slight 3mm 'creep' of the bottom panel during laminating will remove all the glue from the frames thus ruining the structure. With 10mm frames or 6mm frames there's sufficient margin that the panel can move a bit.People often assume that the parallel profile system can be 'improved' and of course tweaks and changes do occur all the time, but there is a reason for every aspect of our parallel profile designs, nothing is there arbitrarily. Changes shold ideally only be made once one understands the system completely, and there's a lot more to understanding it than most people suppose. It might look simple, but all the components are organically interrelated.So to sum up if you want to use 3mm frames then 'peg' the frame junctions with vertical struts, fillet the first frame panel on to the deck ( or the bottom if using a female mould) and apply a wide band of glue to the last panel to go on so that the panel can creep a bit without making the joint dry.If using dense timber and wanting to keep the mass low, the rail blocks should be beveled in cross section to conform more closely to the rail shape, the rail blocks must have at least half an inch or 12mm of contact ( across the blocks ) but that leaves some room for reduction compared with unbeveled blocks with an inch or more of contact in the middle glue joint.We are fortunate having paulownia as more often than not we increase the scantlings beyond the minimum required in order to give the boards sufficient mass, the resolute salmon 12 footer built recently is an example. Using our standard medium construction the board would have weighed 25 pounds, but this would have reduced drive and control too much compared with the original 50 pounder so we beefed the construction up to get a weight of 37 pounds.