first off… to clarify some points I forgot to mention… oops
These first three boards I’m building are completely un-glassed. reasons being:
A. never worked with glass/carbon/kevlar et al.
B. currently no place to work with glass and epoxies in the amounts required, as the “nifty” workshop space I have availble quite clearly says “no-no” to epoxies (excepting small batches I mix of 4ml-30ml)
C. I am lazy to learn to glass…
D. I like the challenge
yes I’m aware that making a wooden composite board without any glass may be skirting with disaster and tears…but like I said, I like the challenge, I’m competing (again) for the “village idiot of the year” title and I like doing things contrary to common beliefs . Yes I suppose I should get my meds checked up on…
anyways… back to my original train of thought . My first board is overbuilt, which is ok for now, it should be pretty much indestructible until the swelling of the wood rips it apart or it gets bashed in the rocks… or…or
The two biggest reasons in my thinking, for the excess weight is /are (in my current boars numero uno “fastfood”)
A: central stringer overbuilt two laminates 12 x 12 pine strips
B: deck and bottom skins 8mm birch ply and 5mm birch plies , respectively
C: solid rails
So now for boards 2 and 3 I’m slowly skimming stuff in the above mentioned areas.
basicly for board three I’m thinking along the following lines:
deck and bottom have the biggest ares and thus biggest proportion of weight. So I skim the deck to 5mm but that means I need to set the ribs (or cross pieces) more frequently spaced… which adds weight …BUT I’m goinna make the ribs even lighter than before ( 5 x 6 mm pine twigs re-inforced with 0.8mm birch ply) the ribes in board # 1 were 6mm birch ply with biig holes in them.
I will have a a central stringer but that will be with the same construction as ribs mentined above. so “very light” (lighter than so far)
Inner rail in board number 1 was 2 laminated layers of birch ply :Total thickness 5mm… so for board number three I’m using the same construction as ribs and stringer (ie. 5 x 6 pine “twigs” reinforced with 0.8 OR 1.0mm birch ply) It will look alot like what LP is building (crazy hollow-carbon-kevlar-balsa) minus ofcourse the carbon-kevlar-balsa.
with all this I should be able to drop the weight of the frame to 2/3 of what it is now… I havent weighd board number 1 yet as its still un-finished I’m fervently hoping it will remain under 10 kg (some 20-22 lbs?) I 'm goinna glue the second set of 5mm pine strips onto the frame tomorrow and steam bend the rest of the strips then too.
The outer rails for board number 3 will be as Paul J has sketched above (thank you Paul) .
By no means do I expect my board to be in the same range as LP or possibly even Paul… or then maybe… I dont know.
The fact that my boards will be unglassed I will have to try to keep in mind the tendencies of wood properties in my construction designs as well… That I think Will be my biggest handicap… And challenge too…
The original idea of this thread was: IS the central stringer truly necessary in HWS boards? well maybe it is… apparently depends on many factors; how much flex ,what kind of rider etc etc…? IF the stringer is not necessary for structural integrity: then loose it, save a little weight in the process.
The idea of loosing all the ribs and using 2-3 stringers instead is a nice one as well… might try that as well.