Here’s my #4 board. After three balsa compsand, it’s time to try something different.
Here’s #1 and #3. Both 6’ quads. The first is really all over the place, the third is super light, flexible and works really well for me, but is not that refined. Also had a lot of trouble with a local epoxy blushing causing all sorts of problems with delams.
So #4 is a bamboo skinned, balsa railed timberflex, compsand inspired crossover sort of.
A repeat of #3 dimension wise 6’ x 12.75" x 19.5" x 15" x 2" thick. Low rocker. #3 came in at 2kg or 4.4# when new.
Ok so did the usual thing with 1.1# eps core, but tried the flat build approach. Put in HD inserts for Probox fins (first install), leggy plug and also for vent, which I wanted to put under the skin.
I like to bag on the balsa rails. Time intensive but this is a hobby to stop me working too long. And using RR for the first time, and with the fast hardner, meant only 4 hours in the bag.
Put on balsa nose and tail blocks - made them too big which made it hard to fair them in well.
Then time to make the balsa skins. Got these from Woven Bamboo - great to deal with and have all sorts of thicknesses. These came in 8' x 4' sheets, 0.6mm thick. Three sheets rolled up into a tube about 12" in diameter and stayed there for 4 months no problems.
Woven Bamboo 7 Wakeman Street Pahiatua Tararua New Zealand
Phone: (06) 376 6448 Fax: (06) 376 6446
Tried the 3m 77 spray adhesive to put the cloth on - worked really well and gave a clean fit.
First time using RR and add F and i was really impressed with how well it wetted out. Definitely used less than the weight of the cloth and got good coverage. Managed to bag both top and bottom at the same time with the fast hardner, just used two mixes.
Tapped the skins to the core.
Bottom is 2oz inner, deck is 4oz - would be interesting to see the weight and flex with this combination
Used an EPS box to try to muffle the pump. Still too noisy!
The skins went on well with a little bleed through. I didn't put in any rail bands on the bottom, just overlapped teh skin right out to the edge.
Cut in rail bands on the deck, and so far out to the edge of the rail, leaving a flat band for the deck skin to vacuum flat on. You need to be on top of your rails to do this well.
After bagging the skins I completed the rails. Doing it this way resulted in a clean edge overlapping the balsa rails, but ended up with slightly boxy rails in places. Need more practice.
Then lammed and hotcoated as usual. 4 oz top and bottom with deck patch and fin patch. Again, found the RR very good to lam and hotcoat.
Proboxes went in ok. One tab snapped but it still sat evenly. Only had the fast hardner, so I did a half pour and used a solar shower with cold water to take any heat out, then filled the rest after about two hours.
After grinding the fin bases down and before the finish time to bake. Never done the post cure bake before. Used some sheets of EPS underfloor insulation and a 250w heat lamp. Heat was a little uneven, got to about 93* in the middle, so will try a lamp at each end next time.
Finished the board with about 5 coats of Clear floor polish, wetsand (400, 600, 800, 1000) then a polish. Simple but effective. Now just needs some waves! Will be holidaying in the Byron area in August so will report back on how it goes.
looks mean as bro i might try that boo. thanks for the thread it makes the flat board system very clear. i might like to add karl that i do one skin at a time now for a cleaner foil and i can get my nose really really thin and tail the thcikness of an fcs plug. also on im intend to recut my tables and over emphasise the last inch of nose flip. there are some new stuff i got that i can share with you if you are interested gimme a call mate
what was the blushing probs , i never have problems with ADR resins blushing. using resin research again. but its so thick i dont really use it at the moment because its so cold and the bubles piss me off
Very nice build,I have 1#eps a bamboo skinned board the deck is 2 oz,boo,4oz lam and the bottom is boo with a 4 0z lam and there is a 4 oz glass layer between 2 pieces of foam on the interior.I think without the glass between the foam and it would be right on in the flex/flex return dept.I dont think pressure dent’s are a problem with these so much as foot wells developing when the soft eps starts to break down.The deck patch sounds like the answer though.
What I found was bits of glass and the hotcoat would would go soft and powdery then lift off. Some people have told me the brand I used (not ADR) is well known for blushing.
I put the RR on an electric oil heater for about ten minutes and it flows really well.
