I’ve just completed the veneer on a second TFlex inspired board and find the veneered blank is, well, a board. It’s as stiff as. How are you guys getting any flex into that build?
Here are the specs of the 2 boards and builds: Don’t let the widths throw you off - kneeboards are my thing.
Board 1. 6’1" x 23.5 x 2 1/4 domed deck down to 1" rails (i.e. razor thin rails)
Not quite #2 EPS (something like a 1.5 or so)
2" rail cut off all round and glued on with 4oz e glass and epoxy (as close to 50/50 ratio as possible)
Top and bottom 4 oz e glass under 0.4mm close grain bamboo veneer. Minimal resin used.
5.5oz top and bottom (only cloth we had wthat was wide enough to get laps)
Board 2. As above, but 2 3/4 thick. Not yet glassed, but so stiff already I don’t know whether it’s worth it.
I know I can tune flex by removing the glass underlay and leaving veneer off the bottom deck , and I’ll do that next, but I’m wondering just how stiff your TFlex veneered blanks are before glassing?
PS What spackle do you use (Australia)? One of the problems with ligt weight EPS rails is how easy they ding, so I think spackle might be a good way to fill the rails rather than qcell prior to glassing .
on the wmd thread gl mentions he uses 2.0 oz inside,
4.0 oz outside. you use 4 in and nearto 6 outside, that in itself is
going to stiffen things up a lot.
and secondly, the thickness,
2,25 sounds good, but the second blank at 2.75, is a sure stiffener.
For example, my Coil surfboard both are 2 3/16th [ 2.19] thick only,
Berts boards are thin too. Thin and stiffer is the ticket, plus if you
lose some weight in glassing, you loose stiffness, gain more range of
movement/flex.
either take off the deck skin and loose thickness on the second, or leave bottom skin off, or just use it stiff as…
Doming the deck will add a LOT of stiffness. You could reduce the overall thickness a bit, and carry volume out towards the rails a bit more to create a thinner shape with approx the same (overall) volume and a much flatter deck. I think this is generally how the comspand guys avoid getting boards that are stiff as a door. Higher density foam rails can help to compensate for the redistribution of volume…
Are you using a higher density foam on your rails or the same density? Im a bit confused by your description.
How are you guys getting any flex into that build?
The most direct answer I can give is to use lower density core foam. I would use 1.25-1.5. Another way is to use less wood and more foam, but then it wouldnt be a tflex. A short board 2.75 thick isnt going to flex no matter the build unless you go sponge materials.
The thing about skins is…wood isnt elastic like epoxy/glass. So guys like to come here quoting Bert and say you gotta make’m thin and wide. Well yeah, but thin paddles like sh_t. Been there done all that. Foam and fiber is real nice. Coil. Wood looks best and makes people feel all warm and fuzzy good.
Lots of really good ideas here. You guys are all on the money. I make the board a bit thinner, which works well with EPS anyway. I use a 2 oz under and a 4 oz over on the decks. I use nothing under and 4 oz over on the bottom. I also shape a flatter deck. Short boards are usually under 2 inches. The board Todd Holland has been riding has a flat deck and is 1.75 thick. It’s THINNNNN. I literally couldn’t make any other construction that thin (maybe a compsand) and have it not break. And even that thin it still floats fine because the EPS is a bit better and the foam goes all the way to the rail. The blanks are pretty stiff before laminating because their close to being done. With T-Flex the outside laminate is more waterproofing than structure. Once you have the blank veneered it’s really structurally about there. That’s one of the differences between a real compsand and a T-Flex.
Do you have a layer of glass between the rails and the middle part of the blank? Wouldn’t that make it a lot stiffer than just epoxy as glue, sans glass?
(Or do you just mean that you wrapped 4oz glass around the rails?)
Thanks for the replies. It’s really good to hear from people who are doing the buiilds. We are kind of experimenting in the dark here - just a couple of us bouncing ideas off each other. Nice to hear about some of the schedules for tuning flex.
I guess I also have to reconsider my deck flows. Flatter decks would make it easier to pull the veneer into the nose kick - something I’ve struggled with on the last 2 (had to make cuts in the veneer to get it to bend right)
We have a 1 year old board with wood rails glued on with epoxy tape between. and 4 oz top and bottom - no veneer It’s pretty flexy and the deck looks like hell now but it’s still holding together, despite a deck crease. We’ve also seen epoxy glassed stringerless 2lb eps blanks and the boards came out about right stiffness wise (but they were like 3" thick glassed with a 2x6oz top deck), so we’re working from opposite ends towards something balanced.
Reducing the glassing schedule was a logical next step, and I was considering veneered top (with 2oz under after reading these posts ) and possibly nothing (no veneer) underneath given the board design (2 1/4 thick and domed board already cut). I seem to have lost much of the subtle spiral vee when I laminate the veneer on the bottom. No veneer seems a way to ratain the bottom contours.
As an aside, the kneeboards are so thick because we find we need (30%) extra volume just to paddle the darn things. There’s something about wide noses and wide short boards that makes them pigs to paddle through the break zone. Of coure I can flatten the rocker, but we have waves here you need something to push off the bottom with. I’m looking at different designs (pulled in nose, reduced width, longer intake rocker, chined bottoms up front) to make them easier to paddle so that I can knock the volume back to something resembling a standard 6’x18x2 board. I’m open to suggestions.
Dlock,
Yes I glued the rails on with glsss between. Doing this on a rocker table seems a good way to get the blank to hold it’s rocker before veneering. I suppose epoxy only would work. I do like the idea that the glassed perimeter stringers tie into the top and bottom skins to make a rectangular cross section since I believe this is what give the design its integrity. I’m not sure you get this with glue only.
I think once you start adding glass perpendicular to the plane of the board, whether down the middle or along the rail, you increase stiffness dramatically. So if you’re looking for ways to increase flex, I’d omit the glass between the rail and core for sure.
I had a 1 7/8 flat ass decked board, eps and resin research and that thing was solid as fnck. put that thing through it’s paces it is too bad the shape sucked.
I know some of you are image oriented, so here’s a pic of the board after it was glassed. Black rails are pain, not carbon (you don’t need more stiffness when you have 4+4+banboo top and bottom).
Yet to ride it (but then again, I’m yet to surf anything until my shoulder heals!)
You can also use a different flex of resin under the veneer, this will improve flex but maintain strength. Also you didn’t mention how thick the veneer is? 1/40 will be a hell of a lot flexier than 1/16. Also the kind of wood you use will have some properties to it. Bamboo is strong but really stiff. if you have 1/16 bamboo it’s going to flex like a 2x4 plank. if you have 1/40 pine or some other open grain wood your going to get a lot more flex.
For spackle I would highly recommend Red Devil One Time Filler. I’ve only worked with EPS a few times and it’s a tricky one. It doesn’t have as good as compression strength as PU in my experience hence the need for more reinforcement, fibreglass or otherwise. So listen to Greg and company!
