board layup 4 ply 1/16 maple by 3 sheets triaxial 19 oz fiber glass

[orange7991]

Hey so lately I have gotten into using fiber glassing my boards. I have found that I like the durability that it brings to the table and I really like having a thinner lighter board.

Currently I am laying my boards up as:

1 layer 19 oz fiber glass with west systems epoxy
2 plies 1/16 inch maple (titebond II)
1 ply1/16 inch cross grain maple (titebond II)
2 plies 1/16 inch maple (titebond II)
1 layer 19 oz fiber glass with west systems epoxy

Now I have laid up a couple boards like this (most having around a 20-28 inch wheel base) and they seems to have just a small amount of flex.

In my mind there is only one problem, I hate the look of fiber glass. It looks so ugly even though somewhat see through when I think about how I should be looking at a beautiful ply of maple.

So I know fiber glass is more effective when on the top and bottom of the board because it has tensional strength but I would like to try laying a board up like this:

1 ply 1/16 inch maple
1 layer 19 oz fiber glass with west systems epoxy
1 ply 1/16 inch maple
1 layer 19 oz fiber glass with west systems epoxy
1 ply 1/16 inch maple
1 layer 19 oz fiber glass with west systems epoxy
1 ply 1/16 inch maple

I am hoping there is someone out there who has some experience/success with putting fiberglass only in between the plies of wood. I know Original's Apex37 does this and puts fiberglass in between the plies but they also have it on top and bottom. I can only guess as what the result will be. Probably that it will be pretty durable but quite a bit more flex than a 7 ply maple or a 5 ply fiber glassed on top and bottom. The question is how much flex?

I would love any advice or feed back anyone has to offer.

[george19]

try carbon on the bottom

[orange7991]

try carbon on the bottom

Carbon is pretty cool looking, but the goal of this project for me is that the most exterior layers of the board are wood (in my case maple). I just like the more natural look.

[Rich Nelson]

Probably that it will be pretty durable but quite a bit more flex than a 7 ply maple or a 5 ply fiber glassed on top and bottom. The question is how much flex?

Sounds like you already have a pretty good idea of how it will be. Using 4 plys rather than 5 will increase flex, moving the composites in towards the neutral axis will increase flex as well. How much will the flex increase? It's hard to say, or quantify for that matter.

For one thing I can tell you that the layer of fiberglass in the middle is virtually useless. The bottom of your board is under tension (the biggest strength of fiberglass) the top is under compression (fiberglss+epoxy is pretty strong in this case too), directly in the middle of the board there are only shear stresses in which case glue will be just as effective as fiberglass. Of course this is only 100% accurate when dealing with a flat layup once concave is brought into the equation it's not quite so cut and dry.

[SandwichTech]

Like Nelson said, remove the middle triax layer because it is doing nothing. If you want to make the board stiffer without adding more plies you could split the triax into a biax and a uni layer. The uni layer would go on the outside and the biax could be hidden below one veneer. This would allow your maple to be more visible through only uni and remain stiff (it would just become softer mostly torsionally...comparable to how it is now). Another option would be to just go with your original layup and just add cosmetic veneer to the top and bottom...or birch chromaveil (dont know if that would look real enough though).

[orange7991]

Sounds like you already have a pretty good idea of how it will be. Using 4 plys rather than 5 will increase flex, moving the composites in towards the neutral axis will increase flex as well. How much will the flex increase? It's hard to say, or quantify for that matter.

For one thing I can tell you that the layer of fiberglass in the middle is virtually useless. The bottom of your board is under tension (the biggest strength of fiberglass) the top is under compression (fiberglss+epoxy is pretty strong in this case too), directly in the middle of the board there are only shear stresses in which case glue will be just as effective as fiberglass. Of course this is only 100% accurate when dealing with a flat layup once concave is brought into the equation it's not quite so cut and dry.

Thanks for your input it is very much appreciated.

So sounds like it is gonna be worth testing so I may give it a whirl while I am still out for break. Just build a new form for a board I am working on that has the specs:

Length: 39"
Width: 9.25"
WB: 26"
Concave: 5/8"
No camber or rocker

I see your point about the middle ply but I think I will stick with it just for consistency's sake and as you mention the concave will change things up a tad as well. If this doesn't work I may something in the future along the lines of

maple
glass
maple
maple
maple
glass
maple

This would add another ply of maple and separate the glass from the center a little more and might give a little more tensional strength and I will hopefully get an ideal amount of flex.