Ski Builders Forum

I allways have a not so neat looking line between the sidewall and base/edge and the topcoat formed by the (flax) fiber. ( see picture)
Is there something wrong with my setup of is this "normal"?
How can make it look better?


I normally use 2 layers of flax uni and 45+- and carbon/kevlar reinforcement.
In a vacuum press

Thnx a bunch!

it looks uniform and relatively normal I think. The only thing I would suggest is more pressure but you are limited by your vac set up.

Flax fiber can be pretty bulky, so I would say this looks normal. A pneumatic press might be able to compress the fibers a bit and make that line narrower. If your skis ski well and don't delaminate easily, I wouldn't worry about it.

I can’t tell from the photo, but if the lower ply seems to be compressing less that the upper ply, make sure your core’s rabbet is plenty wide and not too deep. A little extra wide and a little shallow is safe. Also, if you have lower cassette alignment, make sure it isn’t ever higher than your edge.

thnx for the input.

On this pair the vaccuum dit drop at a certain moment, and I did not see it until a few hours later.
So mabey that is way it is more noticeable to me.
And yes, more pressure would probably make it thinner, I do think it is thinner on my other skis, where I had almost perfect vaccuum.

I don't use a casset, so that wont be troublesome.

But I will recheck the rabbet.

Otherwise, there was a differents in thickness underneath and above the core.
(for experimental purpose )

The ski did handle very good and there are no visual problems after 1 week of skiing.

So the flax is only lenghtwise placed UD? Then there is no structural reason to have it overlap with the edge. I suggest cutting the flax to stay between the edges and only have the carbon/kevlar 45s (the only transverse reinforcement) overlap with the edges. You will not need the rabbet anymore. If the two flax layers together are much thicker than tha T's of the edges, cut one layer to fall between the edges and let the second overlap with the edges.

Flax is a thicker material than Fiberglass and does not compress in the same way. So for 2 layers I'd say that looks normal.

Timw that was what i was thinking of doing.
But can I do this with all the layers? so non of the fabric is going over the edge?
maybe an opposite rabbet, so the sidewalls are thicker then te core it self, so there is no gap between the layers
That will maybe not give a good bond between the vds tape and core and the topsheet..

Anyways, vacuum doesnt create optimal pressure for flax. You either need to be very careful with the amount of resin you use (exactly the right amount) or you should press it with 5bar in a pneumatic press. This is what Bcomp was saying afair.

Jdline wrote: ↑Thu Feb 03, 2022 12:59 pm Timw that was what i was thinking of doing.
But can I do this with all the layers? so non of the fabric is going over the edge?
maybe an opposite rabbet, so the sidewalls are thicker then te core it self, so there is no gap between the layers
That will maybe not give a good bond between the vds tape and core and the topsheet..

I would not do it with all the layers. Keep the 45s overlapping with the edge. Otherwise you have no transverse reinforcement holding your edge. Ptex is not strong, transverse strength of your woodcore is low as well.