Talk Composites - The Forum for Advanced Composites

problem! resin very fragile!

http://www.talkcomposites.com/Topic1820.aspx

By Manu - 6/4/2012 10:12:59 AM

I finished making the kite board, and I have a serious problem, the resin has become very fragile, in other tests on plates, the resin is kept very flexible and very deficil reach the breaking point, the opposite of the remains of the plate that I cut the kite board, I have fear that can break a strong shock in the water. What is the problem? The board is made with carbon fiber cloth 200g/m2, 290g/m2 Diolen, soric 2mm, 450g/m2 carbon fiber, pvc foam 5mm soric 2mm, 290g/m2 Diolen lastly fiberglass 160g/m2 the resin used was the slow hardening epoxy el2, 24h curing, a post cure of 4 hours at 55 °. In tests in which the resin maintains the properties that I wish were made with fast hardener and became a postcure of 3 hours at 75/80 º. Another cause of error could be an excess of resin? the kiteboard has an excess of resin, can this make it more fragile? I fix this excess manufacturing it by infusion rather than lamination? 
By Matt (Staff) - 6/16/2012 8:54:24 AM

Hi Manu,

That's great news, I'm glad the part has cured fully now and that the results are so good.

Regarding infusing a board with an impervious core (PVC foam) if you want to co-infuse the whole thing (so the top skin and the bottom skin at the same time) then you would need to ensure that you heavily perforate the PVC foam so that the resin can get down from the top to the bottom. To do this, drill hoels through the PVC foam at about 10mm centres, making the holes about 1.5mm in size. The resin will drop down through these holes and infuse the bottom skin at the same time as the top. Never attempt to do this without the holes, the bottom will stay completely dry.

All the best, Matt