Cheap & stiff carbon sheet - how to achieve

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#1

Im looking for method to produce few flat carbon sheets like 90x90 centimeters

When I used infusion I got nice surface but even though I used carbon and 4 layers of 300g glass the panel weren’t stiff , what is more it was quiet soft - holding at both ends I could make almost a tube with it.

My question is :

Whats the cheapest way to get nice carbon sheet which will be stiff. When I was laminating stuff with polyester resin I was happy about stiffness , and with carbon Im not.

I dont take soric into account.

#2

Foam or balsa core. Thicker the core, the stiffer it will be.
you didn’t say how many layers of carbon… Carbon is very flexible when in a thin laminate. Glass is also very flexible.
If you know you are going to be loading one direction (bolted one side, and other side is attached to something else), then you can use uni-directional fabric to stiffen that one loading direction.

Else, more and more layers.

#3

Im giving 1 layer of carbon just for esthetic , what i mean is when we use like 4x carbon plies we get rather flex sheet with 800grams totally , but if we use 400grams CSM and polyester we will get much stiffer material , and its much more cheaper

So where is exactly the power of carbon above polyester? I believe it starts when we get like 10 plies of carbon

#4

Also polyester isn’t as strong as epoxy.

Definitely sounds like you need a core though. You can use soric core mat pretty easily and won’t add too much thickness. If thickness is not an issue you can go for a foam, balsa or honeycomb core.

You can also add stiffeners to the back side to make a more rigid plate.

#5

Your post reminds me an old joke going around when I was a kid
" If I had ham I would make some ham and eggs , but I have no eggs "

#6

I use that quote often actually :slight_smile:

#7

What do you guys think about polyester backing added to epoxy peel ply side?

cheap & fast - stiffness for sure

#8

Polyester and epoxy don’t really play that well together.

#9

Thickness (regardless of material) greatly affects stiffness. If your carbon is only aesthetic why not use 2 csm layers for thickness and a carbon aesthetic layer all with polyester resin.

As above introduction of a core will increase stiffness lots.

#10

Since you are already infusing then just add a core of soric or foam with a glass backside and infuse as you were??