2

I’m trying to figure out the best way to make this project. I have a project that I have already cut out on my CNC machine, but each end needs to be bent upwards about 15 degrees. I don’t have a press so I’ll have to soak the wood and place it in a mold. This is something I’ve done on a smaller scale before; however, on this project I need to lay down a few layers of carbon fiber and epoxy resin.

My question is: without a press, when should I perform the bending? Can I do it the same way with all the pieces attached, or do I have to bend the wood first then try and put on the carbon fiber and resin?

I’ve never really worked with resin or carbon fiber before, so this is all new to me. Although this isn’t exactly what I’m doing, here is the best image I could find online that represents my project:

enter image description here enter image description here

I have a 3/4” paulownia wood core, and will need two layers on both top and bottom of carbon fiber (or fiberglass with a small patch of carbon fiber to strengthen the center) sealed down with TotalBoat marine epoxy resin on the top and bottom. Around the edges will be Simpakt urethane resin.

Right now I just have the basic shape cut out, but I still need to do a lot of design and throw it back on the CNC to get the final shape.

4
  • 2
    Welcome to Woodworking.SE. Without knowing a lot more details about your project, it's impossible to give anything approaching useful advice. Links to the project or item you're proposing to build, SketchUp drawings or photos of an existing piece from various sides with dimensions, a much clearer description of what you're trying to accomplish - all are things that would be very helpful.
    – MattDMo
    Aug 15 at 12:23
  • Added more information for clarity. Aug 15 at 12:43
  • 1
    You literally wouldn't be able to make the bend, not permanently, after glassing, the whole point of this process is how stiff and resistant to deformation bending it can make a substrate, in addition to sealing it off from moisture nearly completely or 100%. So it's either during (which is how it would likely be done in a lot of commercial operations) or afterwards.
    – Graphus
    Aug 15 at 18:38
  • When you steam bend wood, it always springs back a bit from the form shape. One advantage of adding the glass/CF layers in this case is that you can leave the wood minimally clamped to the form then apply the coatings while it's still in the form. Once the coatings have cured, you can remove it from the form and it won't spring back. Then you can finish applying the coatings. (Taking care, of course, to carefully blend in the edges to not have ridges.)
    – FreeMan
    Aug 18 at 14:53

1 Answer 1

8

Can I do it the same way with all the pieces attached, or do I have to bend the wood first then try and put on the carbon fiber and resin?

The latter. If you try to apply carbon fiber and resin before bending, then soaking the workpiece won't work, as the resin will prevent the moisture from reaching the wood.

Also, as you bend the wood, the surface of the wood will either compress or elongate. Fabrics like carbon fiber and fiberglass are useful largely because their incredible tensile strength lets them resist stretching; when you apply them along with resin to a surface like your workpiece, they make the surface very rigid. If you add the carbon fiber to your workpiece first, you either won't be able to bend it at all (most likely), or you'll cause the carbon fiber layer to delaminate from your workpiece.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.