Talk Composites - The Forum for Advanced Composites

Bonding 2-piece carbon fibre wing

http://www.talkcomposites.com/Topic9925.aspx

By Hanaldo - 2/27/2014 5:28:35 AM

Hey all,

Done a bit of reading, and I know this topic has been covered several times before but I couldn't find the answer I was after.

I'm currently building a rear wing blade using a 2-piece split mould. Originally I was going to do 2 layers 2x2 twill weave carbon, one layer of 3mm Soric, then one more layer of the twill weave. I was then simply going to bond the two halves together using a strong epoxy adhesive. 

However, I had a thought this morning about making some strengthening ribs to go inside the two halves, probably out of balsa wood. Then use expanding polyurethane foam to bond the two halves together. 

My thought trail was this will give me both a very high strength bond, as well as a bit more structural reinforcement. A bit more added weight sure, but it's not going to be super heavy anyway. However, I'm a little unsure as to how I would go about using the foam. I've played with the stuff before, and it has the potential to make quite the mess if I don't get the two halves together in time. Would I be better off leaving the parts untrimmed before bonding, then trim them after? To limit mess and make sure the foam doesn't spill out of the part and lock them into the mould? Or is there a better way to prevent foam leaking out?



Or should I just stick with the idea of bonding the two halves together?

Thanks for any help,
Martin.
By Hanaldo - 2/27/2014 10:34:33 PM

Thanks mate, very useful opinion!

I think I will stick to doing it as an open mould, filling the void with foam and then trimming the excess. The design of my wing does not allow for any holes for venting, so I suspect a closed mould could well lead to damage or uncured foam.