In this project the aim was to make the lowest possible cost kevlar or carbon fiber sheet for possible future projects. A quick Google soon confirmed that custom made carbon Kevlar or Carbon fiber panels are expensive. So this is how I made my own, with no Vacuum…
Cheap kevlar cloth
As the whole idea was to make kevlar sheet as cheap as possible, the first thing to do was to get kevlar cloth at the lowest possible cost. After trawling the internet it seemed to me that surplus or second hand bullet or stab proof vests could be the key. After buying a front panel from a bullet proof vest from eBay for £10 it was just a matter of hoping there were enough layers to make it a sensible choice. Win. 18 layers of good quality Kevlar, bargain.
Having used fibreglass many times before, my plan now was to sandwich the kevlar and epoxy layup between the glass and squeeze it until it cured. As I didn’t want the epoxy to bond to the glass a release agent was required, and as the whole idea was to make this project cheap I decided to try household alternatives to PVA and mold release wax.
Alternative mould release agents
WD-40, vaseline, oil, and automotive silicone spray. All offered up in YouTube videos as working alternatives for mold release agents for epoxy or polyester resin. I tried them all and found they either leave a strange surface finish, discolor in some way, create minute patterning or just dont work reliably. I scrapped a lot of kevlar and glass then decided it’s just not worth the effort. Buy a proper release agent.
One thing I did decide on though was to use a thin film of plastic, as I had some OHP film (overhead projector) to hand, so even if the worst does happen and the epoxy sticks fast, the film stops the glass bonding together so the kevlar or carbon fibre sheet can always be salvaged. I’m pretty sure a heat gun would remove all traces of the OHP film if the worst was to happen. This idea could also be used between flat pieces of wood with no glass as long as the surface of the wood was nice and smooth.
How to make kevlar or carbon fiber sheet
The process is pretty simple. Flat surface, OHP film, release agent, resin, cloth, repeat as necessary. Then OHP film with release agent, flat surface, then lots of weight… then wait. Apart from making sure the first layer is resin rich and the first layer of cloth is bubble free it’s all fairly easy. One tip I can give is to make sure the cloth does not build up high at the sides, if this happens the centre of the layup risks being a hollow. A hollow will not only distort the final sheet but may trap bubbles and air pockets. If you want a nice glossy finish to your kevlar or carbon fibre panels let the resin cure fully before going to the reveal.
I’m pretty happy with how the final project turned out and as I’m not building Formula 1 cars or fuel tanks for rocket ships, the final product is plenty strong and light.
The above project is aimed at adults for education and entertainment purposes only, not to replicate. Anyone doing so takes full responsibility for their own actions.