I’ve cut a design into carbon fibre that I’m reinstating with clear polyester. The design is quite intricate and fine...think of it as a shallow channel about 1x2mm cross section in places, but about a meter long with branches off it etc.

To exclude Air I’m filling it from the bottom of the design with a syringe. I’ve got a silicone mould on top of it, but I’m getting a lot of seepage at the interface so a lot of excess resin that I then have to remove.

What’s the best way to seal the carbon fibre/silicone interface so that this does not happen?

You could try thinning down some petroleum jelly then brushing a very thin layer over the flange.  It seals quite well so may well be what you need.  Don't use too much or it will squeeze out where you don't want it.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Thanks Warren. What do you recommend for thinning?

While I’m on the subject, what’s the best solvent for the clear polyester (for cleaning still uncured product rather than cured)

Thanks!

Just use some meths to thin it slightly.

Cleaning brushes and resin is a job for acetone.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant