Guys

I am after some advice please.

I've done a bit of wet layup and vacuum bag CF composite ( only simple stuff ! ) but am now looking to use infusion to create a flat panel ( approx 400mm x 900mm ) between two pieces of glass ( to be used as wing end plates on a hill climb car ). The construction would be :-

Gel coat-CF-Soric-CF-Gel coat

My question is, the two pieces of glass ( top and bottom mould ) will be larger than the composite stack so how do you stop the resin  taking the "easy route " around the composite stack and not wetting out the CF etc fully ? ( assuming the resin input is one end and the vacuum the other ).

Thanks in advance.

Adrian

Hi Adrian,

It's a good question. What you need to do first is understand what it is that the resin wants to do. With the panel set up as you propose, what the resin will want to do is fill all of the low pressure 'voids' with the higher pressure resin. The means that what the resin wants to do is not make its way as quickly as possible to thr vacuum line but instead fill all of the lower pressure area between the sheets of glass meaning that it wouldn't be inclined to 'ignore' the laminate, even if it made it's way down the edges.

For the sake of slowing down the path around the outside of the laminate, I would suggest 'shimming' this area with some material of the right thickness (we use PTFE sheet for this exact purpose) but you could use anything you like that would make up the correct thickness. This will also reduce the chance fo the glass getting bowed. For obvious reasons it would be best to use something none-porous for this purpose.

Fred's suggestion of running the laminate all the way to the end also makes sense be we appreciate that this isn't always possible or cost-effective and so hence the shims.

In what's you're describing, gelcoat would be purely optional since the finish on both sheets should still be perfect without it. If it's for a race car we often don't bother with gelcoat.

I hope this helps and look forward to hearing how you get on.

Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Hi Matt

Using the PTFE foam board as a brake on each side is really clever. I know that sooner or later I will use this method.

That is what I like about forums like this. The exchange of new ideas and technics.

Thanks

Fred