I have found your guide for estimating resin quantities for infusion but cant find anything on hand layup.

For a layup for model aircraft wing skin I have assumed about equal parts glass cloth / resin. This is with laying up on flat ‘transfer sheets’ and squeegeeing  off excess resin, then to be laid on a foam core later and bagged.

Would you say this was about the right ratio, with the finished skin twice the weight of the glass used?

What about carbon and Kevlar. I assume as the fabric is less dense we can expect to use more resin for weight of cloth?

 

Any guidelines in this area would be appreciated.

 

Vince

 

 

Hi Vince,

For high performance hand-layups you will typically looking at around a 50/50 fibre/resin ratio, so the layup you have suggested sounds right to me.

Kevlar is a lower density and will have a slightly different ratio in theory, however in practice we have found it to still require a 50/50 ratio, We believe this to be due to the 'springiness' caused by the crimp in the fibre acting like a sponge.

There are quite a few variables in a hand-layup so we always start out at 50/50 and then adjust this depending upon 'feel' during the layup, I realise that this sounds a little non-scientific and I suppose it is, but this is where the craftsmanship, skill, and experience of composites come into play! essentially you need to use your judgement as to whether a layup it too wet or too dry.

Paul Statham
Easy Composites / Carbon Mods - Technical