Talk Composites - The Forum for Advanced Composites

Cloth - resin ratio

http://www.talkcomposites.com/Topic2587.aspx

By Vince - 8/10/2012 12:21:42 AM

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

 

 
By Paul (Staff) - 8/18/2012 10:01:38 AM

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.