Hi,

I am pondering a new boat build which will, in all eventuality, comprise making the hulls (it's a catamaran), foils, beams and maybe even a mast. I am pretty impressed with the Easy-preg option for an off the mould finish, ready for paint directly - I don't want the weight penalty of a gel coat if possible. The hulls would be a Nomex sandwich and I assume that this would be OK with a 215 gsm vari-preg layer (don't want to go to the 430 or would the experts recommend a resin layer? If so, where do I get this as there is nothing on the Easy Composites site that looks like it fits the bill. I'd like to work on a single vacuum / over cure rather than doing curing the layers individually.

My second train of thought is how to incorporate UD layers in the vari-preg system. The cat's beams, foils and mast will be a UD dominated laminate, so I will need to work this out! Again, is there sufficient resin within the vari-preg backing layer to co-infuse UD layers, or again will a resin layer be required?

Got to build an oven of course, but I'd like to get the construction resolved in my head at least.

Thanks for the great tutorials.

Cheers

Andy

I did give infusion a good deal of thought - it is a process we use at work and I know well, although we inject the (polyester) resin as well as drawing it through with the vacuum. The largest parts that I am looking to make would be a maximum 6m long by 0.5m wide by 0.2m deep (i.e. half an 18' hull), so we are not talking about a huge item to lay up & it is a pretty simple laminate; so the out life of the prepreg should not be a factor.

I'd still need an oven to post cure the infused laminate, although it might be at a lower temperature, just to avoid the inevitable core block print through. The oven would still need controls, etc. so not much saving there either. I was woring on a scalable design for the oven so that I could build it in sections, say 2m at a time. I could then "practice" on some smaller parts - rudders, etc. - before working on the larger parts. This would at least give some confidence in the controllability of the oven and reduce the likelihood of scrap parts.

I could go down the route of the Gruit SE84 prepreg with the associated / compatible surfacing resin, adhesive layers, etc. This is an 80 degree C cure. Additionally, there would be no open resin mix and hence a much lower smell issue (I am looking at working in my garage in a residential area!).

Thanks for the continued contributions, all food for thought!