I am a professional artist but a beginner with CF. I am hoping for some advice for making large palm tree fronds from CF. (By a frond I mean casting each individual leaf not several leaves on a stalk.)

When I work in Jesmonite (water based resin substitute) I cast directly onto sheets of polypropylene that have been curved and held in position with a structure that operates as an exoskeleton (please see image of final piece if helps.)

The fronds will be approx. 300cm x 10cm. However fronds curve in two directions. I can achieve the width curve of the leaf with the polypropylene (effectively a little like casting into aplastic guttering with a u-shaped profile) but I would need to create the longer arch of the frond itself. Could be created if the piece retains some flexibility - So the cast CF piece will naturally curve. 

If people usually want a 60/40 reinforcement/resin ratio what would you recommend for a semi flexible result? (I realise I will need to do some tests but a starting point would be very useful!)

Also if possible any thoughts you may have on casting in two stages. Can I cast into the polypropylene, find the natural longer arch in the piece itself and then arrest/hold that arch somehow? Willa second layer of fibre bond to a cured section?

Could I use the CF flexible sheet to make this and then a layer of fibre and resin to arrest the second curve?

Is there any danger (fumes, melting etc) in using flexible foam strips to create the mold walls?

I realise this may seem idiosyncratic but this way of casting has informed my work for many years and I prefer to do it this way than make a conventional silicon mould. I realise it’s risky with higher fail rate.

Forgive me if I could research all these questions more thoroughly, I always find advice from experienced people invaluablel as I often use non-conventional methods.

Thank you!