Material of mould for FRP boat

You may need lot of battens,perhaps every 150mm if you go too thin.If you use 12mm MDF,for example,the spacing can be greater and the shrinkage if the initial plies of glass pull is less likely to cause distortion.The hungry horse look may not be apparent until the mould is released.Unfortunate experience has taught me to avoid leaving areas where damage could occur.When catalysed resin is in use,advice not to stand in particular places may be forgotten.Strongly curved areas are more resistant to distortion.The ply ought to be the fair surface,there should be no additional work beyond filling staple or screw holes and applying a surface coating.The men I learned this stuff from built a series of plugs up to 15 metres and used no more than 300 grams of filler on any of them.

 

I used 12MM MDF as frames each 500MM in length direction then cover them by 3MM plywood.

 

Sorry for writing wrong name . 12MM MDF frames and 3MM plywood are used as plug.