Hi everybody! I’m up to building a fresh new carbon fiber rudder for my racing sailing boat FD. I would like to follow exactly the instructions given in the video by easy composites about the mould making. Unfortunately it is a shame i cannot create an exact shape with foam in a first stage that i can use as a pattern for creating the mould as shown. Also i cannot use the old rudder cause i need to make another shape. I’m owner anyway of a 3d printer with which i can make the pattern, i can print in PETG, ABS and also PLA, but I don’t know if any of these materials will have strange reaction with the components of the products used for the pattern and the mould. 

If the answer is yes, how can i solve this problem still using 3d print? Or how do you suggest me casting a perfect symmetrical and wright shape for the rudder with the foam? The rudder will have anyway a foam core so i need to find how to do that In any case, but it is not as important such the external surface of the rudder to be perfectly shaped and symmetrical...

THANKS!

You can use styrene based gelcoats on 2k coatings, but ALWAYS do a test with the specific products youre using. There are hundreds of different formulas, and there are as many that arent compatible as ones that are. Find one that works and stick with it!

Thanks for helping, i’ll continuing posting some questions and advancements on other section of the forum, bye!