Talk Composites - The Forum for Advanced Composites

polyester mould/epoxy compatible gelcoat

http://www.talkcomposites.com/Topic2776.aspx

By SakerProject - 9/8/2012 6:08:05 PM

Hi,

I'm a teacher and work with teenagers and am considering building a kayak with one particular class group. I already have a mould from which one successful polyester/glass boat was pulled about two years ago. The mould is also polyester/glass with a polyester gelcoat. The mould needs some minor modifications to change aspects of the kayak design that have become apparent in the meantime. Basically, I'll need to cut six slots, remove some material and then re-glass up the mould to make it rigid again. The total area of the modifications will be 6 slots each about 1 inch by 3inches. I intend to make the new boat from resin infused epoxy with a mixture of reinforcements including carbon, diolen, glass and kevlar with soric as a core material.

I understand that a polyester mould is risky to be using with epoxy, so my first question is whether the epoxy compatible gelcoat will lessen the chances of the new component sticking to the old mould?

The second question is whether I should use other materials to modify the mould to prevent there being any fresh polyester in contact with the new component? (if so, which materials?)

Third question, what release agent should I use? (the mould has a good finish and was well prepared with release wax previously),

Thanks,

Donnacha.
By FLD - 9/18/2012 7:32:20 PM

SakerProject (16/09/2012)
It is an eight foot long fast river surf boat designed for one specific wave - think Riot Glide but much, much less rocker, about 2" at the stern. The glass version I have is very carvey and extremely loose. I know it sounds strange but then it is a strange set of requirements. I have a squirtboat myself, its an Underdawg by Murky Waters.

Construction wise, it has to be light and extremely stiff on the hull because of how flat it is and the natural tendency of flat sections to bend, part of the reason I want to go with resin-infusion is because of the use of a core. The river is deep and rock free when the wave is in, so not too concerned about impact. The deck shape is high volume and rounded so naturally strong.


Check out the double dutch and Vajda websites and see what spec they are laying up current slalom boats up as.  They are very rigid and very light so a similar lay up should serve you well.