Hi All,

I am in the process of making some moulds using EG60 as my gelcoat,
I am then laminating glass fibre reinforcement using the easy composites gp polyester resin, 
An issue have been having is the interface between the gelcoat and the reinforcement is not curing, the rest of the polyester is curing fine,

I first thought it was an issue with the temperature I was working at but I now have this under control but still have the same issue, 

I am now wondering if it could be that the epoxy gelcoat is not compatible with the polyester resin? And I have just been lucky in the past that it has not caused an issue,

I follow the instructions for the gelcoat, 2 layers, 2-3 hours wait time until it reaches b stage, then applying the reinforcement,

I would just like some input before I try a mould out of epoxy resin and carbon reinforcement,

Thanks,
Jake

+x

 

Jakeharvey - 12/29/2019 2:23:50 PM

Hi All,

I am in the process of making some moulds using EG60 as my gelcoat,
I am then laminating glass fibre reinforcement using the easy composites gp polyester resin, 
An issue have been having is the interface between the gelcoat and the reinforcement is not curing, the rest of the polyester is curing fine,

I first thought it was an issue with the temperature I was working at but I now have this under control but still have the same issue, 

I am now wondering if it could be that the epoxy gelcoat is not compatible with the polyester resin? And I have just been lucky in the past that it has not caused an issue,

I follow the instructions for the gelcoat, 2 layers, 2-3 hours wait time until it reaches b stage, then applying the reinforcement,

I would just like some input before I try a mould out of epoxy resin and carbon reinforcement,

Thanks,
Jake

There are exceptions to this rule, but in general epoxy gelcoats are not compatible with polyester resin.

Gelcoat are partially cured before you continue with the reinforcement layups. So there are only chemical bonds between the gelcoat and the reinforcement. Polyester and epoxy resin have two completely different reactive groups wich cannot bond to each other.