I see your video and my attention to move the resin with the brush, I had problems oncecured because of this, that removing the brush with some small parts of catalystremaining in the brush and distorts the proportion of mixture, perhaps in the gelcoatwhich has less catalyst you encounter this problem. I always use a plastic knife to mix,and then wait a few minutes to disappear most air bubbles ...

www.ktuning.es  

Hey thanks for your response...

Ok thanks manu, you've got a good point over there not to mix with a brush but better with a stick or something similar

Matthieu Libeert
Founder MAT2 Composites X Sports
website: www.mat2composites.com

Hi,

Thought I would share what I have. I'm a lazy guy so I had to do something which keeps work to a minimum...It cost me nothing, and it's reusable. The downside is that degassing the resin is mandatory, but hey I'm never in a hurry



 



 


    A $1000 electronic device will always protect a 10 cents fuse

Haha nice!

are you using the uni-mould system??? that is supposed to be compatible with epoxy and shouldnt have any release issues at all. The system was used in the bonnet video.

Maybe you might want to try a chemical release agent like Easy-Lease. The product video of the bonnet they used easylease and wax on top to make the mould then easy lease on the mould to make the carbon part.

I would suggest getting your mould really spotlessly clean then re-doing your release agent.  If youre using a chemical release agent, the surface should feel really slick to the finger once the release agent has been properly applied.

Thanks for your reponse Warren! the fact is that I'm kind of familiar with the technique and had some good results in the past with vinylester gelcoat on a polyester gelcoated mould

Hi Matthieu,

There should be no compatibility problems between a vinylester mould surface and our epoxy gelcoat although if you're only using mould release wax then I would hope to hear that the mould was very thoroughly cured before you used it because the styrene (partiuclarly from the polyester resin you used to reinforce the part) would still be leaching out of the gelcoat and through the gelcoat for quite a few days after making the mould. Epoxy gelcoat should behave, in release terms, just the same as an epoxy resin (i.e. a part made with no gelcoat). If you can normally release epoxy parts out of your vinylester moulds (which I would expect that you can) then this should be no different.

It would be useful to know when the mould was made (how many days/weeks/months old is it) and also whether it has undergone any kind of a post cure. Finally, does the mould 'smell' of polyester; i.e. can you still smell the styrene in it.

Regarding your use of the epoxy gelcoat, perhaps we could look closely at that for a possible explaination. How long did you leave the epoxy gelcoat to cure before you backed it up with the epoxy resin/reinforcement?
The cure problems that you've had with the gelcoat I could say with reasonable confidence are down to the thoroughness of the mixing of the gelcoat - it's a very thick substance and it is difficult to get the hardener to full disperse through the gelcoat. We have been contacted several times by people who experience curing problems with all of our epoxy gelcoat and the problem is always attributable to thoroughness of mixing).

I think some readers of this thread might think you're using our GC50 Epoxy Compatible Polyester Gelcoat but actually you're using our Clear Epoxy Gelcoat. The GC50 (seen in the bonnet making video) is much thinner and also, being a polyester gelcoat (so reacted with a catalyst, not a hardener) does not require such thorough mixing because the reaction is a chain reaction not resin/hardener pairs.

If you could post me some answers to the above points I'll see if I can identify the problem more accurately.

Best regards, Matt


Matt Statham
Easy Composites / Carbon Mods - Technical Sales