how to adust the expansion of glass and polyester resin

[niksmith]

I am presently sticking glass( of 4 mm thickness ) using polyester resin onto fibre glass of around 2mm thickness . However the problem I have is that many of the pieces seem to break after some days .
My feeling is that there is an incompatibility in the coeffecient of expansions of the two materials namely glass and resin leading to this cracking during shipment by air .
I would like to know if someone has had a similar experience and the possible solution for this problem .

Thanks in advance

 

[Compositepro]

Polyester resin has a high cure shrinkage and poor adhesive properties. The shrinkage causes high joint stress which leads to cracking. Use epoxy resin and as low a cure temperature as you can to minimize stress. The cure temperature should be higher than the highest expected service temperature, however. Also the glass surface should be treated to insure a good bond. Solvent cleaning is a minimum requirement. Silane coupling agents will improve environmental longevity tremendously.

 

[niksmith]

thanks compositepro for the advice . I have actually tried using epoxy in an other instant and found that it too detached from the glass once the temperature was either too high or too low . So I think some kind of additive needs to added to the epoxy in order to increase its elasticity or in order to reduce its hardness .