Polyester resin.

[fortress]

Hello everybody,
just a quick question, does Polyester resin get more brittle the longer you leave it before turning?

Thank you one and all.

 

[Jim]

To answer the question John, No .. Well mine don't .. :wink:

 

[fortress]

Thanks for that Jim, I wasn't sure if it was an incorrectly mixed pour or I'd left it too long.

 

[Goggomobile]

John,
No not with mine ....
Sometimes the mould surfaces may be sticky but the centre should be hard ...
I find the hardner ratio can make a difference to cure time as well depending on conditions
A) make sure resin / hardner mixed thoroughly
B) resin is not past use by date - 6m I think or 12 not sure
C) hardner is not old ... looses its potency
D) moisture can change the cure time
E) temperature can affect the cure time
F) make sure you have casting resin not the layering version which never quite sets
G) storage - likes a stable place .. eg hot to cold etc can creat condensation
H) surfaces are clean ( use acetone) - I think some oils and chemicals can affect the cure

Suggest doing a small test cast in a plastic shot glass .. check how long to gel and how hot it gets and does it go totally hard ....

Randal

 

[Penpal]

Thanks Randal for your reply, food for thought.

Peter.

 

[fortress]

Thank you Randal, a list of useful considerations.

 

[wm460]

no problems with mine.