Raw rubber Testing

[Aleal2]

I mold rubber, and recently we had parts of a lot of rubber that came out defective, rubber didn't bond correctly.

I'm sure only parts of the lot are defective, but we can't take a chance and make a bad product.

Is there a way to test it so we can know what part to discar and what part not.

Or a process for which this rubber can be used.

It is about 3000 lb of uncured biltrite rubber.

 

[enriqueturner]

probably your press is too hot, try to work wit 10 centigrades cooler and compensate with larger time,

if you have your press too hot, the rubber starts vulcanizing on the surface, that vulcanized rubber acts as a thermal insulator not allowing the heat to travel to the core.

 

[GrahamBennett]

In some respects Enrique is correct, in others he is wrong.

First, yes by all means try 10°C cooler temperature but use double your usual cure time.

Second, yes too hot and you will get scorch in the surface. ALL rubber, vulcanised or unvulcanised, acts as a thermal insulator slowing down heat transfer but not stopping it.