Can you elaborate some more on your statement that hardness doesn't change from 3 hr to 48 hrs? How much change do you define as "not much"? Also what test methods do you use?
What you've said is interesting I would like to discuss these details and of process control methods if you are willing? My email is
[email protected].
I am no longer in foam manufacturing business but i used to be a process engineer for a slab foam line and a quality engineer for a moulded foam line.
For moulded foam, there were two different specs/testing methods:
Ford - measures forces required to compress 25%, 50% and 75% (?) of the initial thickness
GM - measures thickness when compressed with fixed load.
we used Instrons as a testing equipment for above requirement.
Due to Just-in-time delievery, we could not cure moulded foam 48hrs. We have done extensive testing to prove to GM/Ford/Chryster and others that the foam hardness did not change much from 3hrs to 48hrs, provided you crush the foam correctly. (this is another story

) Once we demonstrated our findings, we tested the foam without waiting 48hrs. I don't recall "how much it changed" but we did not have to adjust the spec to account for a curing time.
Also, all moulded parts are condition in the condition room prior to testing (temp and humity).
As for a slab foam, that is another story.
i sent you an e-mail...feel free to call me
