The matter of having layers of different density foams is one I've thought a lot about, but I can see some real potential problems. The main one is that the foams have different characteristics, and when any bending is done, the layers will behave differently..... this may or may not be a problem, one would have to try it to discover if it was. It might make senses if the foam was being laid up in the "conventional" way as strips inside a female framework, but could present some problems with getting good contact and bonding between the layers. Vacuum bagging flat pieces on a table could ensure a good bond......with the proper bonding paste, but then one is faced with the previously mentioned issues with bending.... which may be non-issues. With a single layer and infusion, no paste is needed for good adhesion.
The thinnest Divinicell by the way is over $50 per sheet.......
Infusion on the flat would seem to completely change the equation as far as foam sandwich.....
H.W.
On 07/25/2018 01:56 AM, ryanonthebeach@gmail.com [harryproa] wrote:
I am following these threads on XPS with interest. I'm sure you could write your PhD on XPS modification to get better needed properties for certain circumstances. Its an interesting topic.
What about mixing multiple materials? E.g. xps in certain locations where its properties better match requirements or mixing layers of PVC & XPS i.e. sheets of H80 over an xps core to push up certain properties but reduce cost.
It does seem to obvious to me that cheaper/lower density materials can be applied in various places to save on weight and cost, without sacrificing any critical properties that are needed locally.
I guess the first steps would be to identify what the requirements are based on scantlings? Or FEA?
Posted by: StoneTool <owly@ttc-cmc.net>
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