A deal has been negotiated to produce custom vermiculite as what is currently on the market is not exactly what we want.
Late last week the first sample was produced, however this was not what we asked for and was a good lesson in the properties of the material. I feel the issue is that recently I have been harping on weight and we need vermiculite closer to 300kg/m3, so the supplier got a little carried away and went lighter again to approx 200kg/m3-230kg/m3.
This was the result:
The board was too weak. Even once bonded into a composite sandwich, this will be a weak / brittle point and not acceptable.
A new sample was produced this week @ 350kg/m3 which is the perfect weight for what we need. This seemed (from what we can tell from the video) to be a good outcome. This is currently getting posted to us where we will start testing.
What we dont know yet is whether the weight (density) of the board will have a positive or negative result to the heat reduction. We will seek to answer this via testing next week. The final board may be quite different to this one (perhaps 15mm thick @ 450kg/m3???) so this is a critical part before we can proceed with the rest of the system.
Side note - unsure what the white material is on the outer. Will find out shortly and see if is an issue to bonding.