Yes and no:-) I didn't get the institute to do the testing. Mostly because the ones i talked to usually "just" test concrete and their main focus is compressive testing, which isn't very usefull for my/our purpose. I ended up being assured by the videos of Stefs machine performing very well, so i ditched the "official testing" and went on with my casting...
However, i'm not done using EG and i have other projects in mind. But the next time around, i'm going to try to solve some of the issues i have had in my project: Mainly proper simulation models and proper degassing during casting. I've been thinking about doing the flex-testing(just as you) for quite some time, but haven gotten around to do it yet. But this is defently something i'll need to do before any new projects with it. I no longer think i need "official help" from a 3rd party to validate the stiffness of the EG, so i'll just to the testing myself. Peter(and you now :-) ) has posted quite a lot on this forum about this, and i like the idea of testing a known material first, like aluminium, to validate the process before testing own samples.
I've also been thinking about solving the degassing part by curing the casting under pressure. This is a whole other beast to tackle, but nonetheless something that defently will affect the stiffness and strength of the final casting. From my casting this is how a "cross-section" looks like:
I've tried degassing the mix, but it was not possible with my mix, the gas simply could not get out, even under "full" vacuum. The next step would be to try to add an additive to the mix that allows better degassing, but this might also affect the shrinkage of the casting and might not be desireable. So to minimize the airpockets i would like to try to cure it under e.g. 10bar of pressure to effectively shrink the "bubbles" to 1/10 of their normal size. This doesn't remove the air, but my hope was that it would minimize the effect of the trapped air. However, this does come with its own set of problems(and dangers!) but it might be a way...
/Thomas