[romihs]

Hello all...

I finally got around doing some experimenting..

I wanted to try making a mix that was dry (not pourable). I made the mix with the following ratios:
Epoxy: 8.3%
Small Aggregate: 9.8% (0.35 mm)
Medium Aggregate: 22.4% (0.8 mm)
Large Aggregate: 59.5% (2.5 mm)

I used washed and dried quartz sands.


The mixture was very grainy.



I then 'poured' the mixture into my 'mold'.


Compacted it with some wood...


Here is a side view of the compacted mixture...


I decided to embed some cap screws and a piece of Alu angle profile that has a small hole drilled though it, so that I can test the 'strength' of the E/Q...


I decided to leave what was left of the mixture after filling the two transparent 'molds', in a 'mold' uncompacted (the blue container in the following picture) to compare properties between the two.


Some of my observations so far:
1) I can understand why manufacturers use high frequencies to compact this mixture. Tapping the containers by hand had no effect on the compaction of the mixture. High frequencies should liquefy mixtures of this consistency. This is something I would like to experiment with (using some kind of a voice coil motor to achieve 4kHz vibrations).
2) The mechanical compacting method worked well, but it took quite some time to get it right. One needs to be quite gentle when tapping the surface.
3) I felt like the medium sized sand was not needed. I will make a batch using just the small and large sized sands.
4) I noticed, while mixing, that the various sized grains would combine to produce small balls of epoxy sand with a diameter of about 3mm.

That's about all from me for now. I'm waiting for the epoxy to cure, and then I will post more info. I will cure one of the finished parts further in a oven for 10 hours at 50C to compare the differences. This epoxy actually requires this, but I am curious to see how it looks without curing aswell.

Regards

Sandi