Hi all,

I can see I'm not going to get back to this topic for a long time so I'm going to post the last formula I tested.

In general, an optimal recipe is based on characterizing exactly what you have and using as wide a range of sizes as your machine design will allow. In most cases, optimal isn't necessary. For filling bases etc. almost anything will work. For other things, a mix that goes from pea sized gravel #6 sieve to fine dust would probably be best.

My final recipe from the simulator was:
n6SiC.ag n16SiC.ag n36SiC.ag n70SiC.ag n180SiC.ag n320SiC.ag n600SiC.ag g200zeospheres-high.ag
0.242780, 0.168667, 0.112555, 0.100630, 0.110247, 0.087316, 0.022684, 0.155121,
Predicted packing density was 0.876454

Where the above are callouts for silicon carbide abrasive and 3m Zeeosphers and below are the volume percentages which are measured
by computing specific weight using the density and adding the appropriate weights of the components.

The Epoxy Used was a low viscosity epoxy: Hexion 813 and the hardener used was isophorone diamine.

For a 38gm batch of epoxy
30.3g Hexion 813
6.9g IPDA
1.0g BYK A525

Add 25.6g G200 to vessel and mix for 4 min.
Add 37.9g #600 SiC to vessel and mix 2 min
Add 44.9 #320 SiC to vessel and mix 2 min
Add 60g #70 SiC to vessel and mix 2 min
Add 62.5g #36 SiC to vessel and mix for 2min
Add 94.1g #16 SiC to vessel and mix for 2min
Add 143.6g #6 SiC to vessel and mix for 2min

Turn out into mold and vibrate.

This will be very stiff and may be easier to deal with given a little bit more epoxy.

Hope this helps.

Regards,

Cameron