Sodium Silica Sand Casting Rocks!
* Fewer Failures
* Faster Results
* Bigger Castings
* Less Equipment
* No storage

Resources:
Foundry Practices http://movingimage.nls.uk/film/1529
Building a Furnace    • DIY Metal Casting Furnace - Part 1  
More Furnaces: http://svseeker.com/casting_furnaces.htm
Building a Burner    • DIY Metal Casting Propane & Waste Oil...  
Casting Propellers: http://svseeker.com/casting_boat_prop...

OMG! Wear a respirator! Glass Micro Balloons will Destroy Your Lungs" and Other Myths:
"In the case of GMBs the increased persistence, when sequestered in the epithelium did not result in any additional reaction to the particles. This is consistent with the known properties of these glasses which generally show little or no tissue reaction. A survey of 46 workers exposed to GMBs also showed no evidence for an effect on lung function or on increased prevalence of respiratory
symptoms (I. P. Tarns—personal communication). Thus the retention of small numbers of GMBs for extended periods in the lung tissue is without demonstrable effect in rats or humans. The consequences for similar retention of a more reactive particle are unknown, but may be less benign." http://annhyg.oxfordjournals.org/cont...