I built one but mine is around 4' X 3' X 3' and stands on 2 X4 legs. Add a hole and hook up your shop vac for dust control. Mine has built in gloves. (from Eastwood co)
I recommend you go with a smaller window. That large one is going to be expensive to replace as they do get etched in no time. Mine only has a 12" X 6" window. When it gets bad, slide it out and slip in a new piece.
Anything is an improvement over getting sand in every orifice of your body anytime you need to blast something!
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63 Impala*66 Chevelle SS*69 Chevelle*69 C10 Stepside*71 Cheyenne 20*72 Chevelle
Parts for sale:
http://www.angelfire.com/trek/mr409/items4sale.html