If you have the time, you can make your own cabinet out of plywood . There are plans on the web , just do a GOOGLE .
here's one
http://jetbeetle.com/JB_body_sandblaster.htm
and
http://www.autodidactics.com/sand.htm
I wouldn't use plain sand as a media, far better to buy some of the proper stuff , there are so many types . Maybe worth asking your local blaster what he uses and where to buy it . Some of the media types are coarse, which means a rough finish, lots of primer required to smooth it out . Baking soda is great for carbies
http://www.aircooledtech.com/tools-o.../soda_blaster/
The cabinet method is by far the best way to go.
I've been told its possible to convert a normal 6 cy. auto engine to a compressor .... run it on 4 cyls. and make up a manifold for the other 2 cyls to compress the air ?
I've also thought of making up a battery of 4 stainless steel LPG auto gas tanks into a receiver ... the more air you have the better .... there are many out of date tanks around for free . If you locate them away from your shed and wrap chains around them .. if one blows it won't fly off like a missile .. even bury them in the ground ! The danger is more from flying tanks rather than shrapnel . Use a long hose to your cabinet
I'vetried the outdoor blasting very noisy and messy ..don't bother .
Mike