I've been doing quite a bit of outdoor sandblasting of large car parst with an old Tip portable blaster that has a 90-lb. pot, and using 30-mesh sand as the abrasive medium. My compressor has 10 hp. and is connected to an 80-gallon air tank.
With the 30-mesh, I find that a 1/8" blasting tip is the smallest I can use without clogging (I'm using a small tip so I can blast longer before having to wait for the compressor to re-charge the tank).
I've found that if I regulate the pressure down to 80 lbs. at the blasting pot, it still works well, I can blast longer than by leaving it unregulated (around 120 lbs.) and I don't get that big, wasteful blast of air containing no sand when I first open the blast valve, the way I do when I run it unregulated at the pot.
I've assembled an HF blast cabinet but haven't used it yet because I want to "do the mods" first and haven't got a round tuit yet. It will be nice to start using the cabinet for blasting smaller stuff because I will then be able to re-use the media.
So please tell me your experiences and words of wisdom about sandblasting!