Well, the other day I had this great idea. Why not buy a portable air tank to keep on the rig to run the impact wrench? That way I can do blade changes in the field if I need to. But yesterday I was changing blades and I guess I never realized how much air the gun uses. So my question would be: How big of an air tank would I need to be able to do one good blade change (3 blades) using an air tank? Mind you, I operate my 1/2" impact at 110 psi to get the torque I want. My only concern is that I need pletty of psi left to get those blades on TIGHT! I'm thinking a 5 gallon tank ain't gonna do the trick. What about a 10 gallon. Or WOULD a 5 gallon tank work?. . .Not my area of expertise, help please! Is a portable air tank good for anything besides filling a tire (I keep a 12V compressor on the rig for flat tires)?