Repairing Sandblast Damage

[68c10airstream]

I water sandblasted a 1968 oem tailgate last fall and did every square inch of it and took a straight edge to it and didn't see or feel any warpage. I used sand that the lumber store stocks. I have put my hand on the backside of a panel i did years ago dry sandblasting and i got burned instantly. Through the years i have done black paint jobs so my hands are my eyes when block sanding flat panels (black shows everything). I wet sandblasted my snowblower auger housing and there was paper thin areas at the edge and i used blackjack (very aggressive ) and no warpage, so in my world i'm convinced. Good luck.