I'm looking to build my own sandblaster and see plenty of ideas online for plywood ones. I don't mind making the top out of plywood, but want the bottom part that serves to "funnel" the abrasive to the bottom via a square chute design to be metal. I want this to ensure easy drainage where the abrasive won't stick to the wood grain. However, I'm not a metal worker. I can cut some diamond shapes out of old washing machine sides with an electric shear, but I'm not sure how to join them. Then I thought of just using something like a range hood because it has the basic shape, but they aren't that deep. Does anyone have an idea for a pre-existing chute or something I can salvage and repurpose? If I could find a giant pyramid toy or some funny plastic dog house I could turn upside down, I'd even go for that.

Thanks in advance for any ideas.