6X22 Expedition Sluice Box - Vortex Dream Mat | Gold Prospecting Equipment (Green)

I noticed the bottom of these is coated with what I assume is a urethane. Shouldn't it be coated on the top side? Or was this a mold release issue in the manufacturing process?

This sluice is very lightweight and catches both large and ultra fine gold. I love using it to rerun old tailings. Because it does so well catching the fine gold. You can force feed this thing and it still runs and catches material great. The only attention to detail needed is the weight of the water will cause the center to sag a little bit and stall your flow. Just place a rock underneath the middle of the sluice and it’ll run great or make sure that the whole thing is laying on rocks or the ground or whatever you have to support it.

I shovel unclassified material straight into the sluice and it eats it up.