Sluice design Options

[Davem]

I want to build a sluice box from wood materials. I read one book that used 1 1/2 high riffles (1x2) set 1 1/2" apart. BUT I see all these designs on the internet or commercially made styles where the riffles are set maybe 6" apart. If the wider riffle spacing because expanded metal and carpet is used? I'm not sure what size riffles to use and how far aprt to set them? Thanks for any help.

[fenixsmom]

In river: 1/4" and if you have a finishing sluice:-20 they make classifiers down to -100 mesh (100 squares per inch). Buying a sluice will probably be best. I was corrected today at the river with Traddoer, it isn't cheaper to buy the metal and attach the pieces. He told me also that he made a box out of wood and it eventually became so waterlogged it literally broke down at the river.