DIY Small fluid bed sluice/ 3 chambers hybrid NZ style hydraulic riffles

Astrobouncer

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Jun 21, 2009
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Someone was asking me about the fluid bed I was using in one of my newer videos. I forgot to post the build on here, so here's the info on it . This video shows the latest version I just was testing some more yesterday.



It is now a prototype fluid bed with 3 chambers that uses riffles similiar to New Zealand style Hydraulic riffles only the water is supplied from side tubes instead. Previous version had 3 water tubes but the scouring action was too much and it would blow out 100 mesh gold. This version works a lot better as you can see by the gold recovered at the end of the video. Its not pretty but good enough to test with. Oh and lastly, I had to classify the material I was working because it was a lot of clay. But this thing will work great on bank run river gravels (or clay if you classify it first). As old prospectors will tell you, proper classification is always the best way to tune your equipment to the size gold you are finding.

The bottom chamber has removable window screen to keep debris out of the water pipes. Some people don't like to use window screen cause they say it plugs up. To which I say, which would you rather have plug up: Something you can easily clean on the outside of the sluice? Or a small pipe that you cant see on the inside that you have to turn the sluice upside down to clean out? Its a no brainer to me.

Here's the build before the newest changes (notice how different it is now in the top video):

This fluidized bed sluice starts at 7.25 inches wide, tapering down to about 5 inches wide at the end. It sits about 3/4 of an inch lower then my last one for use in shallower water. The trap is a little longer, at about 5 1/2 inches long but it is narrow.

I went with a little different configuration for the water pipes in the trap. I am using 3 /16 inch holes spaced 1/2 inch apart. Unlike a typical fluidized bed, the sides of the trap in this one are water pipes that point sideways and down. And the water pipe in the middle has staggered holes, 4 on each side pointing sideways also 3/16's of an inch in diameter.







Here's how high it sits compared to my last low profile fluid bed sluice.





























The removable grizzly for holding clay till it breaks up.It slides right off the top.






DSCN0577 by kensairyu, on Flickr


DSCN0576 by kensairyu, on Flickr

Here's the first version I was using:

 

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