Test Run of $4 Fluid Bed Sluice

[shinjak]

I was amazed when I saw astrobouncer's fluid bed sluice videos. He made it look so simple, I knew I could build one! I have been scrounging wood for a year now to support another hobby of mine (beekeeping), so I had plenty of scrap wood laying around. I was also able to find some 1" pvc pipe and 1/4" hardware cloth for the grizzly. The only thing I had to buy was the pvc end caps ($1 a piece) and a tube of waterproof caulk. I finally got it finished Friday night and was itching to take it out today but had to wait for the weather to clear. So around 3:30 I headed to the creek. They don't call test runs shakedowns for nothing! After realizing some embarrassing mistakes (caulk doesn't dry overnight!), I think the design was a success. I did redesign the trap using coroplast in order to be less caulk dependent.

I ran some classified material, and ended up with some black sands and garnets in the trap. So I know it's holding the heavies. It was cool to hear the material scouring the trap - instant stratification. Another thing I noticed is this thing is hungry and takes lots of water flow. I plan to spend most of the day tomorrow feeding this thing and I'm hoping for some color. This thing is not pretty, but I hope to post some pictures of it tomorrow.

For those interested, the bed is 7 1/4" at the top and narrows down to around 6 3/4" at the bottom. PVC pipe is 1" in diameter with 1/8" holes spaced 1/2" apart (making 5 or 6 holes per tube). The fluid bed is roughly 6.5"Wx5"Hx4"D. I added a bamboo skewer riffle in front of the grizzly mainly to protect the lip of the grizzly. Debated adding a low profile V mat (salvaged floor mat) above grizzly, but haven't added that yet. Seems like most people end up removing inspection mats on these sluices.

This thing was a blast to build. My next one (yep, another one) will probably use coroplast for the slick plates to make for a lighter sluice and will be lower profile. Stay tuned!

 

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[KevinInColorado]

Sounds like you are on the right track. Just stop classifying and you get more gold for the same work!

 

[GoldpannerDave]

Well, let's see those pictures of the sluice and the gold you are capturing!

 

[shinjak]

Well had more time to test the sluice yesterday. I figured out what the sluicing videos I've watched are editing out: setting the sluice up! But after that was accomplished, we had time to run two 5 gallon buckets of classified materials and around 30 shovel fulls of unclassified material. I was really impressed at how fast this box would gobble up the material! I could have gone through a 5 gallon bucket of 1/4" material in under five minutes. The 30 shovels of unclassified stuff probably took less than fifteen minutes. My son was helping me keep the slick plate cleaned off and the tailings pile clear or it would have taken longer. But I was still very impressed by its operation. Unfortunately we found lots of garnets and black sand, but no gold. But I'm not giving up on this creek yet because there are two 90° bends that I haven't worked yet, some exposed bedrock, and a nicely exposed grey clay layer in one of the banks. I will be posting some sluice pictures soon.

 

[shinjak]

Wow, I didn't realize how much damage the water had done to this box until I took pictures of it tonight. Definitely some gaps that need patching. I removed the riffle at the front edge of the grizzly which left a white mess on the slick plate. So here it is, zits and all.

Here you can see the total width is around 7.5 inches wide.

It tapers down to around six inches wide. This was probably the best feature because you could watch the material get sucked through the narrow part. Rocks coaxed past this point would suck on out the end of the sluice. The angled ends did create a momentary vortex which quickly cleaned out. Not sure what effect this would have on gold capture, but it sure was cool to watch.

Humongous gap at the end of the gold trap! Looks like it needs some MORE screws...

Showing the size of the gold trap.

The thing I'm most dissatisfied in with is the stupid cheap caulk I used. To long to cure and not waterproof as advertised. I will run this thing again, but it definitely needs some better waterproofing. Second tip of the day (what, you missed the first one?): screw heads make great catchers of fines. Cover your screw heads!

 

[joncutt87]

try this; it's what we seal our slide seams with at work, but be warned it's sticky stuff. I recommend buying a box of gloves, and a pile of trash rags.

 

[shinjak]

Thanks neighbor! I'm hoping our local wal mart has that or something similar? I had an idea last night about making the trap one solid removable unit. That would make clean up so much easier. Anybody ever tried to weld coroplast?

 

[joncutt87]

Lowes carries the caulk, and if memory serves correct 3m makes a high temp hot glue stick specifically for coroplast

 

[joncutt87]

Corrugated plastic glue test, Coroplast is hard to glue check that out.

 

[russau]

Very good link! thanks!

 

[joncutt87]

If you were really wanting a plastic sluice, and didn't have coroplast laying around, pvc is ridiculously easy to weld with a heat gun and some rod.

 

[shinjak]

Wow, if you want to waste a few hours (in a good way) google "welding coroplast". All kinds of things being made with this stuff from working boats to RC planes! Anyway, I have designed a second build using a coroplast slickplate and coroplast gold trap. It's a work in progress though, but I'll post some pics when I'm finished.

 

[joncutt87]

Sounds good, keep us updated

 

[shinjak]

Ok, so I have left y'all out of the loop a little bit on my latest build. I have actually tested it twice. The first time was a shakedown run where I found some embarrassing oversights. After fixing those I gave it another test run yesterday. I will try to post some pics of this thing in action later. Both slickplates and the fluid bed trap are made of coroplast. This thing is super light and fairly water tight. Most of the important seals were done with loctite super glue (thanks for the link joncutt) or by melting the plastic together. It looks like a drunken chihuahua cut the holes for the fluid tubes; he was promptly fired.

It was wet and nasty yesterday in Western NC, so of course I had to go to the creek to try this out. The water was up, which I don't think was a good thing for this sluice. I also think the fluid tubes may not have enough pressure on them for adequate clean out. It did catch some black sand and garnets, but there were more blondes in the trap than I'm used to seeing. I'll keep testing and tweaking, stay tuned.