I call it the double stack RPE

**X4FRNT** · Mar 24, 2021, 08:29 AM

So I took two of my retired RPE’s and made a over/under style sluice. Kind of like the Spikes Double sluice setup. Took it out this past weekend and it worked really well! With a few minor adjustments it will do exactly what I want. I’d like to be able to shovel on without classifying and keep the larger stones out of my riffles, I’ll put it through a hard test to see how it does this weekend. Thoughts?

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**N-Lionberger** · Mar 24, 2021, 12:45 PM

Never heard of an RPE sluice before. I run over under on my dredge sluice it has to waterfall off the end as the undercurrent has fully submerged riffles you have to deal with the friction of the water against the roof. If the end of the sluice dips under water the back pressure can shut down the undercurrent, also seems to help if there is some material extending off the end of the sluice so the top flow waterfalls off after the bottom sluice.

**russau** · Mar 24, 2021, 03:52 PM

I like your idea ! Now to get enough water to make it work correctly !

**RTR** · Mar 24, 2021, 04:21 PM

Throw some gold flakes in it(and a gold pan at the end to catch em and) see what happens

**wildminer** · Mar 25, 2021, 12:39 PM

Not sure what that screen is, but if material hangs up on it punch plate may be a better alternative. Nice experiment.

**X4FRNT** · Mar 26, 2021, 04:11 PM

I made a few adjustments, I made the bolts fully adjustable now so I can adjust each one to change the angle and water flow through the sluices. Also, in my first attempt I made a rookie error, the expanded metal riffles (1/8” I think, just a gutter guard from Lowe’s) were facing the wrong direction, causing the rocks to stick in them. I’m going to make a few different sized screens, that I can change in the field. 1/4” expanded metal, and 1/4” punch plate. Going out tomorrow to do a good run with the sluice, I’ll post my results!

**N-Lionberger** · Mar 26, 2021, 06:49 PM

Doesn't matter what type of screen it is small triangular rocks are going to get stuck in there.

**Goldwasher** · Mar 28, 2021, 01:00 PM

Originally Posted by N-Lionberger

Doesn't matter what type of screen it is small triangular rocks are going to get stuck in there.

especially plastic.

I tried to make abs punch one time.

total fail.

rocks are harder than plastic they dug right in and stuck.

**X4FRNT** · Mar 29, 2021, 06:07 PM

I used expanded metal 1/2”, the screen worked great this past weekend. I tested it with my pan at the end of the sluice and did about 10-12 shovels of material. Cleaned out the sluice and found a fair bit of gold for the amount I ran, I panned out the tailings and found one minuscule speck. You can see on my YouTube page, I’m quite pleased with it.

**Duckshot** · Mar 31, 2021, 02:37 PM

Originally Posted by N-Lionberger

Never heard of an RPE sluice before. I run over under on my dredge sluice it has to waterfall off the end as the undercurrent has fully submerged riffles you have to deal with the friction of the water against the roof. If the end of the sluice dips under water the back pressure can shut down the undercurrent, also seems to help if there is some material extending off the end of the sluice so the top flow waterfalls off after the bottom sluice.

Yep. Let the tail of your sluice cascade. I'm not exactly sure if it's back pressure or suction, but I catch more fines with my drop riffles if the tail is out of the stream.

**russau** · Mar 31, 2021, 05:01 PM

Originally Posted by Duckshot

Yep. Let the tail of your sluice cascade. I'm not exactly sure if it's back pressure or suction, but I catch more fines with my drop riffles if the tail is out of the stream.

I've heard this for ever ! And this is how I operated my dredge's ! I can hear "Hoser " saying this right now!!

**N-Lionberger** · Apr 01, 2021, 09:13 PM

You could make your opening to the undercurrent wider and put in a piece of sheet metal that can be slid back and forth to regulate how much goes down, I have seen some dredge undercurrents set up like that.

**X4FRNT** · Apr 07, 2021, 12:48 PM

I modified it with a bolt on the end, that way I can change the angle of the back of the sluice, making the back of the sluice more open than the front the water acts like a vacuum where the screen is. Here is the finished sluice, as you can see I added 1/2” punch plate, and changed the bolts so they sit flush on the top sluice. Works like a dream! Eric from Robinson Prospecting Equipment sent me two RPE Extensions, roughly 24” long, so I may experiment with an extended double stack RPE.

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**X4FRNT** · Apr 10, 2021, 06:53 PM

Made one all in black yesterday, looks sharp and works great. Ram it hard at the river today, did about 300 shovels of material (sticky clay and gravels). Found quite a bit of color in the first couple cleanups, took the rest of the cleanups home to process.