Started building a 6" dredge

[Reed Lukens]

You don't need to make the jet oversized if your building a tri or quad jet. They don't have the issue that jet logs do..

They do still have the issue but it isn't as bad as with the other 2 but building an oversize jet will need to be done by you Leon to match your hose. A straight 6" run through the jet is by far the best and if you can make steel tubing with a 6" ID then just build a clamp that will fit over the outside of your hose and seal it to the jet. Over sized is always better. You can make some wedges to hold your box in place and the angle iron also works well with a sliding adjuster bar underneath it for the sluice angle.

 

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[principedeleon]

They do still have the issue but it isn't as bad as with the other 2 but building an oversize jet will need to be done by you Leon to match your hose. A straight 6" run through the jet is by far the best and if you can make steel tubing with a 6" ID then just build a clamp that will fit over the outside of your hose and seal it to the jet. Over sized is always better. You can make some wedges to hold your box in place and the angle iron also works well with a sliding adjuster bar underneath it for the sluice angle.

You dont have any picture of anything that works like that.. I was looking at one but not sure if this is what you mean..

 

[omnicron]

I have not done the mods yet. I really need to but my welder is no longer working.

As for the oversized jet, I guess because I'm running a 5" restrictor ring I don't have plug ups unless I suck up 2 large rocks together but any jet would have issues I think.

If you look at my build thread, you'll see the guy who designed this dredge make the comment about moving the center tower and sluice because of the reason. I didn't and wish I did then...

 

[principedeleon]

I have not done the mods yet. I really need to but my welder is no longer working. As for the oversized jet, I guess because I'm running a 5" restrictor ring I don't have plug ups unless I suck up 2 large rocks together but any jet would have issues I think. If you look at my build thread, you'll see the guy who designed this dredge make the comment about moving the center tower and sluice because of the reason. I didn't and wish I did then...

So wheres the problem with having the sluice start from the middle of the dredge ? The jet coming out too much ? What If you make something like some of keene dredges that stands out and hold the jet in place?

 

[omnicron]

You need to realize Keene proline sluices are attached to the frame not hanging from a cable. The drag on the jet from the water only pushes against the sluice verses the whole dredge. Also its pushing down on the jet causing the back of the dredge to sit lower in the water also pushes the sluice tail up. A standard powerjet has much less profile then a compression chamber fed jet so they are more sleek.

 

[principedeleon]

You need to realize Keene proline sluices are attached to the frame not hanging from a cable. The drag on the jet from the water only pushes against the sluice verses the whole dredge. Also its pushing down on the jet causing the back of the dredge to sit lower in the water also pushes the sluice tail up. A standard powerjet has much less profile then a compression chamber fed jet so they are more sleek.

I did a modification for the sluice wont want to twist..

 

[principedeleon]

Flare and jet almost done.
Believe this one will work better then the 4" one i built because i have about almost 3" of water coming just as much as im putting in..each jet measures about almost 2"x1" with 4 3/4" holes.

The chamber measures 5.5"x10". My flare came out about 14 3/4 inch wide .

 

[omnicron]

P, you bringing in a area of 3" and your taking out almost 3"? Sorry dude, I think your going to be screwed again. You need to build pressure, you need to find that sweet spot for flow...they have to work together. Like my 6" "Omnijet" I have almost a 50% reduction between the supply and the venturi tubes. If you look at any jet log, you'll see about a 50% reduction.

 

[Timberdoodle]

I think his mention of the 4 jets at 3/4" diameter each is his restriction point which is the same total area of a 1.5" jet which would be in the right volume area for a 6". Should do pretty good on pressure and flowrate. P, where did you locate the 4 jet's? On the pressure housing and use the angled feed for control of the jet spray similar to a log jet, or at the end of the feed tubes?

 

[principedeleon]

P, you bringing in a area of 3" and your taking out almost 3"? Sorry dude, I think your going to be screwed again. You need to build pressure, you need to find that sweet spot for flow...they have to work together. Like my 6" "Omnijet" I have almost a 50% reduction between the supply and the venturi tubes. If you look at any jet log, you'll see about a 50% reduction.

...

 

[principedeleon]

Omni, i have 4 jets of water entering about 3" of water and exiting 1.5" of water. The enterance of the 3" of water is at the opening at the start of the jet tube and the exit is restricted to 3/4" each one. Tim.. The water is entered freely then restricted at the end of the jet; meaning that the hoes are punched through on the 6" pipe.

 

[Timberdoodle]

P.. So the holes are drilled through the pipe all 11 degrees making the oblong? If you have problems or are going to make another one, you can make the jet orifice square and cut a square notch into the pipe. The location of the start of the square notch is calculated by the width and height between the pipe and triangle feed perpendicular to the pipe. The notch then continues to the end and make a smooth transition to the pipe and the end of the triangle. This will reduce turbulence caused by feeding a square feed into a round orifice. A square water jet may need to be made slightly larger than a round water jet because it takes a little more energy to pass the same volume, but the working effect is the same.

 

[principedeleon]

Thanks tim.. I hope i dont have to make another one i made my 4" one the same .. Square chamber and the holes round.. But i understand a bit about the squared opening it should work smoother but ill try that out maybe on a 8" one day if i make it to there.. Even though i doubt it !

 

[Reed Lukens]

You dont have any picture of anything that works like that.. I was looking at one but not sure if this is what you mean..

Yes that is what I mean, I'm back living at the river now so I'm only online once a week when I come back home for appointments

 

[Reed Lukens]

P, you bringing in a area of 3" and your taking out almost 3"? Sorry dude, I think your going to be screwed again. You need to build pressure, you need to find that sweet spot for flow...they have to work together. Like my 6" "Omnijet" I have almost a 50% reduction between the supply and the venturi tubes. If you look at any jet log, you'll see about a 50% reduction.

Exactly and because you are using only one motor to achieve what 2 would normally be doing you should look for around 1" to 1¼" of water or the 4 holes between 1/2 to 5/8.
With 1000gpm- twin jets at 1" diameter is what I use because 1" material is readily available. You will have only 500gpm give or take with a quad jet so I don't see where 4 - ¾" holes will have enough pressure where it would be perfect for a tri-jet. It may work fine but you may only be able to run a 10ft suction hose because of the lack of gpm. With one motor it's going to be a shallow water 6" anyway so a 20ft hose isn't needed but it is nice to have the length for great working area with under 10 feet of water. I'm sure that the jet will work but to what extent is the question. It looks like you have a nice shop so you could build a nice couple jet where you could adjust the flow for max pressure instead of guessing on the quad.

 

[principedeleon]

Exactly and because you are using only one motor to achieve what 2 would normally be doing you should look for around 1" to 1¼" of water or the 4 holes between 1/2 to 5/8. With 1000gpm- twin jets at 1" diameter is what I use because 1" material is readily available. You will have only 500gpm give or take with a quad jet so I don't see where 4 - ¾" holes will have enough pressure where it would be perfect for a tri-jet. It may work fine but you may only be able to run a 10ft suction hose because of the lack of gpm. With one motor it's going to be a shallow water 6" anyway so a 20ft hose isn't needed but it is nice to have the length for great working area with under 10 feet of water. I'm sure that the jet will work but to what extent is the question. It looks like you have a nice shop so you could build a nice couple jet where you could adjust the flow for max pressure instead of guessing on the quad.

Im just trying to get started with what i have i really dont want to keep spending without making some profit .. I want to get to dredge deepest about 8' .. Since where i was working at i could pick up 3 grams or more daily and i have enough lots of material to move.. I believe i could find enough to keep adding and covering the cost. I have found a matting i saw talk about in some book i dont know how good it works but it was naming it a nugget trap and i could see the gold being picked with tweezers out of this kind if matting. I was thinking maybe i could use it under the clasifier instead of slick plate.

 

[Reed Lukens]

It might pack up but it will hold the gold. I don't run slick plate under the classifier I run v-rib but what you have pictured looks good. I love the square pattern rubber, it works even better than v-rib

 

[principedeleon]

So where would it be good to place it at ? I was thinking placing this then the drop riffles but i dont know. Give me an idea.

 

[Reed Lukens]

Yea, run that first a couple feet of it anyway or as long as you can because it will hold most of your gold. Then run the drop riffles if you want afterward. I don't see a need for drop riffles because the water flow in the undercurrent is so low. Just using the expanded over carpet after the rubber mat you have will work fine down below.

 

[principedeleon]

Okay so ill eliminate the drop riffles and place the matting then expended over miners moss.

I havent really started because of its still rainning a lot. I have to give it about a week or so to find out if the dry season is going to start to kick in.
Is hard to access and come out the same day i would have to stay for weeks.