dredge build

omnicron

Bronze Member
Jun 14, 2012
1,017
409
Caldwell, Idaho
Primary Interest:
Prospecting
Sorry not enough pump. You need both high pressure and high flow rate for a dredge. Depending on your pump, clear water or trash pump, you might only be able to run a 2 to 2.5 inch hose. Trash pumps just don't create the needed pressure. The base model 4" keene dredge uses a 6.5hp engine and a p180 pump...250 gallons per minute or 15000 per hour. More specs on your pump/motor would get you a better answer btw.
 

longcut

Sr. Member
Oct 16, 2012
311
328
Misipy
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X Terra 505 and Vaquero
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I built one out of a 160 gallon/minute ,2" pump with a 5 hp briggs .................. I used a 2 inch suction and it was strong strong .......... You did not want to let it get ahold of your thigh , lol ................. I am not sure how it would react to a 4 inch suction ,,,,,,,,,,,,,,,,,, it has been a long time ago , I used a simple formula and a little trial and error to get the orfice right to create the vinturi inside the T .................... I do remember I used a 3 inch hose to supply the 2 " pump , just to make sure it had all the water the pump could use................... I took a 2 " iron T and cut it at an angle to take one side of the T off ........ I then took a 2 1/2 inch T an cut it off to fit the 2 " cut T ..... welded the cut off piece of the 2 1/2 to the 2 for a little bigger discharge hole ,,,,,,,,,,,,,,,,,,,,,,,,,, I did not answer your question , but maybe you got an idea of what you need .............. I used it to dredge swimming holes here and found tons of valuables............
 

Jason in Enid

Gold Member
Oct 10, 2009
9,593
9,229
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This is my first time building a dredge. I've picked up a 2 inch pump that runs about 9000 gallons an hour. Is that enough to run a 4 inch suction or should I go smaller? Any info would be greatly appreciated thank you

More important question, do you have any experience operating a dredge?
 

Goodyguy

Gold Member
Mar 10, 2007
6,489
6,895
Arizona
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Whites TM 808, Whites GMT, Tesoro Lobo Super Traq, Fisher Gold Bug 2, Suction Dredges, Trommels, Gold Vacs, High Bankers, Fluid bed Gold Traps, Rock Crushers, Sluices, Dry Washers, Miller Tables, Rp4
Primary Interest:
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This is my first time building a dredge. I've picked up a 2 inch pump that runs about 9000 gallons an hour. Is that enough to run a 4 inch suction or should I go smaller? Any info would be greatly appreciated thank you



Sounds about right for a 3" dredge. Not enough gpm or horse power for a 4".

GG~
 

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panningjack

Full Member
Apr 16, 2013
196
111
Nampa, Idaho
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Whites Classic 3
This is my first time building a dredge. I've picked up a 2 inch pump that runs about 9000 gallons an hour. Is that enough to run a 4 inch suction or should I go smaller? Any info would be greatly appreciated thank you

I run a 4" dredge with a 9600gph pump and it works. I use a gold divers coupler/infinity jet. However I'll still be upgrading this spring to at least 15000gph. I think you would be better off making a 3" with that pump. Or be patient and find a sweet deal on craigslist.
 

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cmatue1

Jr. Member
Jan 8, 2014
42
9
I appreciated the info. But this question is now invalid. I bought the pump used online and I went to try to start it about an hour ago and the motor is seized on it. No more buying used. And no I don't have any experience dredging, I've only been prospecting for 2 years now. I thoroughly enjoy building things and it's not gonna cost me much to build it. I've got an old river pontoon boat that I'm going to mount it to. And enough scrap aluminum sitting around to build me a sluice. Just need a good pump and motor
 

G1sammons

Bronze Member
Dec 26, 2012
1,035
256
Murfreesboro tn
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I appreciated the info. But this question is now invalid. I bought the pump used online and I went to try to start it about an hour ago and the motor is seized on it. No more buying used. And no I don't have any experience dredging, I've only been prospecting for 2 years now. I thoroughly enjoy building things and it's not gonna cost me much to build it. I've got an old river pontoon boat that I'm going to mount it to. And enough scrap aluminum sitting around to build me a sluice. Just need a good pump and motor
It's not the ability to build it that create the problem ... It's that learning To dredge has its challenges even when you have a good working dredge... There's so much to learn that you don't even realize ...And when you mix that in with building something you don't have experience running. You will end up with more money in something that doesn't work the way you want it too.. Then if you went a bought a new one... Trust me I have a huge shop with all kinds of equipment , and supplies and went down the same road your thinking about ... Well I don't have the dredge I built After a lot of wasted time and money I wished up and bought a used dredge from the beginIng .... And I'm not a dummy I bring a lot of fabrication skills to the table .. It's not that i think your not capable of building one it's that your ideas of what you want your dredge todo is gona change a lot with experience ... Your motor and pump will be the most expenceive thing on your dredge... And you can buy a used dredge in good shape for as cheap as you can buy a new engine and pump...and you rarely find eng and pumps alone used... Now with that said there's all kinds of other stuff your gona need to dredge that you commonly find with a used dredge. Such as dive equipment ...suites mask regulators air hoses air tank, dive weights .you also need a jet .suction hose presure hose. .... The list go's on and on .. And most of the time you can get all that stuff free with a used dredge. A dredge without a air system is dam near useless ....long arming sucks and it's difficult to see what your doing it also limits where you can work.. Lead to a sore back you'll end up hating it befor you give yourself a chance to get good at it ..... You'll find there's a lot of folks on here who have tried the same thing.... Amd wish they gone a different route. Most of them will tell you to built one after you learn to dredge as you will have a lot better understanding of what you need ...
 

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G1sammons

Bronze Member
Dec 26, 2012
1,035
256
Murfreesboro tn
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Look at a few simple things you missing already..
What about suction hose and nozzle and jet ...
Air system to breath while your diving .. And diving equipment mask suite regulator ..
Engine and pump..
Just add the cost of these few things you don't have.and you already cross the cost of a used dredge..
Engine and pump about 1000
Hookah compressor 300
Air hose and tank 150
Suction hose 300
Nozzle 100
Dive suite used 50
Regulator used 50


Another quick thing I noticed mounting it on a rivier pontoon what about your sluice angle ???
If you mount it on a pontoon your dredge is gona be up out of the water which means your gona need a monster pump because it takes a lot more power to pump
To a sluice up out of the water rather than one sitting in the water like most of the dredges that r manufactured today...

Not trying to beat on ya just hate to see someone make the same mistake I did ...
You can hunt craigslist and buy a good used dredge for 1500 to 2500
I see 4" keene's all the time with all the dive equipment cleanup sluice and all kinds of extra goodies for this kind of money..
 

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cmatue1

Jr. Member
Jan 8, 2014
42
9
I appreciate the info bud..... the height of the dredge out of the water didn't even cross my mind.
 

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cmatue1

Jr. Member
Jan 8, 2014
42
9
I'm in northern Utah.... the majority of our rivers and streams don't get more then just a couple feet deep.I'm trying to build it as light as possible so I can back pack it. The only dive wouldn't I'm really gonna need (at first) is just a wet suit and snorkel. I'm only gonna run a 10-15' suction line. And I'm run the pressure line out to the nozzle, to me that seems like it would give the best suction, could be wrong though.
 

russau

Gold Member
May 29, 2005
7,288
6,747
St. Louis, missouri
HMMM?? ive got more money into the dredges ive built over the years than if i just went out and bought a "used but not abused" dredge.c heck im building a new one right now, but its for a specific reason/purpose.
 

omnicron

Bronze Member
Jun 14, 2012
1,017
409
Caldwell, Idaho
Primary Interest:
Prospecting
HMMM?? ive got more money into the dredges ive built over the years than if i just went out and bought a "used but not abused" dredge.c heck im building a new one right now, but its for a specific reason/purpose.

Agree 100% I spent over $600 building a 2.5" two years ago. I wanted to do a 4" but cost was much more. Last year I bought a 2.5" and a 4" dredge with 5 wet suits, 4 regulators, and a bunch of other stuff for $1500 off craigslist. After I sold off everything I didn't want I was into the 4" for about $800.
 

Merc

Greenie
Jun 19, 2013
11
7
Primary Interest:
All Treasure Hunting
Jason hit the nail on the head. If I were you I would go out and find a local GPAA club and join it. Go out with some of the dredges and help them for a few months or a year. Help on different size dredges and get some experience before you purchase a dredge much less try to build something you have never done.

There are so many things to learn about dredging without adding in a built dredge that is not proven to catch the gold. Finding the gold is another thing I do not think you have thought about. Most dredges have a 20 ft hose and you will need every inch of it and some times you will want it to be longer depending on some things. One is the longer it i the more time the gold has time to settle to the bottom of the hose before it enters the sluice box. Which kind of sluice box are you going to use?

I highly suggest you join a local GPAA club. Then look around and see if there are any other local clubs you can join to get the experience you need before you purchase a new or used dredge. I own two Keene dredges. My first was a 3" Keene and I had been out with others several times before I purchased the 3". I thought I was ready but oh how wrong I was. Luckily I have some friends that are willing to share their years of experience and are willing to share these years of experience with me.

Do you have a place to go? Dredging is very dangerous and you need someone with you in case you get hurt. Finding someone you trust to go out with is often one of the hardest things to do unless you have a family member that is willing to go out with you.
 

Banjopicker

Jr. Member
Jan 13, 2014
28
1
Primary Interest:
All Treasure Hunting
I have a question. I just bought a used Keene 4". Now I want a swap back and forth 5 to 6". I will start building it soon. I'd like to sit the motor/pump more towards the center over the sluice and have a longer sluice box. I'm guessing since none of the manufactured dredges are made this way that its a bad idea, but why?
 

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