How to Build Your Own
Homemade Gold Dredge
Author: Chris Ralph
No question that many folks interested in prospecting for gold would love to
own a dredge. No question that dredges are very cool pieces of prospecting
equipment, but the prices for new ones are really high. You could easily spend
many thousands of dollars on such a purchase, and that is more than many
Don't forget however, that in the earliest days of dredging, there were no
manufacturers, and all small suction gold dredges were handcrafted units
made in someone's garage. There's no doubt that a good dredge can be built
by the home craftsman, and I know you can save some significant money
doing it, because I've done it myself.
For those who might ask, a suction gold dredge is basically a device which is
designed to suck gravel underwater from the bottom of a river, pull it up
through a hose and run it over a sluice box. In the sluice box, any gold which
is present becomes trapped and the lighter materials such as sand and gravel
move down and out of the sluice box and back into the river. The operator
guides to the nozzle of the hose to suck the rocks and gravel which he desires
to process off the river bottom.
A small "lawn mower" type of engine is used to pump water which creates the
suction that pulls the sand and gravel up through a hose and into the sluice
box. The gravel does not go through the pump, the suction in the hose is
actually created through a Venturi effect by pumping high pressure water
through a jet. The fast-moving water creates the suction in the jet. This way
the sand and gravel does not actually go through the pump, which would
quickly wear it down.
In addition to pumping water, the small engine also produces compressed air
for the diver to use while working underwater. In cases where the water is
shallow, the gold diver may simply use a snorkel.
Most modern dredges are made to float on the surface of the water, allowing
the operator the greatest level of flexibility to move from place to place while
working small gold deposits. Most flotation systems are made of rigid plastic
pontoons, but there are still a number of units in use that employ other
flotation systems such as truck inner tubes.
Building a dredge is a big project with a lot of plans and decisions to be made.
Take your time and think about what you really want to build. Think about
what materials you have on hand or what you could easily acquire, then build
a list of what you need to construct your dredge.
Unfortunately, a simple set of dredge plans that would work for all sizes of
suction dredges is just impossible, so I've not tried to prepare any such thing.
However, you can do it for your project. If you really sit down and think
about things, and use measurements taken from the commercial dredge
makers you can design your own set of plans for your specific dredge project.
Of course you will be building on the cheap, but you don't want to
shortchange yourself too much. You don't want your dredge to be rickety,
or to fall apart, or to fail to function. Dredges need to be functional, durable
and sturdy. The time you spend sorting through design concepts, deciding
what you will build and how you will build it will be well spent.
Think about what you want and what you need then weigh those together
with what you can afford. Do up some drawings and lists. Perhaps the best
thing I can suggest is that you study the designs of the well-known dredge
makers like Keene and Pro-line. These manufacturers have done quite a bit of
research studying their products, they have tested different options and have
developed efficient pieces of equipment that do the job well.
Check out their web sites as most have good photos of their dredges and the
individual components that make up these dredges - you can get a lot of
information from their web sites. If your local prospecting shop has a dredge
set up, take a close look and even measurements or photos if you can.
Another great possibility is to join a prospecting club whose members actively
dredge, and then go out to the claims and check out the members while they
are dredging. Take some pictures of the dredges while they're in operation.
The club members may even let you have a few minutes behind the nozzle so
that you can get a feel for the whole experience. The more general knowledge
you have about dredges before you begin your design, the better your
construction plans will be.
I have found that the junk yard / recycling yard can provide some important
pieces that you may use at low prices. I suggest that one you have good
plans for the dredge you want to build, take your purchase list and go look
through the local scrap yards - you can get stuff there a whole lot cheaper
than you would at someplace like Home Depot. You may even find a suitable
used engine there.
I suggest that once you have assembled all the pieces you need, the next
step is to put your new dredge all together and test it. I suggest that you test
it with a couple dozen pieces of small lead shot. Flatten them, and paint them
red or some other bright color. Then suck up some gravel from the nearest
gold bearing stream and put the shot in with the gravel you are processing.
Be sure to take in a good bit of gravel both before and after you've sucked
up the shot. When you clean up the sluice, count how many of the shot you
have recovered and compare that to the number you started with. You
should not lose more than one or two at the most. If you lose more than
three or four you need to adjust your dredge or make some changes to
improve it so you can be confident you are not losing gold.
For more detailed information on building a gold dredge, including
photographs of how to do it and the author's finished home crafted dredge,
check out the authors web page on building your own dredge at:
For more basic information on how to operate a gold dredge, with
photos, check out the authors web page on gold dredging at:
About the author:
Chris Ralph writes on small scale mining and prospecting for the ICMJ Mining
Journal. He has a degree in Mining Engineering from the Mackay School of
Mines in Reno. He has continued his interest in mining as an individual
prospector. His information page on prospecting for gold can be viewed at:
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