Miniature Coin Dredge Questions

[Ocaliman]

First, let me say "Hello" to all of you out there. I am mainly a coin and jewelry hunter, since I live down in Florida (Not any raw gold here, unfortunately). Years ago, I saw an ad in one of the treasure magazines for a small coin dredge/suction device built from a weed trimmer motor, with a catch basket for coins and jewelry on the back end, but have been unable to find it anywhere. I would like to build something similar that would be compact, lightweight and not too noisy.

I know that Keene has a small coin dredge with a basket underneath to catch the finds, but, like most detectorists/prospectors, I am a bit of a tinkerer, and would like to build something myself. I have several weed trimmers in my garage, so that part is taken care of. What I need is a small pump that will mate up to the motor. I also need to figure out if it is possible to build a powerjet out of PVC or something that will not set the detector off if the coil and the nozzle are in the hole at the same time. Also, how far from the working end of the nozzle should the powerjet be? I would also like the capability of using the throttle trigger mounted to a handle, since I don't need a constant fast flow of water (only when I hit the target, would I need to throttle up until the target leaves the hole and makes it into the collection area, and then can be backed down to idle to conserve fuel).

Since you guys and gals have forgotten more about dredges than I will ever know, I would love any and all input into this project that I can get (parts, pumps, construction, etc.).

GL & HH

 

Amazon Forum Fav 👍

A History of Mining on the Kenai Peninsula, Alaska - Grab it through Amazon!

[Skrimpy]

First, let me say "Hello" to all of you out there. I am mainly a coin and jewelry hunter, since I live down in Florida (Not any raw gold here, unfortunately). Years ago, I saw an ad in one of the treasure magazines for a small coin dredge/suction device built from a weed trimmer motor, with a catch basket for coins and jewelry on the back end, but have been unable to find it anywhere. I would like to build something similar that would be compact, lightweight and not too noisy.

I know that Keene has a small coin dredge with a basket underneath to catch the finds, but, like most detectorists/prospectors, I am a bit of a tinkerer, and would like to build something myself. I have several weed trimmers in my garage, so that part is taken care of. What I need is a small pump that will mate up to the motor. I also need to figure out if it is possible to build a powerjet out of PVC or something that will not set the detector off if the coil and the nozzle are in the hole at the same time. Also, how far from the working end of the nozzle should the powerjet be? I would also like the capability of using the throttle trigger mounted to a handle, since I don't need a constant fast flow of water (only when I hit the target, would I need to throttle up until the target leaves the hole and makes it into the collection area, and then can be backed down to idle to conserve fuel).

Since you guys and gals have forgotten more about dredges than I will ever know, I would love any and all input into this project that I can get (parts, pumps, construction, etc.).

GL & HH

i am very interested in this type of set up. looking to have a small light set up powered by a two cycle engine or so to work through the sand and gravel quick. Also wondering about having the moved material pass by a detector as it comes out of the dirt so I know when I need to start looking for coins in the material.

 

[aarthrj3811]

Having run all different size's of Dredges the problem I see is.....Your head has to be under water to operate a Dredge. Any Dredge under 4 inches will not move a lot of material. Before you get to far in your projects download a Keene Catalog and check how much material they will move per hour. Divide this number by about 1/2. You need to remember that to operate a Dredge one hand will control the nozzle to keep the flow of solids to water ratio right. It takes another hand to toss all those Rocks that will not fit in the nozzle....And I will tell you there is a lot of rocks to toss...Art

 

[Skrimpy]

Having run all different size's of Dredges the problem I see is.....Your head has to be under water to operate a Dredge. Any Dredge under 4 inches will not move a lot of material. Before you get to far in your projects download a Keene Catalog and check how much material they will move per hour. Divide this number by about 1/2. You need to remember that to operate a Dredge one hand will control the nozzle to keep the flow of solids to water ratio right. It takes another hand to toss all those Rocks that will not fit in the nozzle....And I will tell you there is a lot of rocks to toss...Art

The place we are looking to dredge is sand, silt, and gravel. No rocks to move that can't be handled with a quick flick of the wrist. Most of the rocks are smaller than 1/2" d. On top of this we weren't looking to spend more than a 50-100 bucks because we aren't looking for high value stuff like nuggets. It's an old swimming hole where the bottom was bulldozed over the top of a dam to keep the hole deep for a paper mill below. We are just trying to find out if this was a high traffic swimming hole with a lot of goodies dropped. I can't justify the 2-3K prices for a dredge.

 

[Urban Prospector]

I'm mating a water pump from an old dishwasher to a weed eater motor myself.Have no idea at this point if it will push enough GPM to lift and move coins and nuggets but putting it together and testing it seems easier the figuring it out on paper and still only having a theory.

On the dry vac front I put a hose on the exhaust and use it like a blower to remove the light dust and organic matter.When it starts getting to the good stuff I'll continue to use the blower to help push the stuff into the suction hose.Point the two hoses at each other with the work area in between.I sometimes hold the blow hose with my foot so I car dig at the crack with screwdrivers or whatever seems appropriate.Couldn't see letting all that exhaust air pressure go to waste and most vacs are configured were you can take off a diffuser and plug in a hose with ease.Give it a try, works great.

Been thinking the same concept would work with water too kind of like a mini hydraulic monitor feeding a suction dredge.