Question for making a hand dredge

[ikesdad]

I am starting to build a hand suction dredge and have a question...
What material is used for the piston ?
I see all kinds of videos and different types of material, some even stating that it is a secret.
So, what would be best to use for a piston ?

 

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[arizau]

A regular pump cup leather is probably the best option. I got mine at a local pump repair shop or you can find them online. I modified a plumbers expandable plug to affix it in my application. It lets you adjust the seal of the cup by tightening or loosening the plug. Make sure you pin the plug in the tubing or it will probably work it's way loose after you use it for awhile. Mine did.
https://www.google.com/webhp?source...91US513&ion=1&espv=2&ie=UTF-8#q=pump leathers
https://www.google.com/webhp?source...US513&ion=1&espv=2&ie=UTF-8#q=expandable+plug

 

[ikesdad]

Pin....drilling a hole thru the threads just outside of the tightening nut ?

 

[arizau]

Kind of like a pointed set screw/s through the wall of the tube and into or through the rubber expander to keep the plug in place. The suction and tight fit of the cup against the outer wall of the pump may/will pull the plug out of the plunger tube if it is not secured in some fashion. I used a plug with a wing nut and the rubber was ridged like a thermos bottle cap I think. Check local hdwe. store like ace. I think all I had to do was get another flat washer or two to secure the cup to the plug and when it is tightened the cup splays out to make the seal. The leather expands when wet so you can pull the plunger out and adjust the wing nut for better fit.

 

[MadMarshall]

maybe it help..

 

[arizau]

Ace carries a pvc flexible spa hose that glues up with pvc glue and fittings. If I were to ever make another pump I would use this for the nozzle. Should be able to flex enough to get to some tight spots that rigid pvc will not reach.
Good luck.

 

[meMiner]

Ace carries a pvc flexible spa hose that glues up with pvc glue and fittings. If I were to ever make another pump I would use this for the nozzle. Should be able to flex enough to get to some tight spots that rigid pvc will not reach.
Good luck.

This is a great idea. I broke the nozzle off my hand dredge first full day that I used it, when the nozzle suck firm in a crack and the water action pushed the rest of the dredge downstream. I fixed it by using a rubber coupler, but flex hose would also work.

The other point about the leather in the pump cup, is to make sure you have the right size. You want it to have room to expand, but of course not so much that it is stuck firmly in place. I think mine when completely dry, needs about a half day soaking in water until it is good-to-go. I would think if the fit were tighter, that it would be impossible to pull.

 

[arizau]

This is a great idea. I broke the nozzle off my hand dredge first full day that I used it, when the nozzle suck firm in a crack and the water action pushed the rest of the dredge downstream. I fixed it by using a rubber coupler, but flex hose would also work.

The other point about the leather in the pump cup, is to make sure you have the right size. You want it to have room to expand, but of course not so much that it is stuck firmly in place. I think mine when completely dry, needs about a half day soaking in water until it is good-to-go. I would think if the fit were tighter, that it would be impossible to pull.

Yep mine gets tight when wet too. Usually get a seal in about ten minutes of soaking. That is why I like the adjustability my configuration allows. When it is tightened the cup is forced down onto the pvc plunger and splays the leather. Too tight? Back the thumbscrew off and the leather can flex back to match the shape of the pump sides.

 

[Bejay]

I have a commercially made hand suction gun. I have had it for about 25 years. The suction portion of the tube is a rubber ball pressed between two nuts with washers on a piece of threaded steel stock. The ball lasts for a very long time....as a matter of fact I have never had to replace one. But the outfit that sells the suction guns (shrimp guns) sell the ball replacements. The replacements have the threaded stock "hole" and are the right kind of rubber ball....size etc. 2 inch PVC. I can not make the tube I have for the same money I can buy the commercially made one for.....and it is designed for easy use and handling.

I could send "balls" if people interested. The whole suction gun is around $20.00 tho.

PS: If the ball to wall contact gets weak you simply tighten the lower nut/washer and squeeze it a little more!

Bejay

 

[ikesdad]

Is that one of those automotive suckers for filling differentials ?

 

[Jimmydolittle]

I've seen them made with a tennis ball like that.

I have a commercially made hand suction gun. I have had it for about 25 years. The suction portion of the tube is a rubber ball pressed between two nuts with washers on a piece of threaded steel stock. The ball lasts for a very long time....as a matter of fact I have never had to replace one. But the outfit that sells the suction guns (shrimp guns) sell the ball replacements. The replacements have the threaded stock "hole" and are the right kind of rubber ball....size etc. 2 inch PVC. I can not make the tube I have for the same money I can buy the commercially made one for.....and it is designed for easy use and handling.

I could send "balls" if people interested. The whole suction gun is around $20.00 tho.

PS: If the ball to wall contact gets weak you simply tighten the lower nut/washer and squeeze it a little more!

Bejay

 

[CA Gold Hunter]

I used a test plug from Home Depot and cut 2 pieces of leather I got from a arts and craft shop and it works really well. Don't need to adjust it and as it gets wet it swells a bit and seals any gaps.

 

[delnorter]

I also have the style Bejay spoke of. The rubber ball on the threaded rod is really neat. Basically unlimited adjustment and a very tight fit. I have had mine for years as well.

Mike

 

[KevinInColorado]

I agree leather is your best option for performance and longevity. That's also what the commercial hand pumps use (e.g. Gold-N-Sand)

 

[Jeff95531]

I have a commercially made hand suction gun. I have had it for about 25 years. The suction portion of the tube is a rubber ball pressed between two nuts with washers on a piece of threaded steel stock. The ball lasts for a very long time....as a matter of fact I have never had to replace one. But the outfit that sells the suction guns (shrimp guns) sell the ball replacements. The replacements have the threaded stock "hole" and are the right kind of rubber ball....size etc. 2 inch PVC. I can not make the tube I have for the same money I can buy the commercially made one for.....and it is designed for easy use and handling.

I could send "balls" if people interested. The whole suction gun is around $20.00 tho.

PS: If the ball to wall contact gets weak you simply tighten the lower nut/washer and squeeze it a little more!

Bejay

Got a link for the one you use Bejay? I've not seen one for $20...good price!

 

[Bejay]

Got a link for the one you use Bejay? I've not seen one for $20...good price!

I honestly don't know how anything could be better than the rubber ball. Leather will dry and crack unless treated with a oil...."ouch" not good for the gold end of things. Bi Mart Stores in Oregon sell the "shrimp guns". My secretary works for both Bi Mart and my business.....so I was able to have her send me a bunch. Last time I purchased them they were under $19.00 but that was a few years ago. I have Canadian miner friends who took some back up to the northern bush and used them way back in the remote areas.

About 30 years ago I purchased a small 2 inch backpack dredge to pack into remote, high mtn., areas of Oregon. It was a real pain...packing all the stuff and "gas". Even tho the dredge unit was a self contained back-pack itself. later I started using my shrimp gun (about 25 years ago). I could actually do as much with my pump gun as I could with the 2 inch dredge. So I sold the two inch and only use my suction gun now. There have been times I have gotten as much gold in a day with my 2 inch suction gun as I have done with my 4 inch dredge.

I honestly can not imagine anything better than the rubber ball. The unit I use has been around for at least 35 years. It is quiet and requires very little accessories. A 6 inch high sided lug/tub...a gold pan...and some crevice tools. I have set a sluice up and shot the "load" right into a sluice as well.

Best placer prospecting tool I own......along with my gold pan! ! ! !


Bejay

 

[Jeff95531]

Bejay, I looked up shrimp gun on line and found some on e-bay for 22 bucks and up.

Ghost Shrimp Pump Yabbie Pump Slurp Gun Sand Slurper Catch Your Own Fishing Bait | eBay

What a super simple piece of equipment! One to learn on and experiment with without breaking the bank. I'd seen it before but it was during my overwhelming research days. It will be next on my equipment list. Thanks!

 

[Jeff95531]

Ace carries a pvc flexible spa hose that glues up with pvc glue and fittings. If I were to ever make another pump I would use this for the nozzle. Should be able to flex enough to get to some tight spots that rigid pvc will not reach.
Good luck.

I don't just "like" this, I love it! Great ad on idea! Maybe a foot pad at the bottom too....hmmmmmmmm

 

[Oregon Viking]

I honestly don't know how anything could be better than the rubber ball. Leather will dry and crack unless treated with a oil...."ouch" not good for the gold end of things. Bi Mart Stores in Oregon sell the "shrimp guns". My secretary works for both Bi Mart and my business.....so I was able to have her send me a bunch. Last time I purchased them they were under $19.00 but that was a few years ago. I have Canadian miner friends who took some back up to the northern bush and used them way back in the remote areas.

About 30 years ago I purchased a small 2 inch backpack dredge to pack into remote, high mtn., areas of Oregon. It was a real pain...packing all the stuff and "gas". Even tho the dredge unit was a self contained back-pack itself. later I started using my shrimp gun (about 25 years ago). I could actually do as much with my pump gun as I could with the 2 inch dredge. So I sold the two inch and only use my suction gun now. There have been times I have gotten as much gold in a day with my 2 inch suction gun as I have done with my 4 inch dredge.

I honestly can not imagine anything better than the rubber ball. The unit I use has been around for at least 35 years. It is quiet and requires very little accessories. A 6 inch high sided lug/tub...a gold pan...and some crevice tools. I have set a sluice up and shot the "load" right into a sluice as well.

Best placer prospecting tool I own......along with my gold pan! ! ! !


Bejay

Bi-Mart huh? We have a new (year old) Bi-mart! So does your shrimp gun out perform a gold N sand? If it keeps up with a 2 inch dredge I'm guessing yes.

 

[delnorter]

Again, I agree with Bejay. The rubber ball system is really simple and care free. Jeff and Oregon Viking, these shrimp guns are sold at the "Coast True Value" hardware store in Crescent City. Get the basic unit and modify it as you need. Curved end, reduced tip for crevices, etc.

Mike