Riffles Over Expanded Over Carpet ????

[SLNugget]

I have acquired a 36" Yellowjacket stream sluice I want to add a hopper to and convert it to a highbanker. It has riffles over carpet now and I want to add raised expanded between the riffles and carpet. Will this work better or worse than the current configuration? Please I don't want to hear about Gold Hog mats. I am a fan and will probably maybe end up using them.

Also any recommendations for a hopper assy? I have looked at the RDH and S Yuba Mining products so far. I like the RDH because you do not lose any sluice length with it as happpens with the SYM. Thanks for any info.

 

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[russau]

unless you do something to trap the fine gold from slipping from between the riffels and the raised expanded, I wouldn't do this!on my 4 inch dredge, I have several riffle setups. and when I had this combo like your asking about. I brazes the expanded to the underside of the riffle so that when its all installed, you CANT see any light between them.everything you put into the sluice has to be tight or the fines will migrate underneath it and back out to the creek!

 

[SLNugget]

unless you do something to trap the fine gold from slipping from between the riffels and the raised expanded, I wouldn't do this!on my 4 inch dredge, I have several riffle setups. and when I had this combo like your asking about. I brazes the expanded to the underside of the riffle so that when its all installed, you CANT see any light between them.everything you put into the sluice has to be tight or the fines will migrate underneath it and back out to the creek!

Why would the fines going under the riffles NOT be caught in the expanded and carpet farther downstream? I cannot imagine a large guantity of fines getting through those spaces and not getting caught in the carpet under the riffles. Just my opinion.

 

[Goodyguy]

Russ has been at this a long time......longer than many have been alive, you can trust his experience or go with your opinion, the choice is yours.
Personally, I never put riffles over expanded metal for the very reason that Russ stated.

GG~

 

[Jason in Enid]

Russ has been at this a long time......longer than many have been alive, you can trust his experience or go with your opinion, the choice is yours.
Personally, I never put riffles over expanded metal for the very reason that Russ stated.

GG~

+1!

 

[SLNugget]

Russ has been at this a long time......longer than many have been alive, you can trust his experience or go with your opinion, the choice is yours.
Personally, I never put riffles over expanded metal for the very reason that Russ stated.

GG~

No disrespect was intended towards Russ. Just asking questions to have a clearer understanding of the reasons for not doing riffles over expanded. Thanks for your input.

 

[omnicron]

What he is getting at but didn't expand on is unless your riffles have a 1/2" lip on the bottom to seal the expanded metal, your going to have gaps that will allow the gold to pass under. The seal has to be tight between the carpet, expanded and riffle. Another way to think of it is take the number 7 and turn it upside down. You have to have the lip on the bottom to make the seal.

 

[Goodyguy]

"Raised" expanded is next to impossible to get a tight seal with no matter how wide the base is on the riffle. And flat expanded isn't much worth using under riffles unless it's very heavy gauge like 4 lb.

GG~

 

[Hoser John]

Just take a flashlight at night and shine it on the riffles. If you see light under your NOT sealed therefore once the gold is sucked under by the flow it's sucked right back out and out she goes. The hi volume dredge riffles-knife edged are required for a dredge(modified hungarians) and the lower flow L riffles seal over the tiny expanded metals utilized in a as typical sluice.John.

 

[Gold Rover]

You might consider placing two or three riffles at the top end of the sluice and using the expanded metal over the carpet without riffles on the bottom end.

The gold near me is small and scarce. When I run my 50 inch riffle sluice with the Hungarian riffles in place, the water flow and sluice angle are critical in keeping the fly poop from exiting downstream. Upon advice from some of the pros here, I started experimenting with different ways to catch the stuff. First off, I went to a fluid bed sluice instead of a riffle box. I also played with different set ups and water flow changes on my riffle sluice. With a slower water flow and using just the expanded metal over the carpet, it is nicely catching small gold from material screened to 1/8". It is now set up in my backyard with a kiddie pool and swamp cooler pump catching gold from some huge piles of excavated Colorado River gravel.

When I use it again in a creek, I think I'm going to go with the top riffle, bottom end expanded metal set up.

 

[Reed Lukens]

Honestly with the Jobe Yellowjacket I would change it up completely and add miners moss over the carpet to make a tight seal for the expanded to be used under the riffles. I would do this because there is room for a lot more riffles in that sluice then what they have put in at the factory. You can add expanded under it but you will have to seal it or glue it to the bottom of the riffles for the best effect. If there is a space for water to go under the riffles between the expanded, it messes up the flow. So it must seal pretty good.
YouTube changed all .wmv movies to wide screen on us late last year so please forgive the wide screen bs that they have changed many of our videos to.

 

[russau]

good video and info!~ Thanks Reed!

 

[SLNugget]

Reed and everyone thanks for the info. Appreciate it greatly.

 

[mendoAu]

Another thing to think about is that riffles create a low pressure area that causes heavies to stay put. To create that low pressure area there can't be any flow under the riffles. Hoser has a good idea with the flashljght. The best method to find out what works and what dosn't is to take a gallon of concentrates that has no gold and mix in a gram of fine/medium and course gold. Use this to test your recovery with different setups. Stick to the one that allows none to hit your catch pan. Try different angles/flow/carpet/expanded etc. Cutting your carpet or moss in half allows you to see if the gold is getting caught towards the top or bottom. A true test can only be done with a known amount of gold in and a known amount of that gold not captured. A good box (sluice or dredge) should, once captured, hold that gold in place with minimal migration all day.