best rifle height, dead zones,

1637

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May 26, 2011
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tujunga ca
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xlt mxt gmz and now a gmt whites
Resized_20210225_124548.jpeg so i didnt like the 7/8 rifle tray with 1/4 dead zone. i like my 1/2 with no dead zones, but always looks for something better.i run a 12 volt puffer with a 13 inch wide tray, what are you thoughts on rifles height, dead zones ,angles. spacing,and anything else that would help catch more gold.
thanks brad
 

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Goodyguy

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Mar 10, 2007
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Dead zones behind the riffles are there to keep the fine gold from blowing back up into the flow.
Taller riffles will hold more material in the tray and less danger of blowing the fine gold out but creates more material to pan out.

If you are running short riffles I would definitely want to have dead spaces for the fine gold to settle into away from the puff.

Drywasher riffle angle is where it gets complicated. What you want is for the material behind the riffle to create a ramp allowing for the waterflow effect.
For instance if the riffle was at 90 degrees then the ramp is going to be too steep causing you to have to lower the end of the sluice to get a faster flow, also causing you to have to feed faster to keep up with it. Of course the correct amount of sluice drop would depend upon the height of the riffles.

I like 1/2" riffle height spaced 2-1/2" apart with a 45 degree riffle angle for running 1/2" classified material at the feed rate that I am comfortable with.
Fine tuning is dependent upon factoring in all the variables involved, so there really is no one setup that fits all situations.

The strength of the puff also has to be factored in and it varies with the diffuser cloth being used as well as the speed and volume of the bellows.
Everything has to work hand in hand to get the ultimate fine tuning.



GG~
 

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OP
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1637

1637

Bronze Member
May 26, 2011
1,766
2,407
tujunga ca
Detector(s) used
xlt mxt gmz and now a gmt whites
thanks,i will add a 1/4 inch dead zone to my 1/2 tray.i do have a speed control.
thanks brad
 

Goodyguy

Gold Member
Mar 10, 2007
6,489
6,895
Arizona
Detector(s) used
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:
All Treasure Hunting
thanks,i will add a 1/4 inch dead zone to my 1/2 tray.i do have a speed control.
thanks brad

I would recommend 1/2" of dead space for best results with 1/2" riffles.
1/4" is too small of an area and the puff, if strong enough, could still dislodge some of the fine gold.

Either way you still will have some losses with a drywasher no matter how finely tuned it is.
Just keep at it and you be able to minimize those losses.


GG~
 

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