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~
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.
