Sluice Riffles

[henryblowery]

I am thinking about making a wooden sluice and I was wandering what angle I should put the riffles at. 90 digrees? What? Thanks.
Gray

 

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[beeper]

The Hungarian riffles aid in the breaking-up process, as materials pass over them and down the box, but they serve another important function. Every riffle creates a swirling action on its lower side, which helps the gold to separate and settle out of the lighter materials. The diamond mesh in the expanded metal screen also aids in this process, which is called 'cavitation'.

If you watch carefully as the water is pouring down the sluice box; you will see a tiny whirlpool of water boiling in each diamond of the mesh. This is part of the cavitation process, and helps separate the gold from the other materials, to be captured in the fibers of the blanket on the bottom. In areas rich in coarser gold, the large one-inch mesh may be used to trap nuggets and flakes in the top box, while the finer 3/8 inch mesh in the Lower box or boxes traps the finer gold. Extremely fine flour gold requires a greater Length of box and slower moving water in order to permit it to settle. Indeed, the water of the North Saskatchewan, which contains much fine gold in its gravel, is reputed to be greasy. And we have seen flour gold there so fine that it was floating on lop of the water, in the pan, trapped, perhaps by either grease in the water, or surface tension.

see site below
www.iowagold.net/iowagolddotnet/HOWTOPAGES/how_to_build_and__run_a_sluice.htm

 

[steppegold]

Gray,
Thats good advice by Beeper...
Just to add the obvious that if you make a wooden sluice then there is a big risk of losing the good stuff through cracks in the wood that appear unnoticed due to all the wetting and banging! The solution used in Mongolia is either to make a metal sluice by welding, or to line the wooden sluice with a layer of heavy duty plastic that covers the floor of the sluice box and also dangles over the side. Then put a piece of old carpet on top, and only then add the wooden riffles. Believe me, this saves a lot of heartache! I'm posting some pictures as examples soon on:
http://bb.bbboy.net/alaskagoldforum-viewthread?forum=2&thread=304
Here already posted are pictures and dimensions of WOODEN PANS known as LOTOKS - fun to make and use.
Also, simple wooden riffles if flat bar are NOT as good as specially shaped riffes that Beeper calls 'Hungarian' that can be made out of wood of a special shape or out of angle iron.

cheers, Steppegold

 

[Gypsy Heart]

Hey Beep...Guess I wasnt the first to make my own.....hahaha....How many times have you answered this question now for us newbies

 

[Axgar]

i am a newbie .. and made my first two sluices this year... the first was more of a test of what worked and what did not.

the second was what i learned... i set my first two riffles about 12 inches appart with 45 degree angle then the last two 10 inches apart with 30 degree angle

this works for me cause i have a lot of sand and lets the water flow better. i made teh riffles inter changeable so if i go some place i can change the angle as needed.

I hope this helps and i will post some pics soon ..


Axgar

 

[beeper]

Hey Beep...Guess I wasnt the first to make my own.....hahaha....How many times have you answered this question now for us newbies

HA HA DO AS I SAY!, DON'T DO AS I DO!