Step 5: Making the Riffles

My biggest challenge on this build was making the riffles for the sluice out of steel angle stock. I am an old carpenter. I can make anything out of wood. Metalworking though is more of a challenge for me. So I hesitated for a while before taking the plunge and using steel. But I decided it was high time I learned how to weld anyway. So I bought some 1/2 x 1/2 angle stock and some 1/2 x 1/8 flat stock. My intent was to use the flat stock as rails on either side of the sluice and weld the angle stock between them to make riffles. The entire steel riffle assembly could then be lifted out of the sluice during cleanups.

I settled on 6 riffles, 4 inches apart and starting 4 inches from the bottom end of the sluice. I cut up the steel pieces without too much difficulty, even though I only had a hacksaw for the job. I don't have a lot of metal working tools.

I built a short section of sluice out of scrap lumber to serve as a jig for welding the pieces together. I used a borrowed welder to weld the pieces together. My welds are ugly (I need more practice) but they seem strong enough. I also welded on two angled pieces in the middle of the riffle assembly to serve as anchor points for holding it in the sluice.  Not bad for a welding newbie.

The third photo shows the nearly finished riffle assembly, looking like a mini ladder. I still needed to trim the top hold-down ear back a little.

After early tests with the sluice, I found I needed to weld on another flat piece at the top end of the riffle assembly (4th photo) to hold down the mesh and ribbed matting that would go under the riffles. More about those later.

The last photo below shows how the riffle tray is held in the sluice. There are two right-angle "ears" welded onto the center of the riffle tray. They have passage holes drilled in them to fit over hanger bolts in the side walls of the sluice. Wing-nuts hold them in place. It's a good system. The only challenge is not losing the wing-nuts when disassembling the sluice for cleanups.
One solution to the wear at the seams would be to create a single drop in assembly with your mats and all. Or design an inner mat that can overlap the sides and prevent wear. You could even use plastic gutters and fuse plastic riffles to the inside. A lot of ways to do the same thing. I've been looking into doing a DIY under-riffle sluice just to experiment.
<p>Looks good. I like the cradle. We do something similar, but much simpler, on the beach in Nome. One thing I might add is a second bucket inside the big tub to catch the water coming out the bottom of the box. This catches processed material and keeps it out of the intake of the pump. </p>
i understand the mechanics of everything here, only question is the riffles, what way is the best for them to be angled, towards the spray bar? towards the drop off or straight up and down? i cant figure that part out, otherwise great instructable, ill make sure to post my process when i build my trommel and hand pump mods
Is there an ideal angle that the box should be at for gold recovery? <br>
<p>The incline is as the Book says 1&quot; for every 3 ' of Length of box. My self I like to run my box as slow as it will run and still move the raw material through the box. I find that if you are in area that is producing gold in the dust to pinhead size classifying down to 1/4 inch is best just check your classifier once in a while to make sure that you are not passing up any bigger gold. It will make running your slice flatter easier if you are running and would rather run a bit bigger then a 1/2 inch classifier would do the job and if there is gold bigger than a 1/2 inch call me and I will help you to classify the material ... no really 1/2 inch is about as big as many should need here in South Dakota I use either 1/2 or 1/4 and have pretty good return. 1/4 is 4 mesh screen and 1/2 is 2 mesh so how ever many holes makes the mesh to the inch.</p>
<p>The making of a sluice is kind of like anything else it is best if you first learn to pan. The pan is the most important part of gold prospecting it may not get you the most but it will help you to understand the stratifying of the material the heavy's at the bottom these being the Black Sands and then the iron materials with a few other things including gem stones anything with a high SG. After you have learned how to separate the material in your material then you will be ready to build your own Sluice .... and this is one of the better builds I have seen in wood as long as when you build a wooden sluice you make it water tight because anywhere there is a leak there is loss of material and the Gold likes to escape your box through these leaks. New Alum Sluice Boxes with the flairs and I have not see one yet that does not have some leaks between the flair and box these have to be sealed with silicon so those with wooden boxes make sure that they are tight and sealed and that after the first few uses when they dry that they are still tight for as we all know wood warps and so it starts to warp and make these little leaks. I have tried to find a sealer for several boxes that I have made but after a few uses I find that the finish wears off from the sand and rocks running over it so if any body knows of a finish that holds up to the wear let me know.</p><p> Now a question as what can an cannot be used one has to understand that through the years many people have used many different things in the days of the bible it was the Golden Fleece and this was a Sheep Skin in which of that time was layed in a stream and the gold laden material was then poured over it then in the 1849 it was a board lined sluice with rocks or timber layed in the bottom or an extra layer with holes drilled in it to catch all or at least of the gold bearing material so I would say that if you or someone you knows try it out and report how it worked here on this site or an prospecting site I am sure others will be interested .... try anything the skys the limit who knows you may be the one that hits on the new and improved way in which to do something that has been done since the days of the days of the bible and before.</p>
<p>can we use chicken net instead of riffles??</p>
<p>how much gold have you gotten so far?</p>
Thanks for these great ibles! The simplicity of construction and economical use should make us strive to emulate your ideas. I was told somewhere during govt service about the KISS principal. You have mastered it and passed it on to us! Geniuses have learned to mask their use of someones ideas. Guess I am up there near the top. Anyway, here is a tidbit, To filter or improve filtration, add a section of panty hose. Works well wet, and is cleanable and reusuable....Thanks again.
Could this be used for diamonds? I have a mine nearby but the water is scarce. I was thinking of a centrifuge powered by a shop vac, but this seems much closer to the techniques already used.
How do you keep the sand from plugging the pump and the sprayer bar? We've tried nylons over the intake and other screen filters. Best thing for us was placing the pump inside a bucket inside the tub then only pumping the water that overflowed into the bucket. Problem was the pump kept out pacing the overflow.
sorry for so many comment put also good job much better than i could ever do i suck at wood working im more of a gunsmith guy my self.
forgot to say where in cali right in the middle of gold country.
Just a tip this might not work in all cases. Me and my dad are pretty in to this we found that if you use the black pad like you used in the first 1ft and miners moss in the first 6.in on top of the black mat, and just regular box carpet on the rest that we got a bout a 1/8 of an ounce more per cubic yard. We use a 4.in drege when we can and when we cant a 6 ft. long high banker with 4 hp pump.
cool man just woundering how munch gold you have found and what do you do with it after you find it ? do you melt it down in to gold bar's ? thank's for the project
many of the desert placers contain gold in a range from fourty mesh to sub micron range. when using a dry shaker you can consentrate these smaller particles but the fines can float off as soon as they are wetted on their surfaces. <br>Alot dry placers will run .o3 oz per ton and a two inch dredge pump can handle half ton of slurry and pump it to a long tom sluice box. with a tweny fie dollar jump in price of gold to 1250 per oz a lot more people will be trying to get few particles just remember it takes millions of those fourty mesh particles to make and ounce. ande under a two hundred power microscope they look like real nuggets. fun to get them on glass slide and magnify them so you can dream about the gold machine that make you rich.
Have you thought of building a tray and frame out of something lighter then wood?
This is very good!&nbsp; I think most readers will think this is a humorous hobby, but it is very serious.&nbsp; There is still plenty of gold being mined by hobbiests in California.&nbsp; Recirculating the water is a great advantage for the dry areas to the south.&nbsp; Who knows?&nbsp; There is proabably untapped gold in the dry rivers and streams that only get filled during major storms.&nbsp; This would allow people access to it.&nbsp;<br>
There is no doubt that heavy rains and even a bit of flooding bring gold into streams. People in the hobby look forward to some severe rains now and then as it quickly translates to gold in their collections. And finding ancient stream beds that are no longer streams can be a great source of serious finds as well.