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PUFFER QUESTION


OldSalt

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I was experimenting with a little puffer drywasher yesterday. I noticed that this drywasher was loosing gold, so I screened everything down to a very small size and ran everything of that size together and it didn't loose any gold. I then ran larger material, which was all of the same size and the gold rolled right to the last riffle and eventually out of the tray.

Any ideas as to why this is? Does the angle need to be reduced when running larger material through a drywasher?

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You need to Tune it!

Change the angle of the Riffle Tray.

How Fine is the Gold?

It would be best to classify the material to that size or close.

Change the angle until the gold stays in the first three riffles.

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I would also check two other things: Have you left this machine out in the weather where moisture could dampen the riffle material, if you have been running

material containing clay and /or calchie and is exposed to dampness it will coat the cloth, causing your problem, if so wash it and blow dry it.

While you are looking check for a dead air space behind each riffle. Lower the angle as was suggested.

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Typical of a puffer, thats why the industry standard is constant flow and good to go with MUCH better recovery and hump a bump just don't do it good enough. Classification is king on all units and they're only as good as the operator-John

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You need to Tune it!

Change the angle of the Riffle Tray.

How Fine is the Gold?

It would be best to classify the material to that size or close.

Change the angle until the gold stays in the first three riffles.

Works good with fine gold as long as everything being ran is the same size. However, when I run the larger material, it spits out the gold. I am thinking I need to decrease angle.

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Your target angle is determined by the ratio between the height of the riffle/distance between the riffles. The ideal angle is when the top of the downstream riffle is dead level with the trailing edge of the upstream riffle.

A plumb bob is an excellent tool to use to determine the angle in the field. Find the opimum angle on a solid floor and hang your plumb bob from the hopper. Make a mark on the table where the plumb rests. Then in the field all you have to do is hang the plumb bob and adjust your machine for the perfect angle.

I screen to 3/8" and lose very little. You wont find a particle past the third riffle unless the material is wet or has lots of clay.

Bob

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Typical of a puffer, thats why the industry standard is constant flow and good to go with MUCH better recovery and hump a bump just don't do it good enough. Classification is king on all units and they're only as good as the operator-John

How much of it is supposed to be moved from air flow versus tap of the bellows? I think your saying that leaf blower powered dry washers are more efficient than puffers. I guess water can't be beat, but it sure is hard hauling around all that water.

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How much of it is supposed to be moved from air flow versus tap of the bellows? I think your saying that leaf blower powered dry washers are more efficient than puffers. I guess water can't be beat, but it sure is hard hauling around all that water.

I have run both blower and puffer allot and if the drywasher is set up correctly and dirt dry the recovery is close to same for me...

Most of my gold is as mentioned above in the first few riffles.

Main reason I run a puffer is to not have to use a gas engine and just me :inocent:

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It would help to know what model drywasher you are using and some details about whether the cloth is fastened to the riffles or if the riffles merely get seated atop the cloth. Also, what are the riffles made of? [metal, wood, plastic or what] And what shape are the riffles [straight up and down, inclined back, with dead space, without dead space, etc.]?

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It would help to know what model drywasher you are using and some details about whether the cloth is fastened to the riffles or if the riffles merely get seated atop the cloth. Also, what are the riffles made of? [metal, wood, plastic or what] And what shape are the riffles [straight up and down, inclined back, with dead space, without dead space, etc.]?

It is a pretty basic drywasher and homemade. The riffles are attached to the cloth/no slack under the riffles. The riffles are just square with no angles.

I will try to reduce the angle when running larger material and see if it helps. It just doesn't look like the gold is sinking down, but is popping on top and roiling down to the last riffle. Occasionally falling off the last riffle. However, when running small stuff at the same angle, it retains all the gold.

If this is not common behavior for a puffer, and cannot be corrected, I may simply buy another model.

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Oldsalt you stated the riffels are SQUARE pieces ???? This doesn't sound good or even right.

In other words the riffel is made like a 1x1 piece or 3/4 x 3/4 for example.??? If so This is no good.

A degree of bevel is nessessary on the rear side / upstream along with a dead air space to catch AND retain heavy particles.

If you were to make a new tray with approximately a 37 degree bevel on the rear of each riffel along with a dead air space of approx. 3/8th" it would perform much better and more consistently.

And generally the flatter you can have the riff. tray and still maintain flow is best when set up to run.

I believe in the old ways and those are what I was taught. The results will speak for themselves.

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Oldsalt you stated the riffels are SQUARE pieces ???? This doesn't sound good or even right.

In other words the riffel is made like a 1x1 piece or 3/4 x 3/4 for example.??? If so This is no good.

A degree of bevel is nessessary on the rear side / upstream along with a dead air space to catch AND retain heavy particles.

If you were to make a new tray with approximately a 37 degree bevel on the rear of each riffel along with a dead air space of approx. 3/8th" it would perform much better and more consistently.

And generally the flatter you can have the riff. tray and still maintain flow is best when set up to run.

I believe in the old ways and those are what I was taught. The results will speak for themselves.

Good idea. I do have the dead air space, but the riffles are just straight and square. I will modify them, and adjust the tray angle. Thanks.

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Good idea. I do have the dead air space, but the riffles are just straight and square. I will modify them, and adjust the tray angle. Thanks.

A little "dead air" space also helps at the riffles. Use silicone and tape to make a 1/8 inch "dead spot" on the fabric at each riffle to help catch fines better after you do your mods...

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