Dry Blower

[1968falconxt]

Occasional_Panner, This is what I have. You have me concerned now that my opening is too big. If mine lets too much material through even when only slightly opened, I will have to bolt in a piece with a triangular opening instead.

I also listened to you regarding the size of the unit and scaled it back to be similar to the Keene 140. What sized expanded mesh do you recommend? I have no idea what size classification is required.

 

[Keitzy]

Yup, what OP said, the triangle opening on my hopper works heaps better. Once
Materials classified threw the mesh/grizzly there's no big stones or rocks to slow it down so she can pour out pretty easy.

 

[Occasional_panner]

It won't be perfect first time around, just add a plate inside, easy.

That size looks very sensible :Y: :Y:

My expanded mesh is probably 15mm wide and 10mm high, but that really will depend on what you are running.

Also since you are set up pretty well with machinery it might be an idea to make another riffle tray with smaller riffles, it's always good to have options when testing new stuff.

Lookin good :Y:

 

[1968falconxt]

It won't be perfect first time around, just add a plate inside, easy.

That size looks very sensible :Y: :Y:

My expanded mesh is probably 15mm wide and 10mm high, but that really will depend on what you are running.

Also since you are set up pretty well with machinery it might be an idea to make another riffle tray with smaller riffles, it's always good to have options when testing new stuff.

Lookin good :Y:

That's a great idea regarding the riffle tray. I will make up another one. I'll try that sized expanded mesh but will buy a couple different sizes so I can pick and choose. I have already made up a fill in plate now to slow the dirt flow down based on your and Keitzy's opinions.

 

[Occasional_panner]

You won't break it all up in the first go, some will fall off and end up in a pile at the back, just wait till the pile is big enough and shovel it back again.
Try that size mesh first, I'm sure you'll be happy with it. When you fit it there is a direction to it, have the lifted up bits facing up.

 

[Keitzy]

...and i always find its easier to fill buckets to pour in the hopper then shoveling straight into it. Helps keep the rifle tray loaded and working all the time. ..

 

[Occasional_panner]

Yes, what Keitzy is referring to is that the riffle tray needs to have dirt on it all the time, you can't start-stop and let it run out continuously The way it works is by having a back pressure from the dirt to evenly distribute the air among all the riffles.

 

[1968falconxt]

What angle did you find was best to achieve this? I read that 20ish deg. is a good starting point. Also, as you suggested making another tray with smaller riffles, what size do you think? My current ones are 25mm high.

 

[Occasional_panner]

I think mine are 15mm high, but mine is a bellows type, just test with some spraypainted lead and put it in some sand and see where you recover it, use a blade and make some fine shavings, then chop them up a bit. Even shallow riffles recover gold in the top two or three.

 

[Keitzy]

Yeh, 20ish is a good point to start. Just adjust till the dirts flowing over the riffles like a little waterfall. Mine are 15mms as well. The larger ones I made backed up the tray to much and clogged the space behind the riffles.

 

[1968falconxt]

I have just gone with 15mm on my new tray. 25mm just looked too tall. But I will experiment with both.

 

[Occasional_panner]

From previously building alluvial stuff, I couldn't get my head around how small the dryblower riffles needed to be.
15mm looks small but it works, and most of your catch will be in the top tho riffles.

 

[1968falconxt]

I guess you want the vibration to do most of the work. Tall riffles would require so much more air to move the dirt down the line and it might push gold with it too. I am glad you suggested making up another riffle tray.

My riffle tray material finally arrived from Reeds so now if the zinc platers ever get around to plating the riffle trays I can actually start testing the dry blower...

 

[Keitzy]

How'd u go with making a shaker fan mate? Did u nut it out or just buy one in the end.?

 

[1968falconxt]

I have made one and am waiting on a couple of bearing bushes to be made. No idea if it will work yet but I will trial it soon. I have several different sized weights to bolt on too.

This is how I went about it. (Fan blades will be bent to close up as much gap as I can so the air has no choice but to push past the blades).

 

[Keitzy]

Looks the goods... not to sure how the flat blades will work tho, mine are bent at roughly a 30-45ish degree angle. It spun much faster with them bent.

 

[1968falconxt]

I meant I will bend them to as much angle as the frame will allow (I will aim for 45deg). It's only flat because I didn't bother spending any time drawing it properly as I have cut a few sized fans to trial

 

[Keitzy]

Lol ok, misunderstood sry.

 

[Occasional_panner]

It would be good if you had a bearing carrier that supported the counterbalance top and bottom, the rpm and vibrations being carried from one side will cause unwanted stress.

Edit, you could have the shaft extent up past the carrier frame and have an identical counterbalance on the upper side, not quite as sturdy but would balance the load a tad better.

 

[Occasional_panner]

Looks the goods... not to sure how the flat blades will work tho, mine are bent at roughly a 30-45ish degree angle. It spun much faster with them bent.

Always good to see you're on the ball mate :|

Lol can you do my tax return.

Just stirrin mate :Y: