What do You Want on your 'Zooka?

[Goodyguy]

Zombie thread! Grrr, Arrrg.

I'm building my first sluice. This place is a goldmine of knowledge, thanks everyone.

I was wondering about putting some riffles or something on the tailings deck (I think that's what it's called. The upper deck that larger material travels over after crossing the grizzlies) just to catch, at least temporarily, any larger heavies or (optimistically) nuggets that are too big or happen to ride the rails. I remember seeing somewhere in a fluid bed test a flake of gold that had escaped and they were pretty sure that it was because it was shaped just right to slide up a grizzly and over the top.

Anyway, does anyone have any thoughts about what sort of riffles would be appropriate in this scenario? I was thinking square-profiled slots slightly larger than the grizzly classification.

Bonus: Here's my design thus far. I picked up a 4x8 sheet of 3mm ABS today. I haven't quite figured out the vertical dimensions or tubes yet.

I like the basic concept of your design!
The wider trap should slow down the flow enough to give fine and flour gold plenty chance to drop out. (same principal as when a stream suddenly widens causing the gold to drop out of the flow due to the lower pressure)

The challenge is to supply the fluidizing tubes with enough velocity to keep the larger trap fluidized properly.
Something to keep in mind when choosing the number, diameter, placement of the tubes, hole sizes, etc.

Pretty sure that hurdle can be overcome with the proper modifications to make your design a superior gold catcher.


I also like your use of a flat non-elevated grizzly. It works great for me.
Your idea of using drop riffles on the discharge deck as a fail safe is also sound (it couldn't hurt)


Please keep us posted on your results.........


Go for the Gold
GG~

 

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[Caconym]

Thanks for responding Goodyguy, I hoped you would. Pretty much every element of my design comes from something you've written at some point. Slowing the flow was exactly the thinking behind the wider trap.

May I PM you for your maths on the number of jets please? I assume the formula is a closely held corporate secret.

Do you have any thoughts on laminar flow across the top of the trap vs baffling?

I'm thinking of changing the dimensions from "backpack" to "car and kayak", which would allow a longer and wider water capture area. I'm also thinking about incorporating your hinged intake concept.

Another idea I had for increasing volume of water capture was ditching the rigid design we all use in favour of tarpaulin with heavy wire sewn into the mouth for rigidity. This would be attached beneath the transport deck and bellow out. This could be significantly larger while still being light and packable. I may try that down the line but I thought I'd throw it out there in case it inspires someone.

 

[arizau]

Thanks for responding Goodyguy, I hoped you would. Pretty much every element of my design comes from something you've written at some point. Slowing the flow was exactly the thinking behind the wider trap.

May I PM you for your maths on the number of jets please? I assume the formula is a closely held corporate secret.

Do you have any thoughts on laminar flow across the top of the trap vs baffling?

I'm thinking of changing the dimensions from "backpack" to "car and kayak", which would allow a longer and wider water capture area. I'm also thinking about incorporating your hinged intake concept.

Another idea I had for increasing volume of water capture was ditching the rigid design we all use in favour of tarpaulin with heavy wire sewn into the mouth for rigidity. This would be attached beneath the transport deck and bellow out. This could be significantly larger while still being light and packable. I may try that down the line but I thought I'd throw it out there in case it inspires someone.

I read somewhere that the largest Bazooka Gold Trap was almost a two man job to get un-wedged and out of the river due to current speed and added water weight etc. so maybe you should take that in consideration for your sizing for the car kayak sluice.

Love the idea of the canvas scoop.

Good luck.

 

[Goldwasher]

I read somewhere that the largest Bazooka Gold Trap was almost a two man job to get un-wedged and out of the river due to current speed and added water weight etc. so maybe you should take that in consideration for your sizing for the car kayak sluice.

Love the idea of the canvas scoop.


My partner had one of the first miners sold. It took two of us to get it out of the creek. Never tried it in a river. too big for hiking.


The soft scoop is an ok Idea the connection of frame to deck is going to be problematic.

 

[Goldwasher]

Thanks for responding Goodyguy, I hoped you would. Pretty much every element of my design comes from something you've written at some point. Slowing the flow was exactly the thinking behind the wider trap.

May I PM you for your maths on the number of jets please? I assume the formula is a closely held corporate secret.

Do you have any thoughts on laminar flow across the top of the trap vs baffling?

I'm thinking of changing the dimensions from "backpack" to "car and kayak", which would allow a longer and wider water capture area. I'm also thinking about incorporating your hinged intake concept.

Another idea I had for increasing volume of water capture was ditching the rigid design we all use in favour of tarpaulin with heavy wire sewn into the mouth for rigidity. This would be attached beneath the transport deck and bellow out. This could be significantly larger while still being light and packable. I may try that down the line but I thought I'd throw it out there in case it inspires someone.

no corporate secret. at least six holes 5/16 is good

I say eight holes at 5/16 The trap is really hard to over fluidize with natural flow. an active trap isn't going to spit out gold.

I built close to a thousand Bazookas and I always thought we should have had bigger holes in the tubes.

Whenever I was in a lower flow situation I always wanted a more active trap.

 

[Goldwasher]

BTW this lil' guy flew in the cockpit of a Quantis Jet, and was brought to me by the owner of the Co.

If there seems to be enough demand in the market they may start being produced and available in the U.S.

Just like Bazookas we shipped internationally the cost goes way up.

People like Bazookas especially the build quality. They are very strong.

These are exact copies made with the same strength with streamlined production.

So, if anyone is wanting a " new"
Bazooka type gold trap.

It may just be happening.
I'll be one of the first to know..
Then you guys!!

I'll keep you posted

 

[KevinInColorado]

You can already get a new Goldtrap sluice...with real improvements including increased fluidization flow as Goldwasher mentions above. Grizzly Goldtrap is also a sponsor here so I can point you at their site. The owner is a friend of mine and a fellow Coloradan. The sluice is entirely US made too. www.grizzlygoldtrap.com

Oh, and I have the midsized model. It works better than the Bazookas did. Easier to set up, has indicator riffles to show you are on the gold, better fluidization and fluid bed engineering means it catches -100 gold far better than the Bazookas.

 

[Caconym]

^ The gold trap Goldwasher pictured above is by Croc Gold Traps out of Queensland Australia. They're pretty expensive but seems to really like them.

 

[Goldwasher]

^ The gold trap Goldwasher pictured above is by Croc Gold Traps out of Queensland Australia. They're pretty expensive but seems to really like them.

Make sure you change the currency to US.

Yes they are pricey. They go for the same price as Bazookas did in Australia. Shipping them there was almost as much as the box. Same to get a Croc shipped here.

They have made major production improvements.

They are trying to figure out how to get them made here so they won't be so pricey.

 

[Goodyguy]

Thanks for responding Goodyguy, I hoped you would. Pretty much every element of my design comes from something you've written at some point. Slowing the flow was exactly the thinking behind the wider trap.

May I PM you for your maths on the number of jets please? I assume the formula is a closely held corporate secret.

Do you have any thoughts on laminar flow across the top of the trap vs baffling?

I'm thinking of changing the dimensions from "backpack" to "car and kayak", which would allow a longer and wider water capture area. I'm also thinking about incorporating your hinged intake concept.

Another idea I had for increasing volume of water capture was ditching the rigid design we all use in favour of tarpaulin with heavy wire sewn into the mouth for rigidity. This would be attached beneath the transport deck and bellow out. This could be significantly larger while still being light and packable. I may try that down the line but I thought I'd throw it out there in case it inspires someone.

Sorry I do not have a mathematical formula that takes all the variables into consideration. I built my first fluidbed sluice with what seemed to be reasonable dimensions to my way of thinking and then tweaked from there using trial and error based upon field testing.

Since then I have developed a working knowledge of the variables involved with achieving proper fluidization of varying size and shape traps in relation to the input flow and overall sluice configuration. There is no one size formula that fits all in my experience.

Not sure what you are asking about laminar flow vs baffling? I assume you are referring to smooth flow vs turbulent flow.
In laminar flow all the particles are flowing at approximately the same relative speed. Turbulent / chaotic flow causes the particles in the flow to have a more difficult time settling out of suspension due to the higher velocities involved.

In the case of a fluid bed trap that is located at the discharge end of a sluice too much turbulence can cause scouring (boil box effect) which can lead to gold being lost due to it not being allowed to fall out of suspension. Baffles that create scouring and therefore loss of gold should be avoided.

I have not tried my idea of using a series of soft baffle strips to divert the gold that is riding the surface of the laminar flow out of suspension, but the idea sounds feasible to me. Seems to me that it would work without causing any undue turbulence.

Every hard baffle or diverter strip I have tried was either ineffective if it was too small or caused scouring if it was too large.
Hard to get the size just right because of flow velocity being such a variable.

I had better luck with a single soft damper flap which kept the flow more laminar no matter the flow velosity.


Good luck with your project.
For us tinkerers there is no substitute for trial and error based upon comprehensive field testing.

Go for the Gold
GG~

 

[goldog]

Thanks for reviving the thread Caconym. Can’t have too much fluid bed discussion.

Goodyguy is right to talk about scour vs laminar flow. But I’m surprised you say no baffle. Bazooka used a 1/4” strip inside the upper deck. Just a little down force to help prevent surfing. I doubled up on most of my builds. Seem to get good results.

One thing I noticed on the tubes. The conduit pvc seems best. Sch40 with a thicker wall seemed to me to not provide as much pressure.

Boy are those selling at that price. Australian or not, that’s a lot!

 

[Goodyguy]

Thanks for reviving the thread Caconym. Can’t have too much fluid bed discussion.

Goodyguy is right to talk about scour vs laminar flow. But I’m surprised you say no baffle. Bazooka used a 1/4” strip inside the upper deck. Just a little down force to help prevent surfing. I doubled up on most of my builds. Seem to get good results.


One thing I noticed on the tubes. The conduit pvc seems best. Sch40 with a thicker wall seemed to me to not provide as much pressure.

Boy are those selling at that price. Australian or not, that’s a lot!

Not necessarily no baffle, just something that does not cause any gold loss due to scouring.
Does not matter what you use, if it works, then the proof is in the pudding.

Definitely a good idea to have a way to keep gold from surfing out of the trap.

Personally I like the soft damper flap because it is not so sensitive to flow velocity variations.
Also the flow characteristics into the trap are somewhat different when using a level grizzly (the one I prefer) vs the elevated one used on the current production models.

GG~

 

[KevinInColorado]

Make sure you change the currency to US.

Yes they are pricey. They go for the same price as Bazookas did in Australia. Shipping them there was almost as much as the box. Same to get a Croc shipped here.

They have made major production improvements.

They are trying to figure out how to get them made here so they won't be so pricey.

Maybe they should partner up with Grizzly Goldtrap. I know Dennis sent a shipment to NZ last month. Seems silly to ship sluices back and forth over the Pacific Ocean!

 

[Caconym]

Construction has begun! Coffee mugs not to scale.


I'm taking my time to try and do it well, though as my first build and not a direct Zooka clone I know it will need tweaking and probably re-doing.

A white Sharpie marker has been really useful for working with the black ABS.

 

[Goodyguy]

Construction has begun! Coffee mugs not to scale.
View attachment 1568186

I'm taking my time to try and do it well, though as my first build and not a direct Zooka clone I know it will need tweaking and probably re-doing.

A white Sharpie marker has been really useful for working with the black ABS.

As Goldog, I, and other fluidheads can testify to, it's easy to get hooked on tinkering with the fluid bed concept.
Welcome to the fold
You will never be the same.

GG~

 

[goldog]

Less is more. The enemy of good is great...

Darn right! Tinkering is a lot of fun. And frustration. Kinda like having kids.

Plan well. Keep it simple. Get finished. Only make small design changes. One at a time. Test. Always look for the downside.

 

[Caconym]

I finished the gold trap. Tomorrow I'll take her out and see if she works. Here's a build album if anyone's interested.

 

[Caconym]

Took her out for a test run. I should mention this was only my second time fossicking.

I'm not getting enough fluidisation, and there was some scour, but that's not a huge surprise; that's what test runs are for. I'm thinking I may have too many holes (about 38 2.4mm holes per tube, based on dividing the area of the cross section of a tube by the area off the cross section of the drill bit). I'll have a tinker and see what can be done. I may remove some height from the exit so as to lower the holding height of the trap, too.

On the plus side, it clears oversize stones with minimal intervention or jam-ups, and I caught my first ever gold with it! Dammit, now I'm hooked.

I think the flat grizzly design is a winner. I don't think the curvaceous design added anything to the function of the trap, but that's okay, it looks sexy. The vinyl flap kept catching sand on top of it, so I may shorten it.

Video doesn't show much, but oh well.

 

[KevinInColorado]

This is cool if you are having fun. Understand you are reinventing the wheel. It will take a lot of experimentation to get it working well...meanwhile you will be producing less gold. In the end you will most likely spend just as much on materials as you would have on a commercial sluice. But hey, enjoy the ride!

 

[Goodyguy]

Took her out for a test run. I should mention this was only my second time fossicking.

I'm not getting enough fluidisation, and there was some scour, but that's not a huge surprise; that's what test runs are for. I'm thinking I may have too many holes (about 38 2.4mm holes per tube, based on dividing the area of the cross section of a tube by the area off the cross section of the drill bit). I'll have a tinker and see what can be done. I may remove some height from the exit so as to lower the holding height of the trap, too.

On the plus side, it clears oversize stones with minimal intervention or jam-ups, and I caught my first ever gold with it! Dammit, now I'm hooked.
I think the flat grizzly design is a winner. I don't think the curvaceous design added anything to the function of the trap, but that's okay, it looks sexy. The vinyl flap kept catching sand on top of it, so I may shorten it.

Congrats on a great build!
As well as getting some gold with it.

I think you are on the right track to lower the exit port. From the photo it appears that there may be a little too much room from the top of the tubes to the bottom of the exit port. Anything over 1-1/2" is too much. I prefer 1-1/4"

How far are the bottom of the tubes off the bottom of the trap? 1/2" is the norm.
You also want to make sure the exit port is large enough to handle the throughput without hindering the flow.


You can not put a price on the feeling of satisfaction, pride of workmanship, feeling of accomplishment, learning from hands on experience, enjoyment of the ride, etc. all from building it yourself........ It's a "tinkering thing"


Go for the Gold!
GG~