My Bunnings Sluice Design

[grippsy25]

After seeing another member of the forum (Ryan J) do a Bunnings build recently I've been inspired to build my own in a similar vein.

Im only in design process right now for a couple of reasons: a) holding out hoping I win the sluice in the Easter Raffle haha and b) I'm still pretty new to this whole thing and I predict I'm going to NEED some feedback, so no need to rush into the build and end up with a "sluice" that doesn't work.

So I tried to do research before I started but found info to be fairly scarce. In terms of things like overall size, shape, length and riffle size, shape, spacing etc there doesn't seem to be any definite answers. Lots of answers such as "depends on how much water flow you'll have", or "depends what size you'll be classifying your material" etc. Not exactly what I was looking for, but helpful none the less. So all in all, my research taught me that pretty much any design (within reason) will catch gold...some just more than others.

So without the guidance I initially wanted I went about designing the sluice on paper...the following is what I've come up with. Who knows if it's workable or not...certainly not me. This is where the knowledgeable people here come in and critique it for me, tell me what'll work, and what won't...then I can get the built right the first time.

Just FYI, I rounded off numbers here or there but they're basically accurate. And the pics are a little askew since I didn't get them from directly above, so ignore that too

Specifications: (all dimensions shown in millimeters)
Overall Length: 750
Flared Mouth Length: 180
Flared Mouth Width: 290
Riffle Section Length: 570
Riffle Section Width: 190
Riffle Spacing: 69
Riffle Length: 31
Riffle Height: 17.5
Wall Height: 70

Materials list: so far...
- Marine Ply
- Corner Brackets (x10) -> I'll be using rivets like Ryan J used.
- Bayliss 40x60cm Synthetic PVC Mat -> once cut down I'll get two mats to use from the 40x60 mat
- Pine Riffles 35x10xVarious lengths -> free, got a bunch lying around.

Not sure what adhesive I should use. Ryan J used Araldite...guess I'll get that too unless there is something better to use? After all, if I recall Ryan J said he already had the araldite lying around.
Also, for the flared out section, Ryan J put in chopping boards in there...is there a specific reason the chopping boards were used? Could I use something else, like a 5mm acrylic sheet, for example?

All in all, looks like I'll be able to do this build for about $65 (costed via the bunnings website). Not a bad price for a (hopefully) functional sluice. Plus, it's an excuse to play with the power tools for a couple of hours

Now, the riffles im not really sure about. I don't know if they're too tall or too short, a good or bad shape, a good or bad angle, to wide or too narrow....I'm lost. Are timbre riffles even workable at all? I have a sneaking suspicion that this is where I might have to make changes. Th reason im not using metal is because I don't have the skills or tools to work with metal, so wood it is. We'll see...

My idea is to use 35x10 dressed pine for the riffles, routing two opposing edges to end up with a parallelogram. This give me a riffle with the dimensions shown in the picture below. Im not sure how well the pine will hold up, but I've already got it so I'll try it for now.

As you can see that process will give me 17.5mm high parallelogram shaped riffles. I'll then take two strips of the marine ply and fix them to the outside of the riffles (making something resembling a ladder so I can lift the riffles out to remove the mat for cleanup). How do you think the riffles themselves will work? The spacing okay? And just the general set up?

Basic design, shape and dimensions

Riffle shape and size

Water flow would be from right to left in picture above.

Riffle Strips

In case I wasnt clear I thought I would try and draw a picture to illustrate.
18mm high, with 40mm wide sections raised level with side of sluice (70mm in pic, but will be smaller depending on thickness of the mat). I needed a way to make sure the riffle "ladder" sits firmly in place down against the bayliss mat, so decided to have the raised sections through which I'll pop a bolt with a wing nut for easy removal. Three raised section on each side...one at either end and one in the middle should hold it firmly in place.

So hopefully someone can make sense of all that and give me some guidance before I go any further. Thanks in advance.

 

[Ryan J]

Hi grippsy25 glad I inspired someone to do the same. I felt like araldite was the only option for me as it needs to be waterproof pva just wouldn't cut it & sikaflex just doesn't have the same holding power on such a small area liquid nails may work.

As for the chopping board it is only there to slick it up and prevent abrasion to the wood so anything will do but those sheets are less than 1mm thick and extremely durable. It will eventually get a fury surface on it otherwise now for sticking it down the araldite did hold them on for one outing but on the second the washed off not a trace of glue on the nylon at all I sanded them back and everything maybe contact adhesive next time.

The mouth size I took into account the size of my sieves I want to be able to shake the material out in the mouth of it.

riffle height mine are 30mm high and I am catching plenty of flour gold (nothing but it yet)

flaws I have found in mine so far where the mouth walls meet the side walls while still holding strong I thing there is the potential for them to crack apart one of the bend yourself brackets each side will help allot I think. if you are putting straps on it (I highly recommend leaves hands free for bucket pan shovel) and throwing it in the back of a ute strap side down will wear the straps top side down will wear the timber I plan on screwing a dome head screw every 75mm along the top of the walls to overcome this problem. Bolts and wing nuts material builds up in the mat under the riffles putting pressure on the bolts making it impossible to get out by hand a screwdriver is needed. also I have a carry handle to put on the side of it as well but I got too keen to use it.

hope this helps

 

[Ryan J]

oh yeah the pine will probably warp and bend from the moisture but if the are easy enough for you to make up they are replaceable

 

[grippsy25]

Yeah that's what I was thinking re the pine. But it's readily available for now and doesn't take long to knock up so I'll give it a crack. As long as I get more than one or two uses out of it. Araldite seems to be the way to go...if it works, then it works. Good tip re bend yourself bracket for the side wall/mouth wall meeting...they're on the list. And the screws to stop wear...another good one. 30mm high riffles are a fair bit bigger than mine....mine seen too small? Perspex/Plexiglass/Acrylic Sheet should work alright instead of the chopping boards then it seems. Going to use a nice sigle black piece I think...

Thanks mate

 

[Ryan J]

Im only new at this game aswell so riffle height I don't know much about im thinking mine are too large my next riffle bar I make up will be 20mm if you have to buy the Perspex I would go with the chopping board supermarkets and cheap shops sell them I also had the very back of them unglued to tuck the matt slightly under to stop material from washing under it. Perspex should work fine though

 

[Goldtarget]

Forgive me for asking but without inferring anything i wonder if building one is the easiest method, there are some really cheap options in this area that do a fantastic job that is a case of order, pay, receive, and then use. I could list many options but if you decide to go down the diy track then keep in mind that it would be better to wait and buy the best quality materials that will last over the long term, nothing more frustrating than taking time to go out in the field only to be thwarted by an equipment failing. Good luck with the build though, some good thoughts going on here.

 

[grippsy25]

Easiest option? Certainly not. But I'm between jobs right now so the build excites me almost as much as the gold. Plus, I think catching gold with your own creation would all the more satisfying.

And I don't need this thing to last years. Im more interested in detecting for gold but that's not on the cards until I find a new job so this could be a cheap and cheerful way to keep me entertained and get some gold in the meantime.

 

[Goldtarget]

Excellent points. Very frustrating not being actively employed, and i wish you luck on that front, i hope it doesn't last too long, may you find something suitable. In the meantime what better way to fill the hours, i have been an active diyer on the gold equipment myself, and i hope you find it equally satisfying and enjoyable, followed by many colours in it's outings. Best of luck mate, I'm sure things will pick up soon enough.

 

[grippsy25]

Tell me about it...the boredom is immense. Sigh. I too hope it doesn't last too much longer but it's not exactly raining jobs right now and is proving rather difficult. It has been quite a few months that I've been out of work so I'm annoyed that I'm just getting into this now...I wasted a few months of good prospecting time. Derp Oh well...I'll be hitting the streams within a couple of weeks and I'm sure I'll forget about all my worries (while I'm out there at least)

 

[Ryan J]

I'm just a tight ass