Introduction: A Gas-powered Vacuum Cleaner for Use in Gold Prospecting
One of my many hobbies is recreational gold prospecting. I've been gold panning on my vacations for many years. It's a lot of fun. It's great exercise. I get to do it in really scenic locations. I have even found some gold. Gold likes to collect in cracks and crevasses and really hard to get at nooks and crannies. What is really needed to clean out those pesky cracks and crevasses is a vacuum cleaner. Problem is, where do you plug it in out in the wilderness? Solution, replace the electric motor with a gasoline engine. Now you have a vacuum cleaner that will work anywhere.
As with most of my other equipment, (recirculating sluice, wind turbine, solar panel, telescopes, jet engine, etc., etc.), I decided to try building one myself, rather than just buying one. The tinkering is half the fun after all. Also, you will get a much greater sense of satisfaction and accomplishment when you know it is YOUR home-built equipment that is doing such a good job, and not some store-bought thing. You can find more information on my various projects at http://www.mdpub.com
Step 1: Find a Cheap Wet-dry Vac
The first step in the process is acquiring a small, wet/dry vac cheap. I found one at a yard sale. It was in pretty bad shape. The guy swore it worked though. I didn't really care if it worked or not because I was going to take the electric motor off anyway, but I didn't tell him that. I kept talking him down in price because of how beat-up it was. Eventually I got it for $5. Maybe I'll write an instructable on haggling.
Step 2: Replace the Electric Motor With a Gas Leaf Blower
Now I needed to replace the electric motor with a gas engine. Well I already had a leaf blower. It is engine and blower unit in one. That's half of a vacuum cleaner right there. All I needed to add was a tank and a hose, and the wet dry/vac I just bought had them.
I removed the nozzle extension and the intake diffuser from the leaf blower. This turns it into quite a compact unit that will sit comfortably on top of the tank of the wet-dry vac. The pieces just snap right back on when I need to do lawn work.
Step 3: Make a Top Plate for the Vacuum
After I removed the electric motor and blower unit from the wet/dry vac, I contemplated how to attach the leaf blower in its place. I decided to just cut a disk of plywood that would fit over the top of the wet/dry vac's tank. I used a jig saw to cut it out of a piece of 3/4 inch plywood I just happened to have lying around. I put three screws in with their heads sticking up a little for the hold-down clips on the tank to get a grip on.
Then I cut holes in the disk to accommodate the leaf blower. I not only needed a hole for the leaf blower's air intake, but also holes for various protruding pieces that would otherwise be in the way and not allow the leaf blower to sit all the way down flat on the disk.
The third photo shows the leaf blower test fit on the top of the vac. It looks good, but there are a lot of air leaks that prevent the vacuum from developing good suction. I needed to add weather stripping.
Step 4: Seal With Weather Stripping and Screw Down the Blower
I got some thick, adhesive-backed weather stripping at my local home center store and used it to ensure an air-tight seal between the leaf blower and the wood disk. Caulking would probably work better, but I wanted to be able to remove the blower easily when I needed it for yard work. If you have a leaf blower you are willing to permanently dedicate to this application, then caulking may be the way to go.
Then I used long wood screws and washers to hold the blower down on the wood disk. My model of leaf blower has convenient tabs on the edges to run the screws through. It only takes a couple of minutes and a screwdriver to free it up when I have to use it for yard work.
Step 5: Finished!
There is the "finished" product. There are a couple of issues that still need ironing out. I need to put handles on it somehow so I can pick it up easily when it is full of dirt. Picking it up by the leaf blower handle isn't going to work. Also, there is no automatic shutdown mechanism when the tank is full like the original electric unit had. I'll just have to keep an eye on the level of material in it. I can't wait to take it out in the field and give it a try.
Note: If you build one of these, I highly recommend you use ear protection while running it. It is very loud and the hose isn't long enough to allow you to get too far away from it. Also, a dust mask would be a good idea. This unit has no filter, and so blows a lot of fine dust out when vacuuming up dry material.
More information on my projects can be found at http://www.mdpub.com