My Homemade Sandblasting Pressure Pot

[ronh72c10]

Just a warning, this project involves welding on a pressure vessel, something dangerous at the best of times, it is possible that the tank may fail and seriously injure or kill someone. Be careful and be warned.

Hi all, another member asked for more details on my homemade pressure pot sandblaster. Here's a few pics and a shopping list for parts.

Here's an overall pic of the unit, the basic operation is that the tank is pressurized on the top of the tank with a line bringing straight air around to the bottom to help carry the sand from the bottom opening in the tank thru to the nozzle.

[ronh72c10]

This is a detail pic of the top showing the 3/4" loading valve, a shutoff for the air inlet and a third valve to the bottom to control airflow. I will admit that the airflow valve is almost always wide open. Just a warning, some of the valves may seem to be unnecessary, but they are really needed to

prevent backflow of the sand when you depressurize the tank. I put a gauge in the top in an existing fitting, but it's really not necessary, for safety reasons it might be a better idea to replace it with a relief valve.

[ronh72c10]

This picture shows the bottom of the tank with the sand control valve, it's a bit touchy and I wish there was a better way to control sand flow, but this is the best I've come up with so far. I tried to keep the welding to a minimum, but I needed to drill a hole in the bottom of the tank, over that hole I welded a 3/8" pipe coupler. My welding doesn't look so good in the picture, as well the bottom looks a little rusty, not the sort of thing you want to play with, I may retire this tank and redo it just to be safe, I can reuse almost everything and a new tank is only $20.

[ronh72c10]

The only other part I welded on was the carrying handle. As well here's a shot of the bottom wheel structure that was all made with 1/2" conduit bolted together.

[ronh72c10]

Shopping List:

Most everything came from Home Depot, but nothing except the Sandblast valve is special.

1 - 20lb Propane Tank
3 - 3/8" ball valves
1 - 3/4" Ball Valve (sand filler)
1 - Sandblast Valve/Nozzle, the inlet was 3/8" yours may be different, mine unit came from Princess Auto, but Harbour Freight has them as well
- A length of 1/2" Reinforced water line, from the tank bottom to the sandblast nozzle, originally I used 3/8" but it kept plugging and rather dramatically burst. After that I changed to 1/2" line and it all worked fine. Keep an eye on the line, the sand erodes it and eventually it will burst.
- Length of 3/8" Reinforced water line, just a short length is needed, if you switch to 1/2" on this line it would be fine and you would only need one
diameter of line.
1 - 3/4" pipe tee, for the top, check the diameter of the large hole in your tank, it may be larger, if so all of the 3/4" fittings should be changed to the appropriate size.
2 - 3/4" close pipe nipples, for the top
1 - 3/4" to 3/8" pipe reducer, for the 3/4 tee to 3/8" tee
2 - 3/8" pipe tees
3 - 3/8" Close pipe nipples
1 - 3/8" pipe nipple 3" or 4", basically that long for clearance for the valve handle.
1 - 3/8" Pipe Coupler, welded into a hole in the bottom of the tank.
2 - 3/8" Pipe to 3/8" hose barb
1 - 3/8" to 1/4" reducer (for air inlet)
1 - 1/4" Air line inlet (male)
1 - Air pressure gauge or relief valve
- whole bunch of 1/2" conduit (for me around 109")
2 - lawn mower wheels
2 - 3/8" to 1/2" hose barbs (one sized for the Sandblast Valve/Nozzle)
1 - 3/4" hose barb for the top fill valve as well as a large funnel (not mandatory)
- Threaded rod for an axle for the wheels.

Hopefully this gives somebody some ideas.

Ron

[SevenSeries]

Thanks Ron, extremely helpful! What kind of material do you use to blast with?

[ronh72c10]

I've been using the "black sand" from TSC, I've always assumed that it's coal slag but it might just be sand. I wouldn't use it to blast any body panels, you'll risk warping. It's really only suitable for heavy gauge metal like the frame.

I'll also say that I found it to be alot quicker and easier to clean up the frame with wirewheels and flap disks, just wear a leather apron and a face mask since those little wires fly everywhere. Just use the blaster to get into the spots that are a little inaccessable, it goes way quicker.

Ron

[Hottrucks]

welding a used propane tank will get you killed.....propane penitrates the tank steel and the residgual gas will be nearly impossable to get out...they seel a special poweder to put in the tank but I recomend getting a new tank..this is no place to be cheap!!

[Shane]

so use a freon tank instead ...

[ronh72c10]

At the time I made it, I filled the tank with water before welding on it, realistically a new tank isn't alot of money.

Ron

[red69ss]

I found a local guy on craigslist who gets all the returns and displays from harbor frieght and bought a new 40 lb one for $50 .The first one I bought was only $100, so I'm not sure making one is worth the time and risk involved. jmho

[chas350]

I made a pressure sandblaster from a hundred pound propane tank. It works way better than my old siphon blaster.
Because it was used, I filled it with water and let it sit for a couple days and then emptied/refilled before welding.

[1952ssr]

Could you use a air tank instead of a propane tank? Sounds safer!

[ronh72c10]

I've been told that the air tanks are made of a lighter gauge of metal than propane tanks, no idea how you could confirm that. The nice thing about the propane tanks is the relatively large opening on the top, even so it takes a while to fill it.

Ron

[Scott Webster]

How high do you take the pressure to?

[ronh72c10]

I had a regulator that limited it to 80psi.

Ron

[Scott Webster]

Cool. I take my blasting cabinet up to 95 lbs. I was thinking you could get away with less since it pressurises behind the sand too. Thanks