Small fire extinguisher Sand blaster

[MRunknown]

Hello everyone, new to this forum.

I decided to make a sand blaster a few days ago and fiddled all day trying to make a siphon and gravity fed sand blaster... i concluded they are too annoying to make and wont ever be as good as a pressure pot type sand blaster.

So now i decided to make a type of hybrid... a small pressure pot that is constantly being refilled from our main big compressor. have a look at the image i quickly made to explain.

(click it so you can read it)

Do you think it will work?

Thanks!
MRunknown.

[mr95gst]

What if you got rid of the "homemade hollow bolt connection" and Tee'd the hollow tube off the air inlet? That would keep you from having to put another hole in the tank. Might make it hard to repeatable fill with sand though.

If you have not seen it already, checkout the video called "Sandcarving pressure pot-101" on youtube. It has a lot of information. What was particularly interesting is how sometimes you might want different pressures in the media tank vs the feed line.

[kbalch]

Thanks MRunknown! I've added your Sandblaster to our Media Blasting category, as well as to your builder page: MRunknown's Homemade Tools. Your receipt:

Sandblaster by MRunknown

tags: sandblaster

[MRunknown]

Thanks MRunknown! I've added your Sandblaster to our Media Blasting category, as well as to your builder page: MRunknown's Homemade Tools. Your receipt:

Wow! great! thanks very much for that! I made it yesterday slightly differently with a pressure gauge at the "T" intersection. It seems to work quite well, i will test it again today, I learnt something important about putting threads in fire extinguisher tanks - you cant, they are only about 1.5 mm thick and the threads will quickly get ruined. so to solve this, i had to make a very narrow 1/4 inch nut that could fit down the bottle neck and down to the bottom with a socket wrench. now it will never get shredded again. also, i didn't use a tube for the exit, i just used the hose barb on its own. yesterday i only tested it up to about 90 psi and it seemed to work well (but i have never used a shop-bought sand blaster so i couldn't compare it to anything) now that its all air tight i will test it to 150 psi.

What if you got rid of the "homemade hollow bolt connection" and Tee'd the hollow tube off the air inlet? That would keep you from having to put another hole in the tank. Might make it hard to repeatable fill with sand though.

If you have not seen it already, checkout the video called "Sandcarving pressure pot-101" on youtube. It has a lot of information. What was particularly interesting is how sometimes you might want different pressures in the media tank vs the feed line.

Thanks for the ideas, i thought of that, but i didn't have a "T" hose barb intersection to use, and i wanted to buy as little things as possible (because that means convincing parents and compressor fittings are pretty expensive around here). the only part i bought was the inside threaded hose barb for the exit.

I'll have a look at that Video, I like the idea of different pressures, but that's pretty complicated if you think about it, that means either 2 compressors or 2 pressure regulators, and i wanted this to be a nice and simple thing that works reasonably well.

NOTE: This was designed by a 14 year old (me)! if you build it, use it at your own risk!

Thanks for your ideas! i don't have the resources at the moment to do them, but someone else might!

Thanks.
MRunknown

[MRunknown]

I tested it again today. Its is pretty good, but needs improvement. it does not put out enough sand, after watching that video mr95gst suggested, i worked out why: my air valve down the bottom needs to be reversed, put on the other side on the 'T' before the sand valve, so that when you close the air valve slightly, pressure increases in the sand chamber, and more sand is pushed out.

So i will try and work that out today and tell you if it is better!

Thanks.
MRunknown.

[mr95gst]

150 PSI? Typically sandblasters run between 70 and 90 psi. Please be careful. Pressure vessels (pressurized tanks) scare me a bit because if they are not done right they become bombs. The tank you are using might have been rated for much higher pressures, but that rating would become null and void it you punched any holes in it.

[Bill Dancliff]

I have the propane style tank used for sand blasting and have spent many hours trying to get consistent results without success. I have installed a vertical pipe cross drilled to slow the feed rate of the sand in addition to the ball valve and it still gets plugged and stops the sand. One solution I have read about is to use a very good American made air drier on the incoming air to eliminate any moisture to allow the sand to clump and clog the output, the other solution is to add a mixing valve to the bottom of the tank and these are used in all professional sand blasters. But they are very expensive starting at $200 and jump to $400 and on up. I have given up but hope you have better luck. I believe a pressure washer with a siphon feed is the most economical and safer for your lungs. Good luck and invent a solution.

[MRunknown]

I have the propane style tank used for sand blasting and have spent many hours trying to get consistent results without success. I have installed a vertical pipe cross drilled to slow the feed rate of the sand in addition to the ball valve and it still gets plugged and stops the sand. One solution I have read about is to use a very good American made air drier on the incoming air to eliminate any moisture to allow the sand to clump and clog the output, the other solution is to add a mixing valve to the bottom of the tank and these are used in all professional sand blasters. But they are very expensive starting at $200 and jump to $400 and on up. I have given up but hope you have better luck. I believe a pressure washer with a siphon feed is the most economical and safer for your lungs. Good luck and invent a solution.

Thanks, our compressor already has a water separator, and my blaster doesn't clog, but rather it is too slow, its pretty good for small jobs, but too slow for large things. i will try putting a bigger tip on mine, if i cant get it much better i might try using a pressure sprayer setup like you mentioned.

Thanks.
MRunknown.

[Bill Dancliff]

It sounds to me that it is too slow because you have restricted the amount of sand with the ball valve, and if you open the valve to allow more sand it will clog. My experience when I opened the ball valve to allow a more efficient amount of sand to flow, it would clog the tip. With my compressor I can push 150lbs but still cannot stop the clogging. I have tried baking soda and have no flow problems. One more idea I read about is to fasten a vibrator to the bottom of the tank.

[C-Bag]

I hope I haven't missed something, but wouldn't it have been better to have the tank upside down to take advantage of rounded dome of the top to help funnel more sand flow into the blast tube?