Pressure sandblaster from propane tank

[marblearch]

Hi, if anyone is so stupid as to see the posts and think "Hey I can do that too" who's gonna hold his/her hand the next time they cross the road. The whole point of posting your projects is to show the World what YOU have done, not suggest that that is the way to go about it. The point also is if you hydraulic test to 1-1/2 times the working pressure you are sure the job is sound. The point someone made about the container wearing away inside due to sand abrasion is probably not valid as the sand or abrasive material is just sitting there and not actively blasting the interior like the nozzle would get, and that applies to commercial tanks too that are made from the same thin metal as a propane tank, only they have a name attached to say it was made by whoever and tested hydraulically on such and such a date. If the hydro test fails due to poor welds, the water will only spurt out briefly. Ian.

[Bearston]

Bump

[aametalmaster]

[COLOR="#0000CD"] When it comes to my workmanship and my blaster design You sir don't know what your talking about. Simple as that!

Wildfire.
Its not that simple. You have great pics and do wonderfull work for sure but please remember this is a public forum and some people aren't as gifted in the real welding world and think just because they have seen it here that they can do it. Maybe they can and maybe they shouldn't but its the internet and it has to be true, in some peoples eyes. I have seen air tanks come apart with just 100 lbs of air as it was my fathers just as he was done filling it with only 100 lbs, set it down and picked it back up and it blew. 6 weeks in the hospital and i will never forget that. Just my thoughts...Bob

[Cgotto6]

Wow. Such ignorance, only 100psi, haha. People have no idea how quickly things can go from fine to terrible.

[wildfire]

Wow. It's been a loooong time since I've been here. Anyway. That blaster of mine has been used now for ten years or more. The only thing I've ever replace on it was the main hose. It's longevity has to speak for itself but its been flawless so just because I built it out of a propane tank do not mean its going to fail or be dangerous to operate. I have many safety features built into it such as a safety pressure relief valve and a dump valve.
This unit has hundreds of hours on it and its as good as the day it was built. Everything in my collection and including my commercial work has been done with this unit. You got to be kidding when you say this unit is dangerous. The unit only handles 100psi of air. If the side came out of it the only thing would happen is it would put sand into the air.
When it comes to my workmanship and my blaster design You sir don't know what your talking about. Simple as that!

http://www.flickr.com/photos/15602393@N05/sets/72157608396649530/

Wildfire
just because you got it into print does NOT make it a good idea!!!

modifying a pressure vessel without the proper engineering or hydrostatic test is not a good practice... it is downright dangerous and ill advised.....
Sandblasters are particularly dangerous because the sand/abrasive will erode the inside surfaces as it is being used leaving the outside visually fine...

The outside may look perfect but the inside may get worn paper thin over time... leaving it primed for a catastrophic and deadly rupture at any time....

This is especially dangerous for beginners who;s skills are lacking and who look to more experienced members for sound advice...

This is a Very DANGEROUS practice... use some common sense and do NOT do it...!!

[Sberry]

You probably wont like mine then.

[aametalmaster]

I weld pressure tanks almost everyday at work then they get hydroed or tested with air. I treat each one with respect that i test with air. Anything could happen and each one is looked at before i add the air. No hurrys. The next 4 tanks i am building are 26 feet long and 20" in dia. I only test them to 30 psi and then a dish soap water test on the fittings but thats a lotta air. We pressure tested gasoline barges on the Ohio River with 2# of air and it takes a while to fill them up to find leaks. A guy showed me how a 1/2# that was left in the barge and if you pounded the hatch open with a hammer it had so much force it would break your leg if it hit you, 1/2#. It opened my eyes to really pay attention...Bob

[slanwar]

It is just a bad idea!!!... over time the sand will erode the inside of the tank and fittings..(rather quickly)..... they will get thinner over time... at some point it might look perfect on the outside... while the inside is paper thin.... and will rupture at some point.... why endanger yourself or anybody else in the vicinity???.....

it is a pressure vessel that self degrades with use...

looks like darwin award material to me.... just do not take anyone with you....

how many times must this be pointed out???

I do use black beauty abrasive and I don't use that much or I would buy something big but even the ones we buy would erode after heavy use. For safety every year we should test again the tank with the pressure washer, doesn't take that much time.

[H80N]

It is just a bad idea!!!... over time the sand will erode the inside of the tank and fittings..(rather quickly)..... they will get thinner over time... at some point it might look perfect on the outside... while the inside is paper thin.... and will rupture at some point.... why endanger yourself or anybody else in the vicinity???.....

it is a pressure vessel that self degrades with use...

looks like darwin award material to me.... just do not take anyone with you....

how many times must this be pointed out???

[slanwar]

A year ago I built a sandblaster with a propane tank but I did tested the tank before using with air. Filled the tank with water, making sure no air's inside and then I used my pressure washer at 50% more than the rating of the tank. I did had my propane tank inside a container full of water but I was told later on that I didn't had to. I kept the same pressure for about 10-15 minutes and no leaks.

[slanwar]

Propane tanks are rated at 350psi and they have a escape valve set at 250psi (Propane requires 177psi of pressure to stay liquid). If the propane tanks couldn't handle the 125psi set on that sandblaster then I could say a lot people would be dead by now.

[H80N]

Danger......

I've built a few pressure blasters out of big propain tanks. Here's an article on one of them.

http://gwd.weldingmag.com/mag/gwd_24556/

Wildfire
just because you got it into print does NOT make it a good idea!!!

modifying a pressure vessel without the proper engineering or hydrostatic test is not a good practice... it is downright dangerous and ill advised.....
Sandblasters are particularly dangerous because the sand/abrasive will erode the inside surfaces as it is being used leaving the outside visually fine...

The outside may look perfect but the inside may get worn paper thin over time... leaving it primed for a catastrophic and deadly rupture at any time....

This is especially dangerous for beginners who;s skills are lacking and who look to more experienced members for sound advice...

This is a Very DANGEROUS practice... use some common sense and do NOT do it...!!

[wildfire]

I've built a few pressure blasters out of big propain tanks. Here's an article on one of them.

http://gwd.weldingmag.com/mag/gwd_24556/

[Joe from N.Y.]

I have edited my original post to discourage anyone who might be foolish enough to attempt this. See the first post for details. Thanks to all for either the encouragement, or the admonishment. I appreciated both.

[1930case]

Old large propane tanks are best used for pig cookers, not continued as pressure vessels.

If you can't afford a properly engineered pressure vessel you don't need a pressure vessel. Find a way to fix the money problem instead. Pig cookers sell for good money by the way.

This thread deserves revival as a reminder not to do hideously stupid projects.

I don't really care much if a builder injures themselves by such deliberately negligent acts, but if a vessel goes "boom" and turns someone's kid into a spray of teeth, hair and eyeballs that isn't cool at all.

"Sorry about yer dead curtain climber, but I needed to sandblast some junk. She was kinda homely anyway and you are still young enough to squirt out a replacement" probably won't go over well.