I like the fire extenguiser idea, i have a couple of them kicking around. I have both kinds. ones that kind be refilled with water and the chemical ones. can any one give me a brief description on how they turned it into a holding tank?
i like the pvc pipe idea.. i have seen it done for under the hood, it was much smaller.. like 4" by 2' or so.. so im sure it didnt hold a ton of air. but i would like something to hold about 3 gallons or so... any thoughts about this pvc thing?
PVC works fine......it's just subject the external insult.....and when it fails it goes "boom". One of my many $hithole careers was at place that used PVC to supply air throughout the place (this is the only place I've ever seen it used for this)......it would blow out someplace or another and the place would shut down for a while until the maintenance man glued in another piece and let it set for a while. We use 3" and 4" CPVC at work for some transferlines .......all the "plastics" have a pressure @ temp rating. Once you exceed the temp rating of the material......you're kinda on your own figuring out the pressure integrity of it.......it just doesn't have a linear fatague progression.
Figures don't lie ....... but liars sure do figure.
I don't know about the PVC you can get at the local Home Despot, but the stuff I throw in the ground for waterlines (C-900) would definitly work for an air tank. The walls are about 1/2" thick on the small stuff, thicker as the pipe gets bigger. It might be available in 4" but I've never seen it. I have installed 6" and up. Best part is, when I do a water job, we're always throwing away pieces 3-5 ft long. Any waterline construction going on around you, ask one of the guys for a scrap. As for end caps you would have to go with Home Despot stuff, all the stuff we use to cap lines is ductile iron and it gets kinda pricey. The heavy sidewalls would be a great advantage if the "tank" ever took a hit off roading. I've hit the stuff with excavators and seen it survive.
Sorry, can't help anyone out at the moment. I'm not doing water right now. But if ya need some 90" RCP (reinforced concrete pipe) I can hook you up.
a little off-topic, but it relates. i was looking at potato gun websites to design for an engineering class a ping pong ball launcher using compressed air. All of the sites mentioned a high risk factor with the pvc due to it being so brittle. 300 psi as mentioned earlier is too high for standard pvc, i think its max should be 125 for safety. when it blows though, it shatters like glass, might not matter if it is under the jeep, but anywhere else and millions of flying plastic shards are gonna do some damage. ABS pipe i think is not so brittle and a little stronger, but again, i am not sure it would be that safe. be warned, i would hate to see jeepers running around with chunks of plastic imbedded in them. kinda follows the welding on a gas tank rule. i suppose it can be done, and someone will be the first... it just wont be me.
Andy, Here's how I made my tank from an old fire extinguisher. I used a standard chemical extinguisher not those that can be refilled. I took off the dispensing mechanism that screws on top of the bottle and cleaned the bottle well. Then I went to the machine shop and had them machine an adapter that screws into the bottle on one end and gives me a 1/4" connection on the other. I then connected my new tank using a short air hose to the manifold that's built into the pressure switch and I installed the pressure relief valve in the manifold. It works very well. Note that with this setup you will not have a drain valve so every once in a while you'll have to unhook the tank and empty it. depending on the weather where you live you might have to do that once a year or once a month.
Hope this helps. Feel free to ask me for any more details.
The big problem with the PVC tanks is that they don't dent, they explode. There was a big discussion about using PVC to run air lines in shops on a farmer BBS I'm on, and several guys relayed stories about exploding PVC. When it's being used for sewer/etc and isn't under pressure, if you hit it, all it's strength is resisting the breakage. Even if you do break it, it will only crack then. But when you put lots of pressure on it, a great deal of its strength is being used to fight the pressure and not explode without external force. When it gets whacked while under pressure, instead of denting, cracking or rupturing like a steel tank would, it explodes into little pieces. I don't really know all the specifics behind it, it's kind of another one of those things that sound like a really good idea...until you hear about the guy who did it and suffered. On it's own, the PVC apparently worked great and didn't rust...but if something hit the pvc while it was pressurized...boom. When I get around to the Onboard air, I'm going to skip the PVC...
Trying to come up with a witty line to end all of my posts...
I use a Scuba tank picked up at the flea market for 10 bucks. I'm a diver. The tanks are rated at 3500 PSI. The Extreme challange guys use them in a magazine article I read to run 1/2 in impacts for tire changes. The first stage regulator cuts the pressure down to a manageable 125 psi. The older stuff is cheap as this is a life support device and no one screws around too much with the old stuff so the demand is not there. You can use it everyday as a reservoir with a YORK to 150 PSI or run it into a SCUBA/Dive shop and get it filled to 3500PSI for about 3 bucks.
My 2 cents
Lenny in Colorado Springs
67 Jeepster 225 V6 & 3 speed
96 Dodge Ram 2500 V10 AT CC LB 4x4
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