Another dumb compressor idea form Bjorn.

[Bmxin^Bjorn]

Kay guys , heres another idea i have with compressed air. I dont have any money to buy a new air compressor cz i'm buying a new jeep, but i have a 6.5hp motor from my go-cart and was thinking could i just get one of those air compressor pumps from princess auto and build an air tank. I want the tank to be about 240 gallons, how thick would the pipe have to be?,, i figure i need about a 2 1/2' o.d. pipe ,, but how am i going to cap the ends? and what kind of valve do i need to stop the compressor when the tank is full?

[SkidSteerSteve]

I'm going to completely stay away from advice on a tank fab job of that size....At 2.5' diam/120psi that works out to 84,780 lbs of force against each end (or 169,560lbs between the two).

As for the motor controls, though. Your best bet is to just get an unloader valve that is designed for motor driven compressors. It is a combination unloader valve and idle control mechanism. When a predetermine pressure is reached, a cable connected to the carb throttle drops it back to idle, and it vents the compression back to the atmosphere and a check valve seals the tank. They never really shut off, they just redirect. SSS

[Bmxin^Bjorn]

Thanks for the valve advice dude.. how did u figure out the pounds of pressure on the ends??..

i'm going to do this anyways guys so dont try to convince me not to ..

[Bob the Welder]

Hope you have good insurance, both liability and life!

[Goodhand]

Curious about how one goes about fabricating the spherical ends of an air tank.

[Bmxin^Bjorn]

i was planning just to cap it with plate and drill holes in it and run a rod through it to beef it up

[TomVeatch]

... how did u figure out the pounds of pressure on the ends??...

Pounds per square inch X number of square inches (3.1416 X R^2)

[glockdoc]

As for the motor controls, though. Your best bet is to just get an unloader valve that is designed for motor driven compressors. It is a combination unloader valve and idle control mechanism

Where's a good source for one of these?

[Bmxin^Bjorn]

pincess auto has stuff like that.. Should i mig weld it or tig?? any ideas?

[makeithot]

Air tanks

You can buy air tanks pre-made for a lot less trouble then building them. Spherical ends can also be bought.

[Pitalplace]

My guess is you can buy a new or used compressor cheaper than you can build one. And a lot safer.

[croyall]

How long will it be?

I haven't taken the time to calculate the length but I figure that a 2 1/2" pipe would have to be really long to get a 250 gallon tank. I'm just thinking I have a stand up compressor with a 60 gallon tank and it is 22" diameter.
Just a thought.

[croyall]

My mistake. OOPs

I just re read your initial post and saw it was 2 1/2' not inch.

[KEENAVV]

I went back to look for your location but it is not listed. Isure hope your not building that BOMB near me !!!

[jamlit]

I would not recommend building an air tank. You would be much better off buying a used tank or waiting for a sale on new ones. Their are laws in Canada which prohib none certified welders from welding pressure vessels and their are very serious fines. Caping the ends to me show me that the idea is not sound as welded convex caps would be the preferred choice.

I know that it seems easy to weld up some material and use it for an air tank but I can't stress the fact that it is ilegal.