Large propane tank for compressor tank??

[Fyrme]

Well my vintage Hercules 80gal compressor finally sprang a leak yesterday. It was probably my fault since I'm not the best at draining the tank on a regular basis. So now I'm on the search for a tank. Like most useful things around here, they are hard to find. But I did find a 83gal propane thank from a automotive fuel system. Would this be a viable option? The price is right, and it has plenty of bungs and as long as it has stayed sealed, moisture should not have been an issue through its life. All I'd have to do is weld on my mount, do minimal plumbing and be done. Would there be a reason not to use it? (Btw, if the is still any Oder of propane, I would fill it with water before welding on it)

 

[Fyrme]

Just spoke to the owner of it which he just happens to [Hank Hill voice]"sell propane and propane accessories[\Hank Hill voice]. He bought it off a kid that had it in his truck, still full of propane. So it is leak free. Thinking about it, the only problem o see is that It probably doesn't have a bung on the bottom to drain it. However, being a LPG tank, it has two valves, one for gas at the top of the tank, and one for liquid at the bottom. So I guess the liquid valve could technically be used as a drain valve.

 

[ilovevocs]

I have never ventured down this road but here are a few of my thoughts.

The "stuff" the name escapees me at the moment, that they utilize to scent the propane is difficult remove from the tank. I have read somewhere about guys attempting to remove it and leave the tank scent free to no avail. Not sayings it impossible, just something to consider.

Further more, I wouldn't weld on the tank. I would mount the pump separate.

Would also verify that the original contents will not have adverse reactions with what ever process your utilizing. Me personally I paint with my compressor and wear a positive pressure mask so it would be a no go.

 

[Muggzy]

if the is still any Oder of propane, I would fill it with water before welding on it)

I did this with a regular old bbq size tank. The smell is added to the propane to make it noticeable when there is a leak. Its not flammable, it is difficult to get rid of though. I used a half bottle of simple green half the tank of water, shook it around some and let our stand over night. Poured out out and did it again a couple of times to finally get rid of the smell.
Kinda hard to do on a tank that big though.




Muggzy - from my phone

 

[porschedude996TT]

The "stuff" the name escapees me at the moment, that they utilize to scent the propane is difficult remove from the tank. I have read somewhere about guys attempting to remove it and leave the tank scent free to no avail. Not sayings it impossible, just something to consider

The scent stuff is called Methionine or Methyl Mercaptan.

 

[stonesfan68]

I do not recommend welding on that tank. Leave the compressor where is it and simply re-pipe the discharge from the cylinder head to the propane tank. You will also need to move the pressure gauge and pressure relief valve from the old tank to the new.

 

[Wood'nMetal]

I used a small LP tank as an air tank in my off-roader. Works just fine, although years later the air still smells like LPG!

I see no reason not to use a big tank or to weld on it. After all, the bungs for the fittings are welded on!

 

[signcrafter]

I'm in the don't weld on it crew. Can you? Probably. But why take the risk of weakening the tank at all when you can just as easily mount the motor and pump above it and plumb to the tank.

 

[AmericanPreferred]

I see no reason for worries provided you completely fill it with water first, and that may not even be needed. Is the rest of the setup available? Propane is less than $2 gal for at least for the next year for me, they say gas is about to soar again. I would be intrested in the kit if its for sale.

 

[aka Larry]

Why would welding weaken the tank? I'm pretty sure my air compressor has welded-in bungs as well as bracketry for the pump. That tank is likely rated for more than double the pressure the OP will be putting into it. Afterall this is a steel tank, not a PVC bomb waiting to explode. Worst case, it leaks.

 

[Fyrme]

I can easily cut the mount off my tank and set it on rubber isolators and build a set of straps to hold it on the tank with no welding. I found a older Cman 60gal working comp that I might buy and put my bigger pump and motor on it. Then sell the other motor and pump to recoup some $. (Waiting on a reply) Or I also found a monster 120gal 3ph that is not working for $100 but I'm afraid my little pump would burn out trying to fill that thing.

 

[EOC_Jason]

I've seen some propane company here locally offering used propane tanks like that for sale as BBQ pits or air tanks... It should be more than adequate to handle the pressure, but like you said the two issues are a drain and the smell.

 

[Fyrme]

Why would welding weaken the tank? I'm pretty sure my air compressor has welded-in bungs as well as bracketry for the pump. That tank is likely rated for more than double the pressure the OP will be putting into it. Afterall this is a steel tank, not a PVC bomb waiting to explode. Worst case, it leaks.

It probably won't. But I think most people's concern is that if the person welding it is not a good welder and burn the weld in too deep, it will weaken it. You must realize, when they build these tanks, all the welding is done then it is pressure tested. Welding on it afterwards, it would need pressure tested again.

 

[Fyrme]

Now that I think of it, I can weld my mounting pad right to the pad that is on the tank already.

 

[BDT/NWMN]

I can easily cut the mount off my tank and set it on rubber isolators and build a set of straps to hold it on the tank with no welding. I found a older Cman 60gal working comp that I might buy and put my bigger pump and motor on it. Then sell the other motor and pump to recoup some $. (Waiting on a reply) Or I also found a monster 120gal 3ph that is not working for $100 but I'm afraid my little pump would burn out trying to fill that thing.

120 gallon tank designed for compressor use,,, $100,,,, that is the winner,,, your"""little pump burning up"""""??? That will not be an issue.... you are gaining storage capacity...A good ++

 

[signcrafter]

Why would welding weaken the tank? I'm pretty sure my air compressor has welded-in bungs as well as bracketry for the pump. That tank is likely rated for more than double the pressure the OP will be putting into it. Afterall this is a steel tank, not a PVC bomb waiting to explode. Worst case, it leaks.

It probably won't. But I think most people's concern is that if the person welding it is not a good welder and burn the weld in too deep, it will weaken it. You must realize, when they build these tanks, all the welding is done then it is pressure tested. Welding on it afterwards, it would need pressure tested again.

Right. I'm not a certified welder but from what I know welding on a pressurized vessel(think that's the proper term) takes some skill to do it right. If you have the skills to do so, knock yourself out. I'm not sure if welding on the tank would weaken it or not. But you are heating up the metal and changing it's properties when you weld on it. Also you are welding a piece of steal on it with a vibrating motor and pump on it. Will that vibration do anything to the tank at the weld? I don't know, I'm not an engineer, but I'm sure these are things taken into consideration by the people that make compressor tanks. My point was why take the chance of compromising the tank? Especially when you don't have to, just mount the motor and pump to something else by the tank and plumb to the tank. I'm not being negative, just looking at all the outcomes, the good and the bad. I'm sure there are a good many guys on here that can weld on a tank all day long. I just know that welding on a tank isn't the same as welding two pieces of angle together to make a table or something.

 

[aka Larry]

I'm sure there are a good many guys on here that can weld on a tank all day long.

OK, have ZTFab do it. If you don't know who that is on this forum, look him up. It's worth it just to see pictures of his work.

 

[Fyrme]

The extra capacity of the 120gal tank will make the motor and pump run longer. I'm not worried about over working the motor, but I would think the pump would get a lot hotter running almost twice as long. Am I wrong?

 

[aka Larry]

The extra capacity of the 120gal tank will make the motor and pump run longer. I'm not worried about over working the motor, but I would think the pump would get a lot hotter running almost twice as long. Am I wrong?

...or you could look at like it would run twice as long but half as often (with the extra capacity)

 

[signcrafter]

The extra capacity of the 120gal tank will make the motor and pump run longer. I'm not worried about over working the motor, but I would think the pump would get a lot hotter running almost twice as long. Am I wrong?

Depending on the motor and pump some of them it's better to run longer. It's the starts and stops that are hard on them. In some big shops the compressors run all day long.

 

[Farmall450]

I see no reason not to use a big tank or to weld on it. After all, the bungs for the fittings are welded on!

At the factory, before it has LP in it!

 

[Fyrme]

Depending on the motor and pump some of them it's better to run longer. It's the starts and stops that are hard on them. In some big shops the compressors run all day long.

Well fwiw, this is my compressor and motor/ pump in question.

The original name plate on the compressor is missing. I don't know any duty ratings etc. except for the calculations I did my self. It is a 80 gal tank. It is set to 140psi and kicks in at 110psi. The motor is a single phase 5hp Baldor wired for 220v. It puts out 16cfm by my calcs. Now, in my situation, this is plenty of air and CFM. Do I need a 120gal tank? No. Could I use it if it was there? Sure. Will it over work my already tired pump? Idk. If I go the LPG tank route, I think I will pour a gallon of oil based paint in the tank and roll it around to coat the inside, pour out the excess, then let it dry for a week in the sun. That should take care of the smell and potential rusting.