Onboard air, water tanks.

[gwbuild]

I installed an onboard air system in my van and found some nice tanks to use.
They're 9" x 28", they fit perfectly between the outer frame rail and body and sit just about flush with the bottom body pinch weld, they're about 8 gal.
The tanks are brand new with five 1/2" fitting locations, 2 on one end 3 on the other, you'll need to figure your own mounts.

They are stamped 150 psi working pressure but I've had 200 psi in mine since I put it together.

I'm installing another one to use as a water tank that will be pressurized by the air system.
That leaves me with eight to get rid of. $40.00 each

[BrianW]

Are you using it for drinking water? I assume just for showers and the like?

Nice-looking install, although I’d be worried a bit about that valve hanging down and getting ripped off by road debris or something.

[arctictraveller]

Nice looking tanks, but I'd hesitate to put water in them if they are mild steel like they appear to be. If they are lined, or some other material that's a different story. I also wonder why you need 200psi? I'm sure the risk is minimal, but running above the rated pressure could be dangerous in the long run, as the inevitable water that gets in from condensation will sit in the bottom of the tank. Any pressure in the tank will accelerate the corrosion started by the water. The higher the pressure, the faster the corrosion. I've lost two air compressor tanks due to that corrosion from the inside, one just formed a small pinhole, the other failed rather suddenly. The lesson was to drain the tank prior to and after every use.

[gwbuild]

I'm sealing the inside of the water tank, the material is similar to the gas tank sealer but for potable water.
With 200 psi your obviously putting a lot more air into the same space, and with the small onboard compressors it's nice to have the additional air. It takes quite a bit of air when you have four 295/70 tires at 20 psi and need to bring them up to hwy pressure
Any air compressor with a tank has to have the tank drained, depending on use
sometimes daily.

[86Scotty]

Wish I were closer. That is an excellent OBA tank.

[surf92lb]

Willing to ship? Zip 59715 business address?

[arctictraveller]

Originally Posted by gwbuild

I'm sealing the inside of the water tank, the material is similar to the gas tank sealer but for potable water.
With 200 psi your obviously putting a lot more air into the same space, and with the small onboard compressors it's nice to have the additional air. It takes quite a bit of air when you have four 295/70 tires at 20 psi and need to bring them up to hwy pressure
Any air compressor with a tank has to have the tank drained, depending on use
sometimes daily.

All very true. Nice instillation by the way.

[gwbuild]

Originally Posted by arctictraveller

All very true. Nice instillation by the way.

Thanks, it ended up being a nice fit.
Trying to decide if I should mount the water tank on a roof rack, the water may be warmed by the sun?
I'll ship them if I have to but I'm going to wait a week or so, I already have to much time into these.

[1der]

Nice tanks and a great price.

Re: roof mounted water tank and solar heating - not recommended.

Water storage on roof - 40 to 64 lbs of sloshing water will be felt. The water “pressure” will be gravity feed, filling the roof mounted tank is a pita.

Re heating via solar on the black painted tank - when the tank is 100% full and stationary you will heat up the water in the top 10% the tank, the bottom will not heat without introducing some circulation which will only make it take longer to heat water as it will now be exposed to the colder bottom of the tank which is pretty much ambient as it is in the shade.

Cold water sinks (or stays at the bottom of a vessel if heat is applied to the top) - I found this out with a PV solar panel fed electric element water heater I made up - literally (once) had steam at the top of a tank (and at the faucet) and luke warm at the bottom of the tank (took temperature with an infrared thermometer) and that was in a four gallon horizontal tank. This happened because the heating element was in the top 30% of the tank. Took a while (I am a wanna be engineer) to figure out what was going on when the 150 deg set thermostat would click off and the water coming out the tap would not be expected the hot. I repositioned the heating element to the bottom 30% which now created convection currents in the tank and it now works great ( as does the pressure release system which saved my van from a water heater explosion when it went to steam that one time)

I have found the best solar hot water heaters for the roof or rear box are the solar bag style water heaters which can get to scorching temps if left out all day. Easily filled and easy to place on the roof or hang from a ladder or tree and gravity is the water flow. But as far as black metal tanks on the roof for hot water - nope.

If you want your own proof, set one of your black tanks up on a couple of saw horses. Have your fill at the top and supply at the bottom. Try it with a 100% full and another time that is half full. I think you will find what I am describing.

Still wish I had a use hot one of those tanks!!

[1der]

FYI - I am heading from San Francisco to SoCal on back May 10 to 13 if anyone needs a tank transported back up north.