ecchamberlin

I just found this on ebay
http://cgi.ebay.com/ebaymotors/Ultim...48302030QQrdZ1

This is really cheap for a system compared to other more well know vendors.

It is my opinion that they are using this tank.
http://cgi.ebay.com/10-lb-Co2-Tank-K...QQcmdZViewItem

If the beverage tanks are not safe then this would be a real issue right?

mt_goat

That's the key, with the CO2 you can liquify it under lower pressure and get much more volume into the tank.

mt_goat

I found a used 20 lb alumunim CO2 tank at a refill place and they fit it with a used regulator. I made the bracket and stuck a handle on it with hose clamps. I think I have less than $150 in the set-up:

AH64ID

But what is the volume possibility? A 130 cuft scuba tank holds the same as a 20lb CO2, and they are about the same size.

Corey

iTrader: (1)

This debate over scuba and C02 tanks has been going on for years.
Bottom line is a scuba tanks can not fill over 30 tires like a 10 lb C02 tank can.

Also a scuba tank if the reg gets knocked off it is a deadly missile since it is under so much pressure.

mt_goat

But the problem is you can't liquify air at a safe pressure. You can sqeeze in many more molecules in the liquid state than the gas state.

AH64ID

Yes I understand both of those. I was just curious thats all, a scuba tank does hold a ton of air, but not as safely, which from looking at the numbers is the big bonus to CO2. I am not interested in either, just adding to the useless knowledge bank

Tofer

where did wabbits post go? i saw he posted, but didnt have time to read the whole thing.. this is exactly what i am thinking of building



where would i go to get the tank pressure tested

waskillywabbit

iTrader: (-1)

I deleted it cause everyone already knows it all and I'm tired of wasting typing for no one to listen. If you really want to know, email me.

mt_goat

Any place that fills them should also test them.

slosurfer

I really did want to know if the tanks were made different. You were the first person to say anything about the tanks not being made for offroad but a "powertank" is. I thought your post was very informative and it spawned some questions. People asking questions does not imply that they are not listening to you, in fact it implies that they listened and have more questions. I respect you and you have a good background in this area which your post proved. I just wanted to know more because I wheel with my family and I have a co2 tank, and you brought some doubt into my mind about the safety of it.

ecchamberlin

I found this very intersting from Power Tank's site.

Isn't a CO2 tank like a potential rocket on my vehicle? - No. Because CO2 is stored in a liquid form by nature it releases its energy differently than other "compressed vapor" gases such as nitrogen, oxygen, acetylene, or scuba tanks. With a compressed vapor like N2 and scuba the full amount of its stored energy in a tank is ready to be expelled all at once. That is why cylinders of these types of gases will "fly" in the case of a knocked off valve. In order for liquid CO2 to release its stored energy as a compressed vapor it must go through a phase change from liquid to vapor (essentially evaporate) through the absorption of ambient heat energy. This process limits the release speed of its compressed energy. This is how a person of small stature can hold a CO2 fire extinguisher in his/her bare hands and literally open the valve wide open while pointing the horn (nozzle) at the fire without getting blown backwards.

How Safe is it? - The components of the POWER TANK™ are all heavy duty and built for safety. The service pressure rating of our 6061-T6 aluminum cylinder is 1800 p.s.i. with a maximum pressure rating of 3000+ p.s.i. although the normal cylinder pressure range for CO2 is only 700 to 800 p.s.i.. There is also a safety "pop-off" valve built into the main valve set to release pressure if it ever reached 3000 p.s.i. (i.e. fire or accidental overfill). Our cylinders are brand new and are DOT Approved. The adjustable regulator limits the maximum outlet pressure to 200 p.s.i. Finally, the handle at the top doubles as a guard protecting the regulator and valve from getting knocked and damaged. It is made of solid 6061-T6 rod tig welded to a billet aluminum clamp and secured to the cylinder with 3/8" stainless steel bolts. Naturally, whenever handling high pressure equipment, precautions and common sense must be practiced.

It makes a lot of sense to me.

mt_goat

I want to hear from the Wabbit too!

On my tank (since it is aluminum) I was careful to put rubber padding around it anywhere the steel bracket touches it. The refill place guy told me he sometimes refuses to pressure test a tank if it has a lot of wear and tear.

chadbobb

I scuba dive and play paintball (and now starting to wheel- not a good combination money wise for a high schoool student haha- that aside)
To compare compressed air to CO 2 I will use paintball guns.

I originally used CO 2 in my paintball guns. I used a 20 oz CO 2 tank which was supposed to get around 1350 balls per tank. So 20 oz CO 2 ~ 1350

I then switch to a 114 CI (huge tank) at 3000 PSI and expected 1140 balls per tank.

Now i don't have the exact Cubic Inches for the CO2 tank. But it is a good amount smaller in size, and gets more shots per tank. So there is more gas in the tank. I measure the circumference to be about 10.5 inches, and the length about 8. So 8 * 1.67^2 * 3.14 ~ 70.2 CI excluding the thinkness of the tank.

So
~114 CI compressed air = 1140 paintballs
~70.2 CI CO2 = 1350 balls.

I can write up some conversions later of what you should expect out of a 20lb CO2 tank verses a aluminum 80.... but that will take a while because i need to figure out some stuff. Scuba tanks are rated in size funny. An aluminum 80 is 80 Cubic Feet expanded. So at sea level an aluminum 80 would fill a room 80 cubic feet exactly to 14.6 PSI.

And one last thing for now, a picture of some tanks. An aluminum 80 is the blue one. The next one is a compressed air take 114 CI. The smallest tank is a 20 OZ CO 2 tank.

Scofco

I finally got my setup rigged together, took me about an hour from conception to completion. I have everything except for how I'm going to mount it in the truck. I'll probably have to get something custom done unless someone has an alternative.

Total investment: $18.

$14 for the 25' recoil hose in fashionable yellow.
$4 for the adapter for the tires, I already forget the name of it.

The $110 regulator was free as was the $20 CO2 tank. Perks of the job.

I'll try it out this weekend in the driveway and see how well it works. What I REALLY need now is some damn tire deflators. I'm tired of doing it in -20 weather with a pen Gets too damn cold.

FredTJ

Sigh, everyone makes everything sooo hard here

Get a valve stem core remover (any auto parts store) and a couple of spare cores (you should have both already anyway in you gear/spare bag).
Simply remove the valve stem core and let the air out that way. Piece of cake, really fast, cheap and simple.
With e tire gauge that has a straight end you can even check the pressure with the valve core out.




Fred

AH64ID

Same way I do it... and after a while you can hear when your tires hit a certian pressure.. the flow sounds different... Usually around 13-15psi there is a big change in sound...

CJM

I am even cheaper than buying a vale core removal tool, When you get your tires changed ask them to give you the old valve stem caps. Then push, pound, drill or whatever a hole to fit a finishing nail in it. Instant screw on deflators...

AH64ID

That sounds slow and prone to breakage... maybe you should post a pic.. but a valve stem remover is like .49.. hardly an expence not worth making...

CJM

I have no cam, but its simple, I guess it could break but a buddy of mine campe up with the idea and been using it for a few years now.

Problem with the valve core removal tool is you may wind up shooting the vale way off into space, hopefully you got more though.