Propane expectations...

kansassky · #1 2012-09-16, 1:51pm

I have been exchanging my 5 gallon propane tanks at Walmart.
Blue Rhino brand. Take in the empty, exhange, and walk away with a full tank. I pay $17.82 for an exchange. Easy-peasy.
However, I have no idea if I am getting a full tank.

This last tank didn't seem to last long.
Which got me to thinking...

1. Has anyone here ever kept a log to determine the avg. number of hours a propane tank will last? I am using a minor with a M20 concentrator.

2. I know cylinder tare weight is stamped on the outside. (At the farm implement place where I USED to buy propane, they would weigh the new tank in front of you when you purchased it, so you could verify that it was full.) Is there any way to be proactive at Walmart? Or, am I a consumer hostage/victim of the system?

Curly Irish Girl · #2 2012-09-16, 2:07pm

I just saw a gadget you can put on a BBQ line that will give you a dial read for amount of gas in tank....don't see why it wouldn't work on a torch set up. Our Weber grill has a button to push that weights the remaining gas in tank..

Alaska · #3 2012-09-16, 2:33pm

As I recall for a Cricket it is 23 hours of torch timer per gallon of propane. Of course, one must remember that there are a whole batch of variables that enter into any usage rate. As usage for one person may be vastly different for another lampworker.

It is also possible that your lampworking techniques have changed and now require more fuel or the tank was short. Have filled up owned propane tanks at the Holiday station where there is no question as to how much fuel was purchased.

To make sure weight and do the math to determine how much was purchased.

losthelm · #4 2012-09-16, 4:48pm

You can try measuring the tank by feel or simply buy your tank early in the morning.
There is a condensation line that will show the level of liquid propane.
In my experiance pressure gauges don't work well with propane.
The pressure won't drop untill the liquid stops the phase change frome liquid to gas.
Luckily with larger tanks you still have a bit of burn time before the pressure drops.
A spare tank can help a bit.
The tanks also hold a bit less with the new valves, they also have a bit more head space.

I shop areound for the best price and found one place that charges 15. To refill.

Good luck

Roo Blaty · #5 2012-09-16, 4:50pm

I weigh mine when I get it back home...

Dragonharper · #6 2012-09-16, 5:29pm

Depends on the size of your torch and the size of your flame. I'm running a Bravo and I've given up counting propane hours. Oxy is about 8-12 working boro. I don't think I've swapped LP tanks since April, and I torch on average 4-8 hours a week. 120 CuFt of oxy lasts about 8-16 hours depending.

squid · #7 2012-09-16, 5:45pm

Blue Rhino refills are 15 lbs in a tank that will hold 20, so no, you are not getting a full tank.

Dale M. · #8 2012-09-16, 5:49pm

There is two fool proof ways to tell how much fuel is in your tank at any given time....

First....

Propane weighs 4.25 pounds per gallon.... Full propane tank (BBQ Style) holds about 4.7 gallons.... That is approximately 19.97 pounds of propane....

Find tare weight of tank, it will usually be something like 18.8 to 22.5 pounds and will probably be shown as "TARE WT XX.X" this weight is for the empty tank.... Tare Weight should be stamped on tank safety collar...

Put tank on bathroom scales and get reading, subtract tare weight from value show on scales, the results will the the weight of propane in tank, also divide the resulting weight by 4.25 and it will give you the gallons of propane in tank....

Second...

Take a 2-3 quart pan and fill it with water, and bring it to a boil on stove... Once water is hot take it out to where tank is and slowly dribble it down side of tank.... Once water is all gone, slide the palm of your hand down side of tank... Where you find a line where the steel of the tank changes from warm to cold is the line of where liquid propane is in tank... Anything below line (cool area) is volume of liquid fuel in tank...

Most other methods are noting but a cruel joke and accuracy is really questionable... Pressure gauges lie... They will show full till tank almost totally empty because tank pressure is a product of temperature.......

Dale

Dale M. · #9 2012-09-16, 5:51pm

Quote:

Originally Posted by squid

Blue Rhino refills are 15 lbs in a tank that will hold 20, so no, you are not getting a full tank.

As price per gallon of propane goes up... Volume goes down so price per tank remains a constant (usually) ...

Wal-mart and most other exchange places are just a "agent" that collects monies for a percentage and propane and volumes and what ever are actually controlled by the company supplying the propane ( BlueRino or whom ever) ....

Best deal around is take tanks to where they actually fill them locally while you watch...

Dale

squid · #10 2012-09-16, 5:56pm

Quote:

Originally Posted by Dale M.

As price per gallon of propane goes up... Volume goes down so price per tank remains a constant (usually) ...

Dale

Yep!

kansassky · #11 2012-09-17, 8:55am

These are all good tips! I was aware that a "full tank" is not really full. What I should have said is at "full capacity."

In my former life, as a hot-air balloon pilot, we used 10 gallon or 20 gallon LPG tanks. We had to fill them ourselves after each flight at an outdoor facility. We attached the bulk tank tank hose to the small tank, opened the bleeder valve on the small tank, and turned on fill until the bleeder valve began to spit slightly. That ensured a good fill. The bulk tank had a meter just like a gasoline pump, so we never had to really question how much fuel we got or purchased.

Guess it just makes me skeptical to engage in blind trust on this whole "filled tank" issue.

Again, thanks for all of your input. I am going to weigh my newly purchased tank. But, I know I still can't return it if it isn't at capacity. Guess I could take my scale with me to Walmart. That guy with the propane cage key would think I'm a nut case.

Dix

Alaska · #12 2012-09-17, 1:45pm

Quote:

Originally Posted by kansassky

Guess I could take my scale with me to Walmart. That guy with the propane cage key would think I'm a nut case.

Would just say that you were a wise shopper that expects value for their dollar!

Seems that the bottom line is to own your tank and fill at the least costly propane filling station.

LarryC · #13 2012-09-17, 3:45pm

Quote:

Originally Posted by Alaska

Would just say that you were a wise shopper that expects value for their dollar!

Seems that the bottom line is to own your tank and fill at the least costly propane filling station.

Blue Rhino is very expensive. I fill my tanks at a gas station which charges $15.00. Local Blue Rhino drop offs charge as much as $26.00 to exchange a tank. I like keeping my own tanks and being able to watch as my tank is being filled. Keeps everyone honest.

houptdavid · #14 2012-09-17, 4:26pm

Only use Blue Rhino (*Amerigas or other exchanges) when your tanks EXPIRE! Make sure you don't get their "special" refillable by Blue Rhino only tanks.

I get mine filled at the local gas station and it's around $15 for a FULL tank

SerendipityArtGlass · #15 2012-09-18, 12:36am

FWIW, my DH has written on the side of my BBQ tanks "FULL=40lbs"

losthelm · #16 2012-09-18, 5:47am

Your local fuel company or welding supply should have the fittings so you can use larger tanks on your torch, a bit more clumbersome for show and demos but you all ready have the larger tanks. A 30 gallon tank should last for quite a while.

Moth · #17 2012-09-19, 7:58am

I agree with Dale, as usual, own your tank and get it filled while you watch.

They set mine on a scale while it fills and I watch it tip. Costs me about $19 now...used to be $17.

Lasts me about 3 months depending on how hard I'm working. 20# bbq style tank.

~~Mary

cheng076 · #18 2012-09-19, 11:05am

Just filled 3 tanks yesterday. $2.99 per gallon at the local feed store; cheapest in the area and closest too. I have one tank I will have to get recertified before I can fill it again and get 5 more years out of it. I would never not own my propane or oxy tanks.