Compressed gas can

[Russ]

I have two 12 gallon tanks installed by the dealer. Like these. Not sure the manufacturer.
http://www.amazon.com/Moeller-12-Gallon ... +fuel+tank

I've heard of others having issues with them. Fortunately I haven't had a lick of trouble despite leaving vents closed and collapsing them (as above) and expanding them like a ballon. Maybe I've just been lucky. I agree with the post above. You would expect more quality control over these things that he had so many failures with. From a mere liability standpoint the manufacturer is exposing themselves to lawsuits if some boater blows himself up with a leaky tank.

The 6 gallon tanks seem like they would give you more options. The 12 gal tanks can't be taken out, they are too heavy. Even 6 gal tanks would be heavy also. Mine have fuel gauges, but they are very crude.

Mine have quick release connectors so I can switch tanks at will with the motor running.

--Russ

[dlandersson]

I have the 6 gallon cans with quick release connectors for exactly that reason.

I normally use a 2 gallon gas can to refuel (don't use much, and wind is free) but you CAN pick up and refuel the 6 gallon fuels cans if you wish to.

I have two 12 gallon tanks installed by the dealer. Like these. Not sure the manufacturer.
http://www.amazon.com/Moeller-12-Gallon ... +fuel+tank

I've heard of others having issues with them. Fortunately I haven't had a lick of trouble despite leaving vents closed and collapsing them (as above) and expanding them like a ballon. Maybe I've just been lucky. I agree with the post above. You would expect more quality control over these things that he had so many failures with. From a mere liability standpoint the manufacturer is exposing themselves to lawsuits if some boater blows himself up with a leaky tank.

The 6 gallon tanks seem like they would give you more options. The 12 gal tanks can't be taken out, they are too heavy. Even 6 gal tanks would be heavy also. Mine have fuel gauges, but they are very crude.

Mine have quick release connectors so I can switch tanks at will with the motor running.

--Russ

[WASP18]

I chose six gallon tanks for the simple reason of weight. I can't imagine lifting (2) twelve gallon tanks out of the boat to refuel. (Six lbs to a gallon plus the weight of the tank)That's 80 pounds or so each when considering the empty tanks are also on the heavy side.

[WASP18]

ok, so I left the air valve open last night during the lower temps, then this morning closed the air valve and put it in the sun.

Hmmmm.


Amazing!!!

What are these things made of?!

So its about a 6.5 gallon tank now.. Properly set back in its place with the air valve OPEN this time.

If I understand this correctly, the final solution was to open the air valve at night to capture the cool air. The next day, place the tank in the hot sun 80-90 degrees F with the valve closed and the expanding internal air will expand the tank back to a normal shape. The hot water was another alternative but the cold night/hot day was quicker and more effective?

[seahouse]

OK- I just did a quick calculation to get right what’s really happening here. The Ideal Gas Law (the Certified Divers on this forum will be familiar with this formula; PV=nRT) gives an increase in volume of less than 5% (in air)over the temperature range we’re dealing with. So it's not the expansion of the internal air that's mostly at work here.

It’s the vapour pressure of the gas that’s responsible for most of the change in volume (and hence the pressure - Boyle's Law) that takes place in the tank with temperature. This conforms with observation, because you don’t see this kind of expansion in an empty (air or water-filled) sealed container.

Also, less fuel leaves more space for vapour in the tank. Agitation is well known to increase vapour pressure. To prove this for yourself put an ounce of gasoline in a plastic container, put the lid on, and shake it. Or shake a plastic gas can. They will swell up.

Hey Wasp18 – yes, you have it right, that’ll do it – maybe Kevin the OP will let us know exactly what he did, though.

- Brian.

[Catigale]

50-100 degrees F is a 10% change in pressure which is about 1.4 psi , certainly enough to pop the tank back.

The Reid vapour pressure for gas (a mixture of hydrocarbons, so a true vapour pressure doesn't actually apply) roughly doubles from 50 to 100 F,,,a much bigger pressure effect as noted.

[RobertB]

You guys crack me up.

I still think a shot from my air compressor would have been a whole lot quicker.

[kmclemore]

...which is why I said to put about a cup of gas in the can before heating it, which allowed for the gas to vaporize while also providing sufficient air volume for expansion. Too much gas would have reduced the surface area for vaporization.

[Catigale]

Imperial or metric cup?

[Crikey]

Looks like a big whoopee cushion!

[kmclemore]

Imperial or metric cup?

God Save the Queen, Steph.

[Kevgrn114]

ok, here is what I did.. I had about 2 gallons or so in the tank an did not have another container to offload some… I tried hot water for several hours but no change. by that time it was night and cooler so I set it on the garage floor and opened the air valve so the pressure would equalize. in the morning, I close the air valve and set it in the sun so the pressure could build up. It worked in a few hours. Using the air compressor may have worked but I would worry about it cracking from quick pressure. also it was easier to just close and open a valve than it was to try to fit the air hose sealed to it. You know that old rule of thumb where you let it do the work for you while you have a beer?!

[Catigale]

Well done.

They teach you that rule in Managers school...except its have someone else do the work while another intern gets you a beer......

[WASP18]

ok, here is what I did.. I had about 2 gallons or so in the tank an did not have another container to offload some… I tried hot water for several hours but no change. by that time it was night and cooler so I set it on the garage floor and opened the air valve so the pressure would equalize. in the morning, I close the air valve and set it in the sun so the pressure could build up. It worked in a few hours. Using the air compressor may have worked but I would worry about it cracking from quick pressure. also it was easier to just close and open a valve than it was to try to fit the air hose sealed to it. You know that old rule of thumb where you let it do the work for you while you have a beer?!

That explains the amount of gas inside your tank (2 gallons) when it was suggested to have only a cup which sounded logical. I wonder what the internal temperature was inside your tank at peak heat. What is the combustion temperature of gasoline vapor? Quite an experiment and one I hope I don't experience. However, if we all run into this problem, we know how to solve it.

[seahouse]

You guys crack me up.

I still think a shot from my air compressor would have been a whole lot quicker.

I dunno, RobertB…

I think a match would be even faster.

And it would crack you up too!

-B.