Re-filling the gas

[ProDave]

Just had my first attempt filling a Calor 4.5kg from a Calor 15kg which stopped with about 3kg transferred however long I waited. I warmed the donor bottle with a towel and kettle and went away for an hour. When I came back I had transferred 5.5kg and the receiver bottle was completely full.

This is not a hands off leave it to itself, come back and check later exercise.

You should be in attendance and keeping a check all the time. Don't start it until you have enough time to finish it.

 

[jaminb]

Not sure why but I have ended up with Calor 3.9kg Propane on my boat. I had 3 on rotation but have just swapped one for an 11kg at £45 to power a 3 way camping fridge (not for the boat). Is the refilling process the same for propane as butane? I can buy an empty 13kg propane cylinder for £40 and then exchange for a full one which I would hope can refill both remaining empties and should last me a season.

Otherwise I am looking at expensive camping gaz, i already have cylinders and a dual regulator, or the expense of starting from scratch and converting to Flowgas or Gaslow (which looks very expensive!). What a right royal pain in the axxe.

 

[fredrussell]

… Is the refilling process the same for propane as butane?

Yes.

 

[andsarkit]

This is not a hands off leave it to itself, come back and check later exercise.

You should be in attendance and keeping a check all the time. Don't start it until you have enough time to finish it.

I quite agree. My first attempt took 12 hours with long periods of no flow.
I was just pointing out that it is not a simple matter of pouring gas from one bottle to another. If my memory is correct Joule-Thomson and PV=RT come into play and the temperature effects control the flow which is not linear.
Now that I have a better handle on the process I should be able to fill the next bottle in less than an hour.

 

[rotrax]

we use a 907 campinggaz cylinder every 2 to 3 weeks, so thats. 3 or 4 cylinders a year as we like to eat well onboard for the 10 to 12 weeks afloat

We probably use one or two 3.9 Kg calor propane in the van as its more cramped and often pub near we stop

For both boat and van, the size of cylinder is a major problem and we cannot readily go to 7kg calor so refill strategy is attractive

I can see that. Camping Gaz at the UK price of approx £45.00 for an official 907 refill is a serious pisstake.

Cheaper to buy the connector pipe and a large donor cylinder and fill your own.

4 X £45.00 = £180.00!

Calor are 'avin a larf!!!!!!!

 

[B27]

I can see that. Camping Gaz at the UK price of approx £45.00 for an official 907 refill is a serious pisstake.

Cheaper to buy the connector pipe and a large donor cylinder and fill your own.

4 X £45.00 = £180.00!

Calor are 'avin a larf!!!!!!!

I suspect a lot of users get through one or two camping gaz cylinders a year.
If you charge for the faff and labour of filling one, maybe re-furbing the cylinder, the assurance of having a cylinder which has been inspected in recent memory, it's a little different.

I've often found a camping gaz cylinder is a nasty rusty thing by the time it's empty.
In fact the full one I've been carting around, while using the dregs of an old one, is already looking in need of a paint job.

 

[rotrax]

I have a 907 in the workshop for the gas torch. It is the same bottle from when I closed our business. That was in 2004.

Bottle is dusty but not rusty. Not bad for 19 years.

The gas torch does not get much use...............................................

The Camping Gaz 907 holds 2.71 kilos of gas.

Exchange price around 45 quid.

Good Value? I dont think so.

 

[B27]

I have a 907 in the workshop for the gas torch. It is the same bottle from when I closed our business. That was in 2004.

Bottle is dusty but not rusty. Not bad for 19 years.

The gas torch does not get much use...............................................

The Camping Gaz 907 holds 2.71 kilos of gas.

Exchange price around 45 quid.

Good Value? I dont think so.

Maybe they used better paint 19 years ago?
Or maybe it's not rusty because it hasn't been on a boat.

The paint they use is even less effective than the white paint they use on small trailer wheels, and that's pretty bad.

After 19 years, is the rubber seal still OK?

 

[lustyd]

Bottle is dusty but not rusty

Rust isn't the main issue with pressure vessels. The metal will work harden with heating, cooling, filling, emptying. Then one day you'll be merrily working away and it'll fail catastrophically with a crack, probably on one of the flat sides.

I'm not saying that justifies the costs, but after 19 years it's probably time to return it so it can be tested regardless of appearance. Dive cylinders are now 5 years between tests, although much higher pressures involved. A quick Google suggests 10 years in the UK so you're approaching double the recommended which would usually be where I'd draw the line as I'd assume they add a safety margin

 

[rotrax]

There is NO comparison to the internal pressure of a charged Diving cylinder and a Butane or Propane cylinder. That is why diving cylinders are regularly inspected and discarded after their perscribed life.

My 19 year old 907 is still on great shape. After your post was read I went into my workshop and fired up the gas torch-all good. A bit of soapy water around the valve shows that is gas tight too.

It is not rusty because it has always been kept in a commercial workshop or my home workshop which is at least to the same standard. Once the dust was wiped off, it looks better than another I have 'in stock'.

Please let me know where I can find a flat side on a Gaz 907 cylinder or other pressure vessels.....................................................

 

[rotrax]

Maybe they used better paint 19 years ago?
Or maybe it's not rusty because it hasn't been on a boat.

The paint they use is even less effective than the white paint they use on small trailer wheels, and that's pretty bad.

After 19 years, is the rubber seal still OK?

See post # 30.

 

[lustyd]

That is why diving cylinders are regularly inspected and discarded after their perscribed life

As I said though, gas cylinders are regularly tested too just not by the consumer. The problem is identical and your cylinder will be much thinner metal and will have had 19 years worth of daily expansion and contraction.
The flat sides are the sides, it’s not a sphere!

 

[rotrax]

As I said though, gas cylinders are regularly tested too just not by the consumer. The problem is identical and your cylinder will be much thinner metal and will have had 19 years worth of daily expansion and contraction.
The flat sides are the sides, it’s not a sphere!

Your definition of flat is far different to mine.

The normal shape of a liquid gas cylinder is a tube with rounded ends. A valve is fitted to the top.

A straight edge will not lie flat against the sides, top or bottom of the cylinder. To ensure they stand up a ring of shaped metal is welded to the bottom.

Ergo, no flat areas.

I agree the material they are made from was ONCE flat

Gaz 907 cylinders and I go back a long way.

The picture shows my wife and I in Wroclaw, Poland in September 1970. A 907 cylinder can clearly be seen on the rear carrier of our BMW motorcycle. In my experience these gas cylinders are very strongly made and failures from old age of the cylinders is extremely rare. In over 50 years of 907 use I have never had a valve failure.

 

[Steve_N]

After 19 years, is the rubber seal still OK?

The rubber 'seal 'in top of a 907 is nothing more than a loosely-fitted dust guard - all works fine without it. The gas seal is the steel ball bearing below it in a steel seat. Once the regulator or adapter is screwed in and the ball bearing is depressed then the gas seal becomes the (replaceable) flat rubber washer on the regulator/adapter.

 

[lustyd]

The normal shape of a liquid gas cylinder is a tube with rounded ends

Not sure how you couldn’t work out I was talking about the straight tube part. Possibly just being difficult because you don’t like that I’m right.

 

[Sandy]

Are the 907 size bottles still available?

Yes. Go Outdoors are pretty competitive if you have their card.

 

[jaminb]

With a twenty quid connector pipe and a new 15 kilo Calor Propane cylinder I easily got 3 kilo's of gas into an empty Calor 3.9 cylinder.

My old racing mate Bob, a refrigeration specialist, told me by cooling the reciver and warming the donor, I could have got more liquid gas in.

That is what he does when decanting refrigerant gasses. Something he frequently does, and has done for years.

Now Calor are taking the piss, I am sorted. The 3 kilo self filled bottle lasted four weeks on our recent five week cruise. Assuming I can get four fills from the 15 kilo donor bottle, £12.50 a fill. If I can get five, a tenner a fill.

Watch this space for further reports - going to do the second fill of the empty cylinder later today.

rotax have you got a link to the twenty quid connector pipe - I can only find them for £40 on ebay. Still dont think I can buy the part for this but if I can save £20 that's 2 refills!

Thanks

 

[john_morris_uk]

Your definition of flat is far different to mine.

The normal shape of a liquid gas cylinder is a tube with rounded ends. A valve is fitted to the top.

A straight edge will not lie flat against the sides, top or bottom of the cylinder. To ensure they stand up a ring of shaped metal is welded to the bottom.

Ergo, no flat areas.

I agree the material they are made from was ONCE flat

Gaz 907 cylinders and I go back a long way.

The picture shows my wife and I in Wroclaw, Poland in September 1970. A 907 cylinder can clearly be seen on the rear carrier of our BMW motorcycle. In my experience these gas cylinders are very strongly made and failures from old age of the cylinders is extremely rare. In over 50 years of 907 use I have never had a valve failure.

Why did you hang a bunch of bananas over your wife’s shoulder?

 

[boomerangben]

Rust isn't the main issue with pressure vessels. The metal will work harden with heating, cooling, filling, emptying. Then one day you'll be merrily working away and it'll fail catastrophically with a crack, probably on one of the flat sides.

I'm not saying that justifies the costs, but after 19 years it's probably time to return it so it can be tested regardless of appearance. Dive cylinders are now 5 years between tests, although much higher pressures involved. A quick Google suggests 10 years in the UK so you're approaching double the recommended which would usually be where I'd draw the line as I'd assume they add a safety margin

Does this actually happen? Are the stresses within the steel of a bottle sufficient for work hardening to be significant? I can’t find anything on google so am interested to hear more

 

[rotrax]

Why did you hang a bunch of bananas over your wife’s shoulder?

I think you will find it is my right hand. I had fat fingers in those days!