Red plastic ULP containers swelling

[Jon and Kay]

Just to help put my mind completely at rest....

I recently started using a 20 litre ulp container. I put it in the bin with the genny. When I went to change the oil in the genny, the container was bloated like one of those porcupine fish. I released the gas, by squeezing the sides in and put the lid back on, and moved it to a cooler spot. It still swells. Is there any history of these containers ever exploding? Should I use a metal container instead?

At the moment I believe it is just a function of fuel evaporating when hot and shrinking when it gets cold again. And , surely the container os fit for purpose anyway. But I would like some confirmation from those who have always carried fuel.

[BruceS]

Yes I've noticed that too Jon, although not too bad as I try to keep them in a coolish spot.
I'd worry about doing what you suggest as on a cold frosty morning they'd suck the sides in a lot.
Probably more likely to crack & leak with a vacuum than pressure.
Farm storage tanks have a breather 10ft in the air but we can't do THAT!!
Less likely to expand if full up too I think?

[T1 Terry]

It's one of the features of the plastic fuel containers, it may only hold 20 ltrs when you bought it, but by the end of summer it will hold 25ltr to 30 ltrs The Rheem black ones do it as well, but I've never seem one bust, but heaps of metal jerry cans that have split their seams and spray fuel all over the place. Much prefer the plastic containers, but ones designed and so labelled for the job, used oil bottles do bust, plastic milk bottles melt, Coke bottles delaminate from the inside out and glass bottle blow the metal cap off, so the made for the job plastic fuel containers are the safest of the lot.

Just another bonus with the plastic 20 ltr jerry cans, when you put them in the jerry can holder they self secure, I had to siphon the fuel into another container as there was no way I could get it out of the holder

[Jon and Kay]

Thanks Guys. I thought it must have been ok. I wonder if it would be better in one of those wire framed containers , or would it restrict a necessary expansion?

[T1 Terry]

It will find an unrestrained area to expand and the expansion will be concentrated in that area rather than over the whole container. Having said that, the surface area on the big sides would be subjected to more expansion pressure due to the greater surface area, but I guess that must be factored into the original design..... but that would have involved engineers and look up tables..... a bit of a conundrum there Jon

[Greynomad]

Our two 5 litre jerrycans likewise expand in hot weather & suck the sides in during winter.
No signs of stress fractures after 3 years. Still hiss when I take the lids off, and return to normal shape.
Don't worry about it... but also, make sure you only put in the prescribed 20 litres.
Don't be tempted to squeeze in the extra 3~4 litres the container will apparently take: that's expansion space for the vapours!
Our nominal 5 litre jerries will actually take 6.8 litres. Only ever used that capacity when I was planning to empty it into the ride-on mower immediately I returned home.
Never stored these jerries chockers. Asking for trouble!
When travelling, they carry exactly 5 litres each. In hot climates, they resemble puffer fish. In cold climates, they suffer anorexia!

[aussiegirl]

We also bought a red plastic jerry can after running out of fuel and it was the only sort the servo had. I was really concerned when it also swelled out like a balloon even though it was definately made for fuel. It has sat under the carport ever since as we were a bit frightened to use it again. Just thought it was a useless piece of crap that we got ripped off on. Seems they are meant to be like that. Might have to dust off the cobwebs and dirt and start using it again