Storing and transporting fuel

Polyethylene or steel? Choose wisely, then use accordingly.

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In these days of fluctuating petrol and diesel prices, many people hedge against high prices by filling up when the price is low, with some laying in an extra supply in suitable containers. There are also those people on long overland journeys beyond our borders, where filling stations are few and far in between. Both have a common need: a convenient and safe container to store fuel.

What’s in a can?

Fuel containers come in two main types and are made of two different materials – polyethylene and steel. The latter is the traditional jerrycan, a venerable carry-over from the Second World War. Dating back three-quarters of a century and never improved upon, it is still the standard today.

Each type has its own characteristics, advantages and disadvantages, and share a few common challenges and problems. Polyethylene fuel containers cost about the same as steel jerrycans. However, the larger polyethylene container holds 25l while the larger jerrycan can hold 20l.

Neither is supposed to leak, as the lids close down on highly effective rubber seals. Vent systems let in air to replace displaced fuel when pouring in order to prevent splashing. In the polyethylene container, a screw-on funnel is normally included in the price, while in a steel fuel can, a clip-on pouring spout is an additional accessory. Care should be taken while pouring to ensure that the spout of a plastic can does not slip; because of its telescopic flexibility, fuel will mess all over the place.

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A red Addis polyethylene fuel can for petrol use (R345). The alternative, an identical-looking yellow can (R285), is made of a different formulation of polyethylene and is used for diesel storage.

A fuel container should ideally be stored upright. A plastic container leaking at both the opening and the vent, even when standing upright, is potentially explosive. Slight shifting between adjoining cans and between the cans and the brackets, especially where sand and dust are present, will abrade the wall of the can. In extreme cases this can lead to leakage. Rust will appear when the paint on a metal jerrycan wears off. The better, more expensive Nato-quality jerrycans are coated with a tougher and better quality paint that lasts, but rather avoid abrasion in the first place by lining the bracket with rubber insertions.

Attached to a vehicle
Although polyethylene is tough, light, flexible and abrasion-resistant, it is more prone to penetration and damage than steel. When used for stationary storage, this is not a problem, but carried in a vehicle on a rough corrugated road on a hot day it is a different matter altogether. A variety of brackets and containers designed for carrying jerrycans securely on different vehicles is available.

Carrying fuel on a roof rack, even in purpose-made brackets, has problems and advantages. It is difficult to fill cans on the ground, get them onto the roof rack and tie them down. This entails at least two strong people and a firm place on the roof rack to stand. A ladder is also preferable, for taking the cans down again for refuelling.

The fuel can be siphoned from the elevated tank directly into the vehicle’s fuel tank by means of a jiggler siphon tube with an online fuel filter. The alternative is a custom-made second fuel tank fitted to the underside of the vehicle, or a custom-made larger single tank. The obvious advantages include easier filling, better space utilisation, more packing space and no cans to manhandle, stow and pour from.

Jerrycans on a roof rack raise the centre of gravity, increase wind resistance and are difficult to handle and stow, but enable fuel to be shared and allow fuel to be accessed in an emergency. Polyethylene cans unfortunately do not fit into the metal jerrycan brackets – a major disadvantage. Be sure to buy the correct type for the fuel type (diesel or petrol), as well as a spare can in case of a leaking seal. Take along spare seals, but buy the genuine article – a pirate part may not work properly.

Fuel can tips
Release the pressure on the seal during storage. Doing otherwise compresses and eventually destroys the seal. Ensure that the safety pin on the steel cap stays in position. Use a cable tie if necessary.
When transporting jerrycans on a bakkie load bed, secure them appropriately. If not, the cap may come off and the fuel will spill.

A Nato-type jerrycan, in contrast to the cheaper, lighter jerrycans sold by some chain stores, can endure decades of heavy use. I bought two such jerrycans at a camping shop for a 1994 expedition to Zimbabwe, Zambia, Malawi and Botswana. Since then, I have had to replace only one seal. The red anti-rust inner lining is still in pristine condition. The last drop of petrol from a year-old store is crystal clear.

The plastic containers offer more value in terms of fuel storage per container cost and weight, and are quieter when travelling. However, ensure they are completely leakproof, even when partially filled and exposed to the hot sun all day.