I’ve been told that some users of Tilley lamps with steel tanks (PL53, FL6 etc) add ‘a teaspoonfull of meths’ to each tankfull of paraffin. The purpose is apparently to trap atmospheric moisture introduced by the air pump and prevent it corroding the base of the steel tank. I wondered if this is a widespread practice and whether it has any scientific basis. A quick experiment this afternoon was inconclusive as I probably added far too much water to a sample of paraffin! All suggestions welcome. Phil
Methylated spirits is hygroscopic i.e. it absorbs moisture from its surroundings so yes, there is scientific basis as to adding a little to the paraffin at every refill.
Thanks, Henry, that makes sense. A few sums reveal that pumping 30 strokes of a typical FL60 pump of air at 20 deg C and 50% RH will introduce 0.034 grams of water into the tank. Not a lot, but over a period of time, the amount of water will build up. If the lamp were fired up once a day, for example, with the fuel being simply replenished as needed, then in a month there’d be around 1 cubic centimetre of water in the tank. I believe the British Army issued instructions that all steel-tanked pressure lamps were to be emptied, drained, washed out and refilled with fresh paraffin on a monthly basis. This is clearly sound advice for lamps in frequent use. It would not require much meths each time the tank is filled to deal with that, so a teaspoon (5ml) seems a sensible amount. I will certainly be adopting this procedure for my three steel-tanked lamps from now on. Phil
Never heard of this before but i have swilled tanks out with meths to mop water up Good idea makes sense to me Cheers pete
It may be meaningful to use isopropylic alcohol, which also mixes better with fuel residues than normal ethyl/methyl alcohol.
