These comments are intended for Roger Caffin and are meant to be constructive rather than critical.
First I must say that although first taking a quick look at these series of articles a few weeks ago I am only now starting to read them as I spend as little time as possible anywhere near a computer! – and I just happened to look at Article No 6 first!
I use Kerosene stoves and WG stoves almost every day, and as such I would like to make some comments on priming.
Roger writes “However, with the most care in the world, priming a liquid fuel stove usually results in a fireball of some size”.
The priming of a liquid fuel stove should never result in a fireball of any size. I never get a fireball with any of the numerous liquid fuel stoves that I use.
With Kerosene stoves priming with methylated spirits only is all one needs. There is no need to “allow some kerosene to mix with it “(methylated spirits).
Some priming cups on some stoves are of poor design and do not hold sufficient methylated spirits to vaporise the paraffin. When this is the case and if the stove user opens the control valve too soon and then lights the “vapour” a large flame can result due to the incomplete vaporisation.
If one double primes – that is burn the meths in the priming cup and as soon as all the meths has been burt immediately refill the priming cup with meths and re-light. When the second prime is almost complete open the valve and the stove should light. If not immediately light the stove with a lighter. This is the method I use almost every day and I get immediate burner ignition and no soot.
I use the same method when using WG (although in the UK I use Aspen 4T [http://www.aaoil.co.uk/environment-Aspen-4T-alkylate-petrol] as it is less than a quarter of the price of Coleman Fuel.)
Some comments on the Optimus 8R. I am very familiar with this stove as I have several Optimus 8R’s of various vintages and a Russian military 8R copy.
Roger’s method of priming the 8R “Typically, you prime this stove by removing the fuel cap and blowing, hard, into the tank until fuel dribbles out at the burner. The big brother to this stove actually had a pressure pump, which saved you the taste of fuel.” Must be unique to Roger and is not to be recommended.
The Optimus 8R and its copies are very easy to prime: Fill the priming cup with methylated spirits, light and when the flame is almost extinguished open the valve. The stove should light immediately. In cold weather double priming as described earlier will ensure the stove will light. In very cold weather one can use the optional midi/mini pump.
In 1976 Optimus introduced this accessory for self pressurising stoves (Optimus 8R, 99, 80 and 123). The pump consists of a special, elongated pressure relief fuel cap and a small detachable, external pump to fit over it. Pressure is built up in the fuel tank by forcing air through the pressure relief cap. This pump is still available: In the U.K. from Base Camp: http://www.base-camp.co.uk/ and in the U.S.A. from A&H Enterprises in California: http://www.packstoves.com/cart/
There were at least three clones of the 8R. The Taiwanese copies are an Appolo and a Trail-Pak stove. The South Korean firm of Shinabro also copied it and sold it as a 170GR but rebadged it as a Precise Phoenix Backpacker which is an American brand name. The Trail -Pak stove is distributed by a Canadian company so it may be a rebadged Appolo.
With regard to Roger’s adventures in his tent with the 8R , and the unnamed BPL staff member with his SVEA 123 I would merely comment that when using small backpacking stoves one should use small pots/fry pans – sometimes it is not a faulty stove – just a lack of common sense on behalf of the user!
Roger says: “I have to add that kerosene stinks a lot more than WG!” I admit a bias here, being a kerophile rather than a kerophobe – but I personally don’t think good quality kerosene stinks at all – in fact I like the aroma of kero! Then, as someone who thinks that life is too short to drink bad whisky, my nightly dram of 25 year old Caol Ila’s “nose” would probably stink to those who don’t like west coast (West coast of Scotland) malts!
Recently in my part of Scotland we have enjoyed a lot of snow and temperatures down to -20C. I used my 1950’s Sievert Svea 123 running Aspen 4T at -13C in snow and by using good priming technique and having a small cut-off from an old kip mat the stove, insulated from the cold ground lit successfully every time (no fireball and instant ignition). At the lower temperature near -20C I used a 1930’s Optimus kerosene stove with equal success, no flames, no soot, just instant ignition after proper priming.
Sadly, every year in the field, I observe people using liquid fuel stoves incorrectly – none seem to realise that the flames enveloping their modern multi-fuel stoves whist attempting to prime is anything other than normal. It is sad because if they knew how to prime correctly they would have clean stoves, clean pans and enjoy their cooking and brews just a little bit more.
When time permits I look forward to carefully reading all the articles in the series in which Roger obviously put a terrific amount of hard work and enthusiasm.
Just to reiterate, my comments are meant to be constructive – I would like to see people use liquid fuel stoves safely and successfully.