As i was explaining the lighting technique a lady approached and listened intently. She was impressed with it and ordered one for christmas for her brother. Wow.
I have made quite a few stoves of differing types, some work and some don’t work so well, especially when you get on the hill.
It’s completely different making a stove and testing it in the comfort of the garage/kitchen/yard or whatever, to what actually happens when you are hiking and you depend on it in the hills.
I am not going to bore readers with the manufacturing technique or the testing summary, there is lots of that already on the internet.
However i will pass on some pointers for anybody who is interested and wants to have a go at making one for the first time themselves.
1. Any aluminium seamless bottle/container can be used. The above are bud bottles but aluminium deodorant spray cans work just as well.
2. There is no need to spend time removing the advertising from around the bottle. For one, they look fine in red anyway, but sanding down the bottle just reduces the wall thickness and you don’t want to do that.
3. I’ve tried both Methylated spirit and Surgical spirit and they both performed exactly the same. You can see in the photo’s, the purple residue is Meths and the blue residue is Surgical spirit. The only difference is the price. Surgical spirit is dearer than Meths, but you could use SS to clean a wound if you are in the habit of having accidents with barbed wire etc.
4. The jet sizes i used were 1mm, 0.5mm and i guess the sewing needle is 0.4mm. There is very little difference in efficiency with similar sized stoves. The spirit burns at a similar rate whatever.
5. It is most important that the top edge, where the pan sits is as flat as you can get it. If it isn’t flat then the vapour will ignite at the leak points and cause a flame peak.
6. Where the jet size does make a difference is in relationship to your pan width. If it’s a wide pan, over 130mm across, use 1mm jet hole, if its a Ti mug/ typical cup around 80mm, then use 0.4mm.
My pot measures 120mm across so i found 0.5mm suited best.
If you use a jet size that is too big for the pot then the heat comes up the side of the pot and escapes to atmosphere and also will heat up the pot handles whereas a smaller jet size will just take a little longer to boil.
7. Don’t use too wide a pot as it will become unstable on the stove, especially in bad weather.
8. Now that the days are getting colder. Try and keep your fuel and stove warm, make a cosy for them from either closed cell foam or something similar. Keep them in the tent at night and not in the porch where they could get frosted. Warm gear means that the fuel with vaporise and bloom faster.
9. Also keep your water bottle in the tent. Those extra few degrees higher temperature makes a big difference to the boil times.
10. Use a priming pan and put a few drops of fuel onto the pan this will decrease the bloom time. (Bloom time has nothing to do with plants! it is the time it takes for the fuel vapour to be ignited at the jets.)
11. Don’t put the pan onto the stove until the jets are fully lit otherwise the stove will go out.
12. Use a cut down coke can to put your stove out. Don’t waste fuel by just letting it burn out. When the stove is cool tip the stove upside down and drain the fuel into the coke can. Then by squeezing the side of the can slightly you can pour the excess back into your fuel bottle.
13. Keep the stove as much out of the wind as possible and use a wind shield.
14. I have found that using a long nozzled gas lighter is best. Far better than anything else.
Well that’s it for now. Hope some of the points i have raised will save you time and equipment but have fun making them anyway. And don’t forget the cost in monetary terms is nothing to have a good backpacking stove.
In extremis, which of the spirits is the best for drinking? Backpackers should have dual use for every piece of kit carried...
ReplyDeleteI think i would go for the surgical spirit if i was that desperate. Definitely not the meths.
ReplyDeleteSurgical spirit has a strong smell of Germaline. I don't recommend either.
It would be good if somebody came up with the ideal product to suit both purposes at the right price of course.
I'm sure you will be quite sick of the smell of surgical spirit though by now.
Great information there! One day I'll actually get round to trying to make one of these :-)
ReplyDeleteHi Simon,
ReplyDeleteThanks for the comment.
They really are a great little stove. Compact, light, strong and efficient and most of all cheap.
Yes, have a go at making one and if you need any more info, please ask.
Good work there, interesting regarding jet sizes. I think simplicity is the key as I experimented with different designs but it's swings and round-a-bouts.
ReplyDeleteYour absolutely right about real world results, the web is full of stories about wonder stoves but quite often they've been tested indoors and 'Boiling' is when the stove builder can see bubbles, that could be anything from 75°c upwards.
Richard,
ReplyDeleteThanks, there was a lot of work done over the last few weeks when you start to consider different stove sizes, fuel volumes, jet sizes, pan sizes, wind shields, fuel types. I think i have enough data now to know when to stop testing.
Nice write up. It sure would have helped me a while back when I first decided to get into alky stoves. The thing that got me was indeed matching my stove with my pot size. I had made a couple of Pepsi can stoves and they all worked great. But then I bought a 700 ml Ti cup / pot and decided to buy a smaller alky stove to match it for solo trips. The first stove was too big, even though it was a solo, so I eventually got a Gram Weenie Pro. Works perfect.
ReplyDeleteAlso, I always use a fire steel to light my stove. Works every time and I don't have to worry about a lighter not working. Good note here though, don't push out with the striker, but instead pull back on the Ferrocerium rod so you don't knock the stove over while lighting.
Thanks Stick.
ReplyDeleteI have a Gram Weenie pro too and when i first tested it i din’t think much of it. But i took it on my last solo trip and found it worked well.
My thoughts on fire steel’s are this.
Have you ever seen that advert where the Ninja is displaying his sword swirling skills just before a fight, then the cowboy just draws his gun and shoots him. Well in my opinion the gas lighter will always win too.
I am well aware that if it can fail then 1 day it will. But 2 years on with the same Bic lighter and it’s fine. (But i keep a few windproof matches tucked away just in case)
Thanks for the lighting tip all the same. I will remember it.