Make Your Own Meths Burner

> So the DIY burner is efficient enough but I think it was really not working

It's efficient, but it's not working... hmmmm...  In what way is not working?

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edit - but if I put a smiley right (or any text!)next to it I get BSOD

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wierd: BSOD if I don't put 'other text' beside it, but okay its own...

> I am stubborn, I know a  red bull inverted cone burner would be easier as you have given more support but I like the way the smaller burner will store

Stubborn is okay...  Think of building red bull burners as gaining construction experience, then your final burner will be much neater, and work better.

> That sort of tab joint was what I made at the bottom but the tab broke off.

Yes, that can happen if you fold it too firmly.  It's worst when it happens after you've got the burner assembled, and are pressing a bit harder to align everything and tighten it up...  Poink! and the inner wall disintegrates...  The same can happen with the interlocking slot joint, except that it puckers and tears in the centre of the overlap.

> When you make an inverted cone red bull inward facing jet burner do you turn over a rim to the central hole

Sometimes I do, sometimes I don't.  I'd recommend starting without, as it's quite hard and time-consuming to do.  I have a very fine pair of needle-nosed pliers.

> and if so at what point in the assembly do you do it?

Before the three parts are mated.  I've made enough that I've got the feel for how far to fold around a cutout hole.  I sometimes turn the fold over even further once the parts are mated, using the round shaft of a screwdriver.

> so, for instance I get yellow  at the tip of a flame of an uncovered chimney burner, but it goes blue when a pan is lowered on to it, what does it signify?

I'm not sure... it could mean that the meths isn't burning completely, because the flame is being quenched.  This might yield a whole range of interesting partial combustion products, ranging from C, to CO, to various bits of broken ethanol and methanol (and possibly higher products, too).  Or it might mean that it's buring beautifully to pure CO2 and H2O.  Frankly, I'm minded to think the former is true...

Ideally, I'd get a combustion gas analyser, and see what's left in the exhaust gases, but I don't have one.  I wondered about finding someone at the chemistry dept ofReading Uni, and seeing if they'd like to use is as an exercise for their gas chromatograph/mass spec labs.  But they've shut the dept, I think...

oh

was hoping the latter - does look good though  - blue flame just like on a 'real gas cooker'!

Suck it and see Mole.  Try two different heights for the bottom of the pot, high for some yellow flame and low for all blue, and do a comparison of time and fuel weight to boil the same amount of water.

Then tell us the results.

captain paranoia wrote (see)

I'm not sure about the concern over yellow flames.  They only bother me if they're associated with sooting.  All they indicate is that the flame has got hot enough that any unburnt carbon flares to incandescence.

If you lower the pot so that the yellow flame disappears, it's likely that you're quenching the flame as you suggest, so that you're getting unburnt carbon, but it's not glowing.
As for whether jets are forming or not, ask yourself why you want jets.  What purpose do you think they serve, and do they result in improved combustion?  If you have a burner that works efficiently, although apparently without jets, why do you need the jets?

I am concerned about yellow flame because I see it as a sign of incomplete combustion. The presence of unburnt carbon, incandescent or not, is a sign I thought  that there might be excess CO. As I am going to cook inside the tent porch sometimes this bothers me.

 I wanted jets because I see jets as a way to entrain and mix air with meths vapour quickly and at a low level. It seems that a chimney burner like Mole extols would mix air and meths before combustion started which is good, but it takes up more space and might force me to bigger flissure clones. Perhaps  jets in a chimney stove might mix better still. The thermal feedback would be a problematically small I think.

captain paranoia wrote (see)

> So the DIY burner is efficient enough but I think it was really not working

It's efficient, but it's not working... hmmmm...  In what way is not working?

500ml boiled in 9 minutes, and continuing until 10:30 is an efficiency of about 66 percent.  Which is very good.

I thought the efficiency was good enough but I am concerned about CO. To me it looked like it might be working as a simple open pot burner.

 I cannot test the burner with my beer can pot which the burner is designed for because I am waiting for a silicone band I ordered. I imagine a simple open pot will have amorphous long flames which will not concentrate the heat on the small base of my beer can pot when I test that. My hope was that properly working jets would concentrate the heat inwards and shorten the flame length.

captain paranoia wrote (see)

> so, for instance I get yellow  at the tip of a flame of an uncovered chimney burner, but it goes blue when a pan is lowered on to it, what does it signify?

I'm not sure... it could mean that the meths isn't burning completely, because the flame is being quenched.  This might yield a whole range of interesting partial combustion products, ranging from C, to CO, to various bits of broken ethanol and methanol (and possibly higher products, too).  Or it might mean that it's buring beautifully to pure CO2 and H2O.  Frankly, I'm minded to think the former is true...

Ideally, I'd get a combustion gas analyser, and see what's left in the exhaust gases, but I don't have one.  I wondered about finding someone at the chemistry dept ofReading Uni, and seeing if they'd like to use is as an exercise for their gas chromatograph/mass spec labs.  But they've shut the dept, I think...

Frum wrote (see)

Suck it and see Mole.  Try two different heights for the bottom of the pot, high for some yellow flame and low for all blue, and do a comparison of time and fuel weight to boil the same amount of water.

Then tell us the results.

I am afraid I agree with CP. Without a gas analyser our only chance is frum's efficiency test. however I think experimental error may well mask small changes in efficiency which could point to dangerous variations in nasty gases.

Smell is another thing although CO does not smell. You can always tell when the 12-10 burner has gone out because there is a distictive smell

captain paranoia wrote (see)

> I am stubborn, I know a  red bull inverted cone burner would be easier as you have given more support but I like the way the smaller burner will store

Stubborn is okay...  Think of building red bull burners as gaining construction experience, then your final burner will be much neater, and work better.

CP thanks for all the info in this message, the part I have deleted,  it was what I wanted to know.

I should build a red bull for experience but life experience has told me that I do quite well at doing new things for the first time, so I try and take short cuts.

I took apart my burner, which was easier than it should have been. I built a new top with more rim inner wall included. This makes a better fit with my aerosol base. The top now sits a few mm lower so I made a new inner wall. Without noticing I used a steel  french 1864? beer can. I thought everything was hard but I did succeed in making a lower inner wall with a 2 slit standard joint, and a paper clip and to keep it shut. I believe the old top was the problem. I turned over the rim with large long nose pliers and turned a bit too much over and in an irregular way. The inner wall was mating badly on some of the irregular turned over stuff.

I had to open up my base a little wider and deeper using the top which actually pressed on to another aerosol can base for insertion. I now have a little lip of base sticking up which I can turn over to lock the top down. I have not turned down a rim on the top. Everything looks a lot neater. The capacity of the burner is probably only 25ml now. I want to add an Al cover to the central meths reservoir at about the 10ml level so that a 15ml burn starts with an open central pool for priming but quickly the meths is hidden from the heat above. I am hoping to reduce heat feedback to the reservoir meths and heat the meths in the vapour chamber more. I was thinking as an extended test of adding an experimental 45 degree upward facing conical skirt to the outside of my base, to reflect and conduct more heat to the outer wall. I would be interested if the skirt reduced the burn time.

> I should build a red bull for experience but life experience has told me that I do quite well at doing new things for the first time, so I try and take short cuts.

Okay.  I only suggesting practice because you seemed to be having trouble making conic walls, and were worried about the limited number of aerosol cans you had.  I notice you report that your recent efforts weren't so successful...but not too surprising if you were trying to work with a steel can...

Kronenbourg 1664 cans are indeed steel.  They no longer register on my 'can radar' at all; instinctively disregarded...

I look forward to hearing how you get on with the heat reflector; it's an interesting idea.

Hi Cp,

surprisingly the problems I had, I put down to poor technique which happened to be on Al components , practice would have been good.

The kronenbourg 1664 part was a replacement and seems to be fine, although: it is not tested, it adds an unneccessary gram to the burner weight, and I will try to avoid doing it again because it was bloody hard, there just might be problems with differential expansion or rusting or something. 

I reconstructed my aerosol 44mm diameter burner with a trial cover that covers the last 10ml of meths in the central reservoir. It has 12 jet holes about 1mm, the size of my dividers.

I tested my DIY burner, against, my TD 12-10, and  also did a test of my DIY burner with a inverted 45 degree cone attached to its outer wall to see if it reflected heat to give more feedback and a faster burn. I was using a MSR kettle in a Caldera cone.

The following were all with tap water weighed at 500 gram at 18 degree C, using 12 gram of meths (15ml).

DIY first steam 9min 34 seconds, full boil in 9 minutes 53 sec went out at 10min 55 sec,

12-10 first steam, 6minutes 30 seconds, went out 6 minutes 48 seconds, not quite a boil.

DIY plus reflector, steam 7 minutes 49 seconds, boil 8 minutes 16 seconds, went out 10 min 10 seconds.

The reflector seems to have an effect I was surprised how much of an effect. The reflector is 44mm bottom diameter and 104 top diameter, it is made out of the wall of a standard can, the height of a 440 can is just big enough. It is held together with a 2cm paper clip in a double notch in the overlap of the top diameter. It weighs 3 grams. It just grips by friction onto the outer wall of the burner about 5mm up from the bottom. It is quite an asset to be able to print out a paper template to see if it fits on a piece of foil, even if I actually mark the shape out by scribing with dividers, thanks again CP. The reflector as described seemed right for the situation. The heat source to be reflected is the heat from the flames on the bottom of the kettle, the kettle is only slightly bigger diameter than the reflector.

If I made one for my beer can pot I might well make it smaller and steeper angled. If I used this one it would almost touch the clone all round.

The Diy burner did have jets but they were weak. There was still too much yellow flame for me and there was sooting of the pot to a greater extent than the 12-10.  The jets were a little stronger with the reflector and maybe the sooting was less but it was all marginal.

I think my next trial will be to buy some heat proof sealer, gasket cement? fire cement? plumbers jointing paste? any suggestions? to ensure a seal of the top to the base wall and the top to the inner wall, and the inner wall joint. I do not really believe any of the joints is gaping wide as I held each join up to a light before final assembly but something is not right. I know there can only be a pressure difference of say 10mm of alcohol whilst mains gas is probably 150mm of water but I hoped. If that makes no difference then I do not know how some people get well defined jets several cm long.

Maybe a penny stove would get higher but still controlled pressures

That's an interesting thought.  How about sticking a simple chimney over an existing jetted burner?  I've made simple chimneys by sitting a can base (with dimple and side holes) over a simple open cup before, but never over a jetted burner...

> It has 12 jet holes about 1mm,

1mm is quite big.  I'd suggest experimenting with smaller holes.  I'm using 0.6mm at the moment.

> If I used this one it would almost touch the clone all round.

I know that you're concerned about incomplete combustion and CO.  How does the reflector cone affect the air supply to the burner?  I take it that your burner is more than 35mm tall?

The boil and burn times are interesting.  There are probably two things going on: better use of heat by directing it to the pan, and thermal feedback to the burner (hence the reduced burn time).  Have you tried a simple sheet of foil under the burner?

> I think my next trial will be to buy some heat proof sealer, gasket cement?

The common one seems to be JB Weld.  I've never used it.  One of the car exhaust sealants, or gasket compounds, perhaps?

> If that makes no difference then I do not know how some people get well defined jets several cm long.

Outward-pointing burners give good jets, because they don't blend into one like and inward-pointing burner does.

Then again, with an open-pot burner, as you say, there's not much pressure anyway.  You often see bubbles coming out of the fuel ports at the bottom of the inner wall.

This is starting to veer much more into the 'meths stove Q&A' thread territory, whereas this thread was really started to discuss my burner article.

> Perhaps  jets in a chimney stove might mix better still. >That's an interesting thought.  How about sticking a simple chimney over an existing jetted burner?  I've made simple chimneys by sitting a can base (with dimple and side holes) over a simple open cup before, but never over a jetted burner...

My original thought was" like a bunsen burner", I thought the heat feedback would be too small and it would go out/not prime. On another thread you said that chimney stoves start burning at the air inlets. The double wall 12-10 I have stops you seeing that. Anyway that is like a bunsen that has blown back, lots of heat feedback

< I know that you're concerned about incomplete combustion and CO.  How does the reflector cone affect the air supply to the burner?  I take it that your burner is more than 35mm tall?>

Its only 32 mm high I made it as high as the burner not thinking about how it would not hold right at the bottom. The TD cone is much wider than 104 mm diameter so there is room for the air to move round the reflector but it is probably a little too big. If anything combustion seemed better. If I made a reflector for my narrow clone  it would be narrower and lower and maybe steeper

<I think my next trial will be to buy some heat proof sealer, gasket cement?

>The common one seems to be JB Weld.  I've never used it.  One of the car exhaust sealants, or gasket compounds, perhaps?<

I used some silicon sealer tonight it worked and did not char but did not give me jets.

>The boil and burn times are interesting.  There are probably two things going on: better use of heat by directing it to the pan, and thermal feedback to the burner (hence the reduced burn time).  Have you tried a simple sheet of foil under the burner?<

We always use foil under the cone when camping to protect the ground. I was not using it on these trials as I was doing it in the basement on a stainless worktop to reduce fire hazard. The stainless gave me extra flame reflection views. I imagine if the reflector became standard we might be able to loose the foil. I am pretty sure the reflector is protecting the ground better than foil. The hot spot is probably under the burner itself.

>This is starting to veer much more into the 'meths stove Q&A' thread territory, whereas this thread was really started to discuss my burner article. <

I can find the meths stove Q+A and use that from now on if you like?