The Unofficial Mamod and Other Steam Forum

IndianaRog

Hi all,

A couple of weeks ago I shared a Meths fired Jensen 25 project I built...initially I used a Bowman sort of burner with meths tank and long slotted tube type burner...it created way too much flame.

Round 2...I changed the burner completely, more like a Mamod burner used on something like an SE4...with low tube connecting 4 upright burner tubes as pictured below:

This works beautifully, but the flames are still burning too hot and high (about 2 inches high given my tank is 1.5 inches high). I used rolled bits of asbestos to pack my burner tips and they burn quite evenly, just too high and it exhausts my meths supply in 5 minutes.

At the moment, the wicks are about 1/4 inch above the lip of the burner tips. Can someone advise if I cut them down will it reduce flame?? I would like to cut the flame in half if possible but don't want to cut too much off as I have a limited supply of the asbestos to workwith. Also, will tightness of packing the wick in reduce flame??? I have them snug but not really compressed into the burner tips.

Thoughts??
thanks,
Rog
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Stitch · Posted: Tue May 22, 2007 1:29 am Post subject:

Hi Rog
I can't comment with any certainty on whether or not cutting the wick will reduce the size of the flame. Perhaps reducing the size of the diameter of the upright tubes would slow down the consumption of the meths.

What I do want to say is that is a nice burner that you have made. Looks like excellent quality.

old_timer · Guest

I'm not 100% sure, so you may want to await other responses but I suspect a shorter exposed wick will lead to a smaller flame - I'm thinking a hurricane lamp scenario here.

Looking at your burner, would it be possible to try and compress say one wick down to about half the exposed height (i.e make it about 1/8") and see if that improves things. (Cover the other 3 up for this trial) If this works you could then follow suit with the remaining 3 - if not, pull it back up to match the existing 3.

edit: looking at your photo again, the wick closest to the reservoir does indeed look a little shorter and you end up with a shorter flame...but it is a little dirtier due to lack of oxygen supply I guess. This might be the problem with shortening the wicks

I'm not sure this will reduce fuel consumption though (but it might - it does in a hurricane lamp). Perhaps Stitch is right - you might need to restrict fuel flow to reduce consumption.

Chris · Posted: Tue May 22, 2007 8:01 am Post subject:

The only wick burner I have is for my loco. It has some form of glass fibre wick material. That is cut to only just above the tube. This still gives enough flame to keep the boiler up to pressure and helps with the meths consumption. This is lower than the instructions recommend, and lower than you will find people suggest on here.

The glass fibre style of wick also glazes over after a burn or two which I think also reduces meths consumption and flame height.

Works for me.

Wouldn't breathe in too deeply when you cut your asbestos wick though.
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Chris
http://www.chrisfisher-photography.co.uk

Wallace · Posted: Tue May 22, 2007 8:18 am Post subject:

Rog that's a real nice burner.

Recently I had a lot of trouble with a wick burner.

My main problem is the wicks were burning off. I had packed them too tight.

A long story short I ended up using ceramic wicks. But I didn't really look at flame height.

Judging by the article in the following link, you could look at the wick height. You say about 1/4"? This suggest 3mm, which is about 1/8"

Also, from reading, looks like the hole in the filler cap could have an effect.

So I'd try shorter wicks for starters

Here's the link

http://www.roundhouse-eng.com/spirit.htm
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Graham-Jilly · Posted: Tue May 22, 2007 10:48 am Post subject:

great information there Wallace thanks for that
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Mamodman123 · Posted: Tue May 22, 2007 10:49 am Post subject:

Shorten the wicks so they are only literally peaking out the top! I had this problem on my SE4 so I cut them right down and it sorted it out

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Steve_S · Posted: Tue May 22, 2007 11:57 am Post subject:

I think that the main factor in determining the flame size is the length of wick which sticks out of the tube, so yes, I think if you trim the wick length you'll get less of an inferno!

It's a beautiful burner!

IndianaRog · Posted: Tue May 22, 2007 12:11 pm Post subject:

Thanks all for comments...I fiddled with things a bit more last nite and found out something very interesting...I did NOT have the pin hole in the filler cap big enough. My burners were dying after 5 minutes, but upon cracking that cap I found they went right back up to same height I started with. SO...I drilled out the hole one drill size larger and extended burn time from former 5 minutes to almost 30 minutes...all with 1.5 inch to 2.0 inch tall flames.

So, Wallace your article was spot on about importance of proper hole in the filler cap...mine was clear, just too tiny and I think it must have been creating a vacuum.

I like the idea of possibly narrowing the burner tips. You might not have noticed, but my four upright burners were made from spent .44 magnum caliber ammo casings of nickel plated, brass construction. Such casings BTW make perfect burner tips with a spot of solder on the bottom to seal the primer hole. I have various other ammo calibers and will see if I can find a slice of one to slide INSIDE the .44 inch ID casing...effectively narrowing the burner diameter...if that is ineffecfive at lowering flame height, I will reduce wick height starting with one burner til I get it right, adjusting others to same height if it works.

For those who did not see my post a couple of weeks ago, the burner tank in this case is made from one end of a scrap Jensen boiler cut to be about 1.5 inches tall. The underside is the cap off the other end of a Jensen boiler. Pays to hang onto scrap boilers for such experiments!!! Very stout beastie, you could stand on it without damage.

I will update later on results of burner narrowing and wick height reduction...so far just very pleased to have sorted out key need for proper diameter vent hole in the filler plug (a former Wilesco pressure valve BTW).

cheers,
Rog
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Griffin · Posted: Tue May 22, 2007 12:25 pm Post subject:

Roger, I was going to ask if you had used spent ammo case's for the burner, but you have already answered that question.

I think you could be on the right track in reducing the .44 casing's diameter down, as they could be on the large side.

Maybe something on the lines of 9mm would be better, just a thought.
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IndianaRog · Posted: Tue May 22, 2007 12:33 pm Post subject:

Trial and error on slimming down the burner orifice ID is definitely in order. I used the .44 mag casings as they were nickel plated and looked best with the burner tank, but the do seem like manhole covers in size!!! Stay tuned.
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Mamodman123 · Posted: Tue May 22, 2007 12:43 pm Post subject:

Nice one Rog! A handy tip to know!

What happens if you have no cap at all? My loco burner doesn't have one

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IndianaRog · Posted: Tue May 22, 2007 1:21 pm Post subject:

MM...I would imagine burners would operate fine with NO filler cap at all, but I would be concerned with potential for spills of meths, and a whole lot bigger fire, especially when these locos seem to be able to do aerial stunts on sharp corners!!
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Chris · Posted: Tue May 22, 2007 2:57 pm Post subject:

I've derailed my loco with a meths burner with no resulting fire ball. I was a bit worried though, and wouldn't recommend it!

There is a baffle between the meths tank and wicks with the loco burners.

I have been tempted to make a small bung with a little hole in though to fit over or in the filler hole.
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IndianaRog · Posted: Tue May 22, 2007 3:04 pm Post subject:

Chris, if the loco meths burner fill hole is wide open, perhaps there is good reason for that (venting, no vacuum buildup in tank)...but I for one would feel more comfortable with a vented plug of some kind to stem the flow of meths if it should upend itself.

I have had a couple of meths fires and only a wet towel would put them out...I have now added a fire extinguisher to my workshop for the next one!!!
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