# hi



## superten67 (Nov 3, 2012)

hello guys im having a problem with a little furnace ive built,theres a fixed tube going through the wall of the furnace thats threaded at one end and it will thread on to a camping gas bottle,or calor gas whatever you want to call it.
but when the torch is lit and you try to put the lid on the gas is starved of air and goes out.
there is a vent hole towards the top of it but im wondering is the vent hole big enough?
i know it needs to be vented for the air to get in and the heat to circulate and breath but do i need to drill the hole out from the 10 mm diameter it is?
any help will be great.


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## qst42know (Nov 3, 2012)

How well does it burn with no lid?


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## superten67 (Nov 3, 2012)

it burns fine with no lid i think its cause of the bottle having not enough pressure may have to go to a large bottle and just attach the larger pipe from the new bottle to the smaller pipe with jubilee clips.
ive also tried putting the nozzle straight in from my rothenberger nozzle and map gas but it still goes out.....so it has to be the pressure right?
but im also conflicted when i think about the fire trianlgle if i block the lid off completely it goes out how am i ever going to build up enough heat to get to the high temperatures that are needed to mel t the gold ive refined?
and i know i can met it in a dish with map but i do have lots of other stuff to be getting on with which is why i made the furnace so it could be left unattended.


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## GotTheBug (Nov 3, 2012)

Pics would help. Sounds like you have no way of mixing in air with the gas before it hits the combustion chamber. Take a look at any small gas (propane in particular) appliance and you should see an opening somewhere for air to enter the stream and combine with the gas just before it reaches the combustion point. Also, I do hope you're not planning to use those small 1 pound "disposable" cans of propane, like for camping, for a furnace. You will spend a LOT of money doing that.

Paul.


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## Geo (Nov 3, 2012)

is the fuel supply into the bottom vented or sealed. the difference it makes determines how it will operate. many furnaces have a larger hole at the bottom with an adjustable vent to regulate air/fuel mixture. if its just sealed where only fuel can enter, air or oxygen needs to be mixed with the fuel before it enters the furnace. without this air supply it may never work right.


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## superten67 (Nov 3, 2012)

yep i see the problem yes it is sealed,so if i put a hole through the inlet pipe near where it enters the furnace the furnace then in theory that should cure the problem as when the gas is going down the pipe it will drag air in as it goes?


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## Geo (Nov 3, 2012)

superten67 said:


> yep i see the problem yes it is sealed,so if i put a hole through the inlet pipe near where it enters the furnace the furnace then in theory that should cure the problem as when the gas is going down the pipe it will drag air in as it goes?



if you just put a hole in the fuel line, it will just let fuel out of both holes at equal pressure. you need to put a short piece of pipe in the bottom of the furnace thats at least a quarter inch larger than your fuel line. then run the fuel line into the larger pipe loose. make sure the fuel line is well into the larger pipe but stops short of reaching the end of the larger pipe by at least an inch.that way, when the fuel is injected into the furnace, it will pull air in with it.


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## superten67 (Nov 3, 2012)

yep i get it now mate,i didnt see it to start but now i do and thanks for taking the time to explain ive got the exact bit of pipe for the job.


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## bswartzwelder (Nov 4, 2012)

I would think that if the hole is near the top, that would be where the hot gasses would escape. There should be a hole down low so that cold air can enter from the bottom, mix with the gas, burn, and exhaust gasses could escape through the top hole. I may be way off base here, but by forcing a little air into the bottom of a pile of charcoal, I have created a small forge which can heat 1/4 inch thick steel cherry red in a matter of a few minutes. Let us know if this helps.


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## samuel-a (Nov 4, 2012)

[youtube]http://www.youtube.com/watch?v=VxzdqcPzXj8&feature=related[/youtube]


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## butcher (Nov 4, 2012)

Thanks Sam,
I have built several of the Ron Reil and other style propane burners, including some propane burners which are very similar to this one, they work good, what I really liked in the video is the blacksmith forge, his design has given me some more ideas for a new forge.


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## superten67 (Nov 4, 2012)

cheers guys all done bigger pipe is installed put the map torch in preliminarily and then put the lid on and it works fine.
all i need now is a bigger bottle and rig up a nozzle that leaves me a quarter inch gap.
then because its such a small furnace the gas should last forever and the furnace should be really efficient.


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