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WayneF

Burner questions

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Hi all

i am looking for information / advice on my burner.

the flare is 1/2” to1” and still has the threads in it, is it best to remove the threads.

is it best for safety to use a armoured hose from the propane tank to my burner.

i remember reading in one thread that should no use thread sealant, is that only on the black pipe or at all?

 

thanks for your help

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No, I experimented around some years back and discovered burners perform a little better with internal threads in tack than removed and smoothed on the lathe.

Whether or not to use armored propane hose depends a lot of burner orientation. If they're top mounted then heat from the forge will rise up through them and can seriously over heat rubber. 

You need to use propane rated thread sealant and it's been found paste type causes far fewer problems. Tape can end up on the inside where bits can eventually come loose and cause problems down the line. Disrupt or even block the gas jet, flow rate through needle or shut off valve, etc. It's not a problem with the paste. 

Teflon tape and paste not rated for propane use can degrade and cause a fire hazard, not only from potential leaks but it can evidently turn into a type of thermite, which is B A D.

Frosty The Lucky.

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I meant to add some pictures of my burner setup, any recommendations are welcome. I am using a quick release for the hose to burner connection. 

I think I might need to redo my joints once I check on the tape I used.

Thanks for the advice frosty I plan on mounting the burner on the side of a pile of insulating bricks forge

 

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Were the cast parts originally from a burner? Because everything I think I know about gas burners  brings me to the conclusion that this is going to be a weak one...

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That looks like a 1/2 inch Amal injector. There have been a couple of threads on them here on iforgeiron. Apparently with the right orifice size they can be tuned to be pretty hot and when used in a forge do not necessarily need a flare. (if I remember correctly) 

These are just 2 In no specific order I hope they are useful to you:

https://www.iforgeiron.com/topic/59893-helium-tank-forge-with-amal-burner/

https://www.iforgeiron.com/topic/60905-amal-burner/

 

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Hi

yes it is a 1/2 inch burner as stock I have linked to it below. What makes you think it will be weak? Do you think a different injector nozzle will be needed.

i have to wait until the new year to buy the hoses etc before I can fire it up

 

http://amalcarb.co.uk/amal-gas-injectors/propane-injectors/1-2-injector-propane-gas-long-venturi.html

i have followed Tim Gunn instructions in this post I think I need to get a different nozzle

 

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3 hours ago, WayneF said:

What makes you think it will be weak?

The mixing tube looks to be too Long, and the flame retention nozzle is far from optimal.

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Hi mike 

 

sorry if if this is a stupid question but what do you mean by flame retention nozzle, is this the brass nozzle in the burner that passes the fuel into the choke or the flare at the end of the black nipple. Would you recommend another size nozzle if this is the part you are referring to. The black pipe is 9”

 

irondragon

I will change this out for a fixed connection then as I want to be as safe as possible, thanks for the warning.

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Not stupid questions Wayne. The mixing tube should be 8x the ID of the mixing tube and 9" is 18 x ID. Try a 4"-5" max mixing tube.

The flame retention nozzle is on the end of the burner tube the flame comes out. I don't like bell reducers for the flare but a lot of guys make them work. That one looks to be a 1/2" x 1" bell reducer and that's a bit much. Are 1/2"x 3/4" bell reducers available?

Frosty The Lucky.

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To be fair:

My primary concern was the configuration of the cast part of the burner, which appears to have too small a diameter in  its air intake. But Amal burners have a good reputation, so judgement should be suspended on that account; especially since this is a smaller burner at a bargain price. It would actually please me to be wrong about this burner, under the circumstances; that being a small burner for $40 :D

Why the negative comments about its mixing tube length and choice of reducer then?!? Because they are very likely to degrade the burner's performance--and thus to cover my six;. but the truth is, that they are also as easy a pie to fix.

Why come clean now? A good commercial burner at $40 is just too darn important to push off the table :blink:

 

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Hi all

I have now been able to connect up my burner and I have also changed the length of the burner tube to 4" and the reducer is now 1/2 to 3/4.

It produces a blue green flame, can you give some advice on what I am looking for in the flame

Cheers Wayne

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The flame looks rich. 

Greenish flame from burner= rich, reducing flame. (good for welding and less scale on work. Not good for breathing as it produces lots of carbon monoxide)

Pale blue flame from burner= neutral. (good or general forge work and is the hottest) I think.

Purplish flame from burner= lean, oxidizing flame. (Not used much, at least by me. Causes scale to form on the work rather quickly from excess oxygen)

 

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Also, make sure the seam inside the mix tube is smoothed down. A round rasp close to the pipe ID works for this. The seam can impinge proper mixing.

Or try increasing tube length a little.

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On 12/31/2019 at 11:13 AM, 671jungle said:

Also,

I forgot to say "change one thing at a time"

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Yeah change 1 thing at a time is something I have used and taught throughout my engineering career

 

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2 minutes ago, WayneF said:

I have used and taught throughout my engineering career

Perfect.

How's it coming? Im doing some recon on the amal burners right now. Lots of options for decent prices.

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I’ve not made the changes yet still need to get the fire bricks to make the forge itself, I want to get it all built before making changes as I have read here on the forum that the burners behave differently in the forge and out.

I currently have a 9” mixing tub and a 1/2” to 1” reducer to test with and of course the pressure adjustment.

 

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That is true, so far as it goes, which likely won't be far enough. The first thing you might look into is a smaller orifice for the gas stream to exit through; first, because a smaller orifice allows a stronger gas stream to exit through it for the same amount of fuel, inducing more air to mix that fuel with. Second, because your burner is made with gas jets sized for two different fuels: propane, and methane. I'm not sure if their are different jets for butane, or whether methane jets will serve for that too. But, propane is a harder fuel to mix air with sufficiently, then either of the other two.

Or, I may be completely off the mark. However, I want you to succeed...and you asked for a clue :D

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I did a bit of playing with jet sizes and found the Butane jetting to work very well on Propane forges.

I think the factory jetting is intended for “normal” heating applications which use both primary and secondary air.

For Propane forges, there is usually no secondary air so the Propane jetting runs pretty rich and not quite hot enough for welding. The Butane jetting is smaller, so runs less rich and a bit hotter when burning Propane: certainly hot enough for welding bladesmithing steels, though I don’t know whether it will manage WI welding temperature.

It’s still rich enough to limit scaling in the forge, so there’s some scope for reducing the jet size further to get even higher temperatures if needed. The Amal jets are available in closely-spaced increments and the sizing is pretty intuitive.

 

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It would be good if someone started an Amal burner thread, to collect information like this on them as (so far) they seem to be a bargain for people who want to buy their burners.

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Interested to see what others say. Other than speed, It's hard to tell what the flame is saying in the daylight. The mix tube looks long for a 1/2". Once in use, the nozzle should recess into the forge a little to reduce degrading. Bell reducers come in 316 stainless which will last longer than black pipe. It looks to be getting pretty hot. If the forge had some baffle doors it would get hotter.

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They are daylight videos  from a flame in an incandescent forge; Nevertheless, a much improved flame is shown than those outside the forge. The second point to be seen is that the forge has reached high-orange heat without the exhaust opening being partially closed.

Conclusion: good enough is good enough. "If it ain't broke it don't need fixing" :D

It could be that these burners are effected far more than other designs from burning in equipment. However, how clean is the exhaust ? A daylight photo isn't the best test for judging the exhaust flame...

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HI Mikey

To show the best detail what would you recommend when talking the video.

I plan on taking the video at night. for the exhaust there is no smoke of any sort that I could see.

 

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