Second attempt

[Old Boiler]

This is the second attempt at making a forge.
It's a 9 kg LPG bottle, fired with LPG via a 40 mm blower.
It simply does not get enough heat.
It is lined with clay from a bush termite nest, with a refractory inner lining.
Can't even get a glow.

Any suggestions?

[CurlyGeorge]

Got any pics of it. I think that you tried to post one, but it didn't take.

[pkrankow]

We need more to go on. How long have you fired it for? All that clay is pretty heavy and has a lot of thermal mass. What are the inside dimensions?

Fixing the picture would help too.

Phil

[Nakedanvil - Grant Sarver]

Interesting, the clay from a termite nest was the "high temperature refractory" used for the inside layer of the direct process furnaces used in Africa for a couple thousand years.

[pkrankow]

Interesting, the clay from a termite nest was the "high temperature refractory" used for the inside layer of the direct process furnaces used in Africa for a couple thousand years.

That is interesting.
Phil

[Old Boiler]

Unable to insert image for some reason.

The old bush blacksmiths used termite nests for forges apparently.
I could be on the wrong track from my result though.

I'll keep chipping away at it.

Jim.



 

[MLMartin]

what kind of brick / blocks do you have in the forge, looks like normal concrete, if it is the block will break up and little bits explode when heated

[ThomasPowers]

Doesn't appear to have any sort of *insulating* refractory as such you are trying to fill a bucket with holes in it---you are losing heat as fast as you dump it in.
You have to either pour it in faster than it can leak out or add some insulating refractory---either soft light firebrick or something like kaowool.

Anyplace near you that does boiler repair? Many folks have been given enough scrap material to line a forge when they talked with the boiler maintenance people with a box of doughnuts (or a 6-pack of beer---depending on your situation...)

[Dodge]

You mentioned the blower but what are you using for a burner? What size tube? What size gas orifice? What holds the flame? How much pressure? Looks like you could be losing heat between the bricks and the termite mud. Got another pic straight in the forge? Also, in support of the above statement; I hope those are not concrete bricks
Scott

Edit: I posted milliseconds after Thomas. What he said is what I was referring to...too. You need to fill the gaps B)

[Old Boiler]

Doesn't appear to have any sort of *insulating* refractory as such you are trying to fill a bucket with holes in it---you are losing heat as fast as you dump it in.
You have to either pour it in faster than it can leak out or add some insulating refractory---either soft light firebrick or something like kaowool.



Anyplace near you that does boiler repair? Many folks have been given enough scrap material to line a forge when they talked with the boiler maintenance people with a box of doughnuts (or a 6-pack of beer---depending on your situation...)

Hadn't thought about boiler repair I'll look around.
The refractory is light end. Combustion heater brick. Having said that, the combustion heater that they are used for is capable of bring steel up to cherry red, but I get dirty looks from the boss.

I do have gaps between the clay and the casing. I was hoping that the gaps would not be accessible from the firebox.

Re the blower, I don't know what the jet size is, but it is quite capable of flames over a foot long from each end of the fire box. It is a venturi unit.
After further research I'm considering a different design. I designed this one for longer pieces. A door at each end so I could pass the work through, but given the result a closed end may be more successful.
I also need to reposition the blower to the side to prevent the overheating of the hose.


For a former steel town there is bugger all around to support these pursuits these days,. There is one operating blacksmith shop further up the valley who has been helpful. I'll have another chat to him.

Try again.
Jim.

[Dodge]

 

If its a venturi unit, why does it have a blower?? It is ordinarily one or the other; blown (hence the blower) or naturally aspirated (or venturi). Also, if you have flames coming a foot OUT of the ends, you may not be keeping enough heat IN. Seems weird but you can actually force the heat right out the ends. Try adjusting the flame so the "dragon's breath" just licks out the ends and see if the forge gets hotter. But first, try filling the gaps in the refractory :)

 

[Old Boiler]

It's just called an blower. For want of a better term. It doesn't have forced air induction.
I've turned the flame down with no improvement.

I'll start looking for a better refractory.

[Dodge]

Sorry for the confusion but proper nomenclature is paramount to diagnosis. A blower is a fan of some sorts; squirrel cage, impeller, etc, to supply air to the flame. The tube where the fuel and air is mixed and the flame comes out of is the burner, be it venturi or forced air.

[pkrankow]

Old Boiler, where in the world are you?

I think the word you are looking for is venturi, but I could be wrong. Can you post a few pictures detailing the burner?

Phil

[Old Boiler]

Hunter Valley, Australia. Vineyards, surfing, hunting, motorcycling, 4x4ing, spearfishing etc. Populations growing though.
Oh, and we talk different here.

It is a venturi unit. I simply used the term expressed by the salesperson. It's 40 mm dia. (1 9/16) I don't know what the jet dia is but it is ample.

 

[Old Boiler]

Old Boiler, where in the world are you?

I think the word you are looking for is venturi, but I could be wrong. Can you post a few pictures detailing the burner?

Phil

Hunter Valley, Australia. Vineyards, surfing, hunting, motorcycling, 4x4ing, spearfishing etc. Populations growing though.
Oh, and we talk different here.

It is a venturi unit. I simply used the term expressed by the salesperson. It's 40 mm dia. (1 9/16) I don't know what the jet dia is but it is ample.

[Old Boiler]

Old Boiler, where in the world are you?

I think the word you are looking for is venturi, but I could be wrong. Can you post a few pictures detailing the burner?

Phil

Hunter Valley, Australia. Vineyards, surfing, hunting, motorcycling, 4x4ing, spearfishing etc. Populations growing though.
Oh, and we talk different here.

It is a venturi unit. I simply used the term expressed by the salesperson. It's 40 mm dia. (1 9/16) I don't know what the jet dia is but it is ample.

<a href="http://s725.photobucket.com/albums/ww254/Beerdead/?action=view&amp;current=P1220157.jpg" target="_blank"><img src="http://i725.photobucket.com/albums/ww254/Beerdead/P1220157.jpg" border="0" alt="Photobucket"></a>

[Old Boiler]

Old Boiler, where in the world are you?

I think the word you are looking for is venturi, but I could be wrong. Can you post a few pictures detailing the burner?

Phil

Hunter Valley, Australia. Vineyards, surfing, hunting, motorcycling, 4x4ing, spearfishing etc. Populations growing though.
Oh, and we talk different here.

It is a venturi unit. I simply used the term expressed by the salesperson. It's 40 mm dia. (1 9/16) I don't know what the jet dia is but it is ample.

Sorry about the horizontal image. the programme won't rotate it for some reason.

[pkrankow]

Is that a commercial burner? Is it a burner meant for forges? I am not familiar with that design.

I asked because IFI is represented worldwide with members from over 50 countries.

Phil

[Old Boiler]

It's designed for LPG. I bought it at the local gas and welding supplier with the expressed purpose of heating a forge. They seemed to think it would suffice. I observe that some members seem to use LPG without difficulty, but our LPG may not be exactly the same. Having said that, the blackie that I spoke with made his own LPG jet and venturi setup with good effect.
I've heated some light gauge sheet stainless with it, without difficulty .

Jim.

[Corin]

Yeah mate, that is a locally made Bulgin burner (actually on closer it looks like a copy of the Bulgin), pretty commonly used for prawn cookers, branding irons and the like. It should get your steel nice and red in the open air. I would not think it would draw enough primary air for forge work (where secondary air is starved by the nature of forge design.)

In short, they are a nice little burner, but this is not the best way to apply it. There is something you can try... its a bit radical as far as forges go, but not for this burners intended purpose, being an immersion tube heater in a prawn cooker but trying this should identify the issue.

Remove the burner from the forge, pull it back away, say 50 mm and just hold it there, blowing the flame into the forge, if the burner hole on the forge is big enough, (normally it would be 1.5 - 2 times the burner diameter, but try it anywhay) it will draw air around the flame as it enters the forge, allowing combustion to occur within the forge and not out the ends... by regulating the distance between the burner and the forge, you should be able to control what occurs. This will be more akin to how the burner is applied in immersion tube prawn cookers, where the flame only is blown into a reasonably long, normally bent pipe. whatever happens this is not the best burner for your job.

If this fails, take heaps of pictures and send to me, of all aspects of your build, alternatively, PM me I will give you some details, and we can meet up in Sydney, we will make it work.

To understand what is happening here, you need to know a little about how burners are designed. Primary air is the air drawn in at the jet, it is only a percentage of the air required to react with the gas (combustion) The rest of the air for combustion comes from the air around the burner port (where the flame sits). This is called the secondary air. If you do not have enough of either combustion will be incomplete, and occur where there is enough air. i.e. outside your forge.

With blown or large ported venturi burners (as you will see on most forges), you get plenty of primary air, and the need for secondary air is greatly reduced, hence you get combustion occurring at the burner nozzle inside the forge.

the flammability limits of propane are 2.4%-9.6% Gas to Air. That is to say, for best performance you need approximately 6% gas 94% air for best performance.

Hope I did not go to technical, try what I suggested and get back to me we will go from there.

There are other things that will influence this burners operation, what pressure are you running at?
Regards

Corin

 

 

 

[Old Boiler]

Thanks for then reply Corin.

I have no idea what the pressureis. I regulate with the valve. I haven't been able to get the reg yet.

Re the secondary air. I will certainly try this when I have a bit more time.
Uni just started back so a bit intense currently. Especially for an old fart like me.

The venturi setup of your forge is remarkably similar to the example of the blacksmith I discussed my plans with. When I found the burner that I'm currently using I thought it may be a better way to go. Clearly not.

Just a thought.
If I were to remove the hood from the burner, and feed it into a pipe leading to the fire box, allowing for greater primary air flow, do you think that this would be closer to the desired result?

Jim.

[Corin]

Regarding your mates forge, I may have sold him the gear... I have worked on a lot of forges!

Sorry mate I am not sure I understand which bit you are referring to when you say "hood". However I would not mess with the primary air though, because if that fails you will end up with no burner. You may as well put that burner aside for hand held heating work, and start again.

In your pictures it looks like you could undo the clamp and move the burner back from the hole and fire the flame in. This will definitely work, though your hole may be a little small, I still recommend you try it. I mentioned that this is what we do with Prawn Cookers, it is also what we do with Raku kilns with this type of burner, and they can get up to 1100 C +
Here is a Raku Kiln with this configuration

My link

and another

My link

and another

My link

This is a proven method with this style of burner, and if it is simple to move back it will save you a whole lot of issues if it works with your inlet hole. If not try firing into the bottom corner of your door.
Of course it may not work with what you have, but like I said you loose nothing giving it a quick go.

You may even find that by moving the burner in and out you will be able to adjust combustion.

Anyhow Let us know how you get on.

[Old Boiler]

OK, I now have a silly grin on my dial.

Clearly not yet hot enough but far better than previous.
I lifted the nozzle about 20 mm and got an instant improvement. I'll experiment to tailor it further.

Hope the photos attach, but my 'pooter skills are about as good as my blacksmithing skills.

Thank you Corin!

[pkrankow]

If you have any extra firebrick, I would do a loose stack brick forge till you get a better burner for this shell instead of modifying this shell.

Then again, you have a trip to play in the dirt and other low to no cost items involved, so maybe you are set to play with it and modify this shell to suit this burner.

Phil