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I Forge Iron

Second attempt


Old Boiler

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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!



Great, that is exactly what I was hoping for, but that was only step one, the pictures hold more clues, and we may be welding in this baby yet. (don't get your hopes up, I am optimistic about the termite mud, but it is no ceramic fibre)

The next step is to correct problems with you chamber. Remove all the bricks. There is not enough volume in there for that size flame. That termite mud should work OK on its own, it is not ceramic fibre, but give it a go, I am hoping it will surprise both of us. It can certainly take the heat.

now next is a very important step. your table at the front of the forge should be level with the forge floor. stand two bricks on end on the table blocking the door, leaving about 75 mm gap between them in the center for you to but the steel through. Try and get them up as close as possible to the forge door. This is a crude fix, but let me know how this goes, I can then advise a more permanent solution.

you may need to increase your table size (by clamping something bigger to it temporarily) and remove the swing door so you can get the bricks hard up against the forge.

fire it up and leave it for at least 10 minutes, that termite mud will have a lot of thermal mass and will take a while to get up to temp, probably something like 30 minutes before you reach maximum.

These two bricks do two things that will (hopefully) significantly improve your heating and temperature capacity. Give it a go an let us know how you get on. If you don't get what I mean with the bricks, let me know, this bit is important to get right.

Corin
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Sorry just realised it is open both ends. Block the back end with a fire brick during testing (it will heat a lot quicker, still about 30 minutes to full, but 10 should see you toasting marshmallows. I am guessing here but I want to see what this mud does when it gets hot. I am really curious about this mud and its properties. New technologies work great, but people were forging and even casting steel before asbestos, and ceramic fibre.

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Sorry just realised it is open both ends. Block the back end with a fire brick during testing (it will heat a lot quicker, still about 30 minutes to full, but 10 should see you toasting marshmallows. I am guessing here but I want to see what this mud does when it gets hot. I am really curious about this mud and its properties. New technologies work great, but people were forging and even casting steel before asbestos, and ceramic fibre.



Sorry re the delayed reply. Been off line for a few days. Technical difficulties.

Have not yet given the clay a heat as its been 4o+C for the last few days. Thermometre topped out at 43C.

Will trial it when the weather is a little cooler.

I've located a local source of refractories, but I'll see how the clay goes first.

Talk to ya later.

Jim.
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  • 2 weeks later...

Hi Corin. This is great you helping Old Boiler out like this.
Say, I really like the looks of that burner. Do you feel it's inferior to the "normal" venturi burners we use here? That unit sure puts out a big, nice blue flame.
Are they expensive? I'm hoping that Old Boiler may have run across something we might want to look at. Now I need to get in my ute and go to WalMart and buy some Texas Prongs :D

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Hi Corin. This is great you helping Old Boiler out like this.
Say, I really like the looks of that burner. Do you feel it's inferior to the "normal" venturi burners we use here? That unit sure puts out a big, nice blue flame.
Are they expensive? I'm hoping that Old Boiler may have run across something we might want to look at. Now I need to get in my ute and go to WalMart and buy some Texas Prongs :D


Hi Mate,

These burners are about as simple as burners can be. Look at the range from companies like My link

Harbor Freight, Wallmart, whatever tickles your fancy.

If you listen to all the guru's on the net they will all tell you they won't work due to back pressure... This is not true. In most cases it has nothing to do with back pressure and everything to do with combustion air.

Here is a picture from "Efficient Use of Fuel" Published by "His Majesty's Stationary Office" in 1944

I have newer publications with different pictures but this is actually one of the better pictures I have seen that clearly illustrates what we are talking about in forges.

The text I have added is the amount of air required for a propane burner, the original figures were for towns gas. Methane is natural gas by the way.

flamesmod.jpg


The second burner is almost exactly the same as your harbor freight burners. note that a little more than half the air for combustion has to come from around the flame. sticking the burner in a forge will not allow this to occur, but by pulling it back a fraction and making the hole a bit bigger, air is drawn in with the flame and combustion will occur within the forge. Not rocket science... but sort of... (if this had anything to do with "back pressure" the flames would not enter the hole, in fact we are now adding more air into the forge. It is just a different way to do it)

Now look at the last flame, this is what any well designed natural draft forge burner does (pulls in all primary air), and exactly what a blower (fan forced) burner does. for controllability and ease of use it will always be the best option.

These will always be the best option for forging, but any cheap burner with a decent flame will work if you mount it as Old Boiler has now.

The first flame is the most spectacular of course, and the most useless for forging, though I once used a flame like this to forge a house....

Here is a picture of a steel house being tested for forest fire survival using approximately 100 Gal of propane every minute.

18.jpg
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  • 2 months later...

Back again.

Been playing with some pipe and fittings, using Tweco mig tips.
.8mm burns OK with better diffusion of heat, but still not hot enough.
It scaled the steel, so I moved up in mig tip sizes to try to reduce the oxidisation.
I have used .9mm 1.0, and 1.2mm, but they huff like crazy.

Any suggestions?

Sorry about the side on photo.

th_P4290002.jpg

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I suggest you put the whole thing in the car, along with your regulator, hose and any other equipment you have, and bring it down to my place (Picton) on Sunday. I am absolutely certain we can get it working for you. If you are interested send me a pm I will give you my phone number.


Corin

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I suggest you put the whole thing in the car, along with your regulator, hose and any other equipment you have, and bring it down to my place (Picton) on Sunday. I am absolutely certain we can get it working for you. If you are interested send me a pm I will give you my phone number.


Corin


A fine invitation, but unfortunately I'm not able to accept this weekend.
My daughters home for the week and I will be seeing her off on Sunday.

Another day perhaps, when we both have the time. I work a roster.

Thanks Corin.
Jim
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Back again.

Been playing with some pipe and fittings, using Tweco mig tips.
.8mm burns OK with better diffusion of heat, but still not hot enough.
It scaled the steel, so I moved up in mig tip sizes to try to reduce the oxidisation.
I have used .9mm 1.0, and 1.2mm, but they huff like crazy.

Any suggestions?

Sorry about the side on photo.

th_P4290002.jpg


You need to cut back the tip so it only is about half way across the pipe. I'll post a picture of mine in a little. You need to be careful about cutting so the inner edge remains sharp and does not get rounded over, else the gas will not separate from the surface clean and it will cause some interesting swirls.

I would suggest chucking up a tip in a low speed drill and using a fiber wheel to cut...if you don't have a lathe. You may need a torch tip cleaner/file to debur.

Phil
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  • 3 weeks later...

Back again.

Made some changes.

I relocated the burner port to nearer the rear to eliminate the cold spot. I also angled the port to circulate the flame, which has helped.

I have blown the burner with a vacuum cleaner, which has made all the difference. No huffing and I estimate 1100-1200C which is a yellow heat for the spring steel that I have.
I suspect that the bore of the burner that I made, at 21 mm (13/16) is too narrow to achieve a workable heat by natural aspiration.
The salesman at the gas and welding shop where I purchase the bits and pieces has given me another couple of 9 kg (20#) gas bottles to make a bigger forge, so another one could be in the pipeline (he's an enthusiast as well!). If I do I will try to use larger bore fittings to achieve naturally aspirated workable heat.

I have almost finished a hot cut, and I'll show it when it's done.

The forge is up to functional temp within 10 minutes, and probably quicker if I upped the pressure earlier.


th_P5120005.jpg


th_P5120004.jpg

th_P5120002.jpg

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Finished the hot cut. It's a bit rough, but does the job.

It's secured in the hardie hole by doubling it twice. Took a bit of tailoring to get it tight enough to not pop out, and to be stable.

Makes it easier to work with two hands. One for the hammer, and one for the tongs.

th_P5200004.jpg

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