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I Forge Iron

Propane forge, #2


Branstetter

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First firing!

This is my second forge build. The first one I sold to a motorcycle aftermarket parts manufacturer. They needed it to heat and form their springer parts.

This one is made from a 7 gallon propane tank. It was out of date and had the old P.O.L. valve on it. So no big loss.

I cut it in half the long way. I read somewhere, maybe on here, someone's description if doing it this way in order to ad height if needed down the road sometime. I really like the idea of the extra versatility of that so that's how I did this one.

I used Refecrete KS-4 PLUS Castable Refractory Cement. The biggest reason I chose this stuff is the fact that I can pick to up locally for about $52 a bag. It's rated to 2550F so I'm thinking it should do just fine.

I decided to put in three 3/4" burners on this one because it seemed like a good number. And according to the math that should be just a little bit overkill for the volume. I'm happy with that. It's better to have it and not need it rather than need it and not have it.

I'm going to be adding a material rest and some tabs to bolt the two halves together soon. Then slap on a coat of high temp satin black and run it till my arm hurts.
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I promote cutting the bottle lengthwise in my tutorial on my web-site.  It makes it so much easier to cast when everything is lying open in front of you.  I weld common door hinges on each side to hold the two pieces together.  Then if you need to go out the side because of the size of the forging or need to raise the whole top portion you can just knock the hinge pins.

 

Let me know if I can help you.

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WayneCoe, I'll give you the credit for the idea. What you described is pretty much what I remember reading. I just read so much different stuff it's hard for me to remember where I read it. Thank you.

Eseemann, that's the idea. Not sure if it's a good idea or not. Seems to help so far. I can get to welding temps with it. Right now I have .035" welding tips in it! Running a bit rich. I'll be changing them out to .023" to lean it out a bit. That was the change that made all of the difference on the last one.

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Neat forge, Branstetter. Hey, northern Nevada!! I was born in Carson City and still have family friends in Elko :)

 

Jymm Hoffman also makes a "clam shell" style forge. Albeit his has a different kind of burner consisting of flattened nozzles rather than round like we are used to seeing. Been thinking of trying one on my next forge and perhaps the clam shell as well....

 

Scott

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  • 2 weeks later...

So I finally got it finished. Except for the adjustable material rest, I need to acquire some more material before I can put that together.

Made a plug for one end out of a couple pieces of 3000F bricks. Ran it all the way up to full temperature, got a couple wisps of steam during the run but nothing exploded! One thing I'm not too big on is how long this refractory takes to get up to temp. I plan on adding some IR reflective material in the near future, that should help.post-51891-0-41354000-1411865042_thumb.jpost-51891-0-61204600-1411865072_thumb.jpost-51891-0-72019700-1411865118_thumb.j

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I'm not a fan of IR reflective coatings. You want a forge to have "thermal mass". That way it heats stock quicker than the flame alone can do. An IR coating just inhibits the absorption and release of heat from the lining. Cast-able refractories generally tend to be only modestly good insulators. That makes them decent at absorption and release of heat, but not ideal for keeping heat inside the forge.

 

My experimentation so far has led to to favor an inswool (or equivalent) outer lining with castable inner. The thickness of that inner layer is a compromise between forge-heat-up time and large heat reservoir. It could be tuned to match your typical stock size as well. A thick layer for heavy stock that will need lots of heat to get to temperature. A thin layer for small stock that cannot benefit much from a large heat reservoir. You can also adjust this by putting hard firebrick in the forge if there is room.

 

IR coating fans report time from lighting to first hammer blow, not time for an at-temperature forge to heat a piece of hammer stock.

 

It might be that inswool with IR coating + firebricks is the best approach (durability aside), but I plan to make my next forge about 3/8" of cast-o-lite on 2" of inswool. I'd use thicker cast-o-lite on a 3-burner beast like yours.

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