My vertical forge build

The opposed ports help keep the swirl of flame even and keep the chamber from being hotter on one side than the other.
Melting furnaces are different things and not directly comparable.

You could probably use one large rear port if you wanted to, but there have been tens of thousands of forges built with front and back ports …. with no need to close off one of them.

Personally, I think you are going to have a big problem with all that 2000° steel in the port. I would suggest you get rid of that entry chamber. If you want something there, stack some firebricks to make the igloo door.

There is no real reason to try and re-invent the wheel.
 
Thanks, Stacy. I'm going to need to rethink some things in this build. I was worried about the steel ports getting hot. For what it's worth, I was planning on leaving the last inch of the ports/doors just kast-o-lite by using wood forms:
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If that's not enough, maybe I should cut the metal even shorter?
 
Cast-o-lite is a refractory that heats up and stores the energy. It isn't an insulation. It won't solve the problem of hot ports.
Firebrick is an insulator and will keep the ports cooler.

I am going to ask you to listen to me here. Use firebrick for adjusting the ports. Forget the fancy drop ports and steel entry tunnels. Unbolt them and make a good forge.
You don't have to listen to me, but take a look at the many vertical forges that have been built and see if any have your entry port idea. Maybe there is a reason they don't.
 
I only wish this had been caught earlier (that using rectangular steel tubing for the ports was a bad idea), since it was part of the original plan. I was basing the idea off a build thread I found on another forum. I think posting links to other forums is frowned upon, but this is an image from that thread:
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If they need to go, they need to go...
 
Metal ports that go through the liner are fine. It is the part sticking out past the shell/liner and that drop gate you need to remove.
 
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Ok. The burner tube is also just going up to the edge of the liner, so do I need to do something about this as well?
 
The burner tube (the end of the burner where the flame comes out) slides in the burner port tube (the tube through the shell and refractory). The burner port shown in you picture from the other forum looks like it is placed too high, but that might just be camera angle. The burner port works best if it ends a tad short of the inner chamber wall and the refractory is flared out a bit to make a smooth transition. If it sticks out, the extra will eventually burn off to be even with the wall.om what I could see in your earlier photo of the forge with the wool in place, your burner port tube looks fine.

What I was saying about the metal ports inside is that they won't be a problem as far as exposed hot metal if they only go through the refractory. You don't want them sticking out inside the forge or outside the forge. Exposed steel will slowly eat away from scale though. A protective layer of satanite ( or other protective coating) over the exposed metal is a good idea.
 
I was trying to remember where I got the idea for having the port tubes extend past the forge body. Karl Andersen has a substantial one in the back of his:
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Bruce Bump had them at both ends, albeit shorter than mine. This was also where I got the idea for having a swinging door on the back port:
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And the Ellis vertical forge also has them:
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So other than the drop door in front, I really wasn't trying to reinvent the wheel too much. I just thought this was fairly standard practice. Is there something they're doing differently that makes the heating of the port tubes less of a problem for them? Or maybe they just get very hot and they learn to live with it?

The internet is rampant with people with very little knowledge on a topic (me) trying to argue with very experienced people (you). I don't want to turn this into that. I know that I don't know. But these other builds, at least, were where I got the idea. Because the external ports help make my hearth setup possible, I do kind of want to keep them. So if there's something different about how these other makers pulled it off, I would like to know.

The one nice thing about not welding anything in place for my build is that, unless I'm creating a dangerous situation, I can probably experiment and remove the ports if I decide I hate them.
 
Yes, those ports are OK. I don't particularly like the hinged door on Bruce's forge, but it isn't a serious issue. A small amount of projection isn't a big deal either. The Ellis forge looks like the port is lined with some sort of refractory. I have used ins-board to make ports, BTW, and it worked well. 1/2" Ins-board would be good to line steel ports. The forges shown are also built neat and clean by folks who have built many forges. They know what will matter and what won't.

If you look at the inside image of the forge with the wool in place, you see that the burner port tube and the side port only project inward enough to end up even with the chamber wall once the satanite is applied. That build has a good feature of using hardware cloth as a support for the wool and a base for the satanite.

Your steel drop gate was going to be a big problem, IMHO. The reason I recommend firebricks is you can move them, change the port size,block things, etc. No permanent changes or welding required. Weld a small shelf/hearth on the back port and use fire bricks there, too. This method will allow all the experimentation you want to see how to tune your forge.

I would ask you to consider why you are doing a cast liner on this forge build? Maybe it would be smarter to build it with a good layer of satanite and after learning to use and adjust it make a second one that has a cast liner. Cast liners are great for forges that run for hours on end and for places like damascus shops. The average home forger does just fine with a couple inches of wool and 1/4" to 1/2" of satanite.

One thing that I didn't go into earlier is that the more cast refractory the forge has the bigger the burner needed to heat it up.
 
The forge is now more or less ready, and I've begun the process of heat curing the refractory (It's been drying for about two weeks now after being cast). The cast liner may not have been necessary, but I hope the forge will be more robust and give a more even heat as a result...

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There were some patchier parts in the kast-o-lite, so I touched it up a bit with satanite. I know it might not be needed, but I have ITC-100, so I plan to coat the whole inside as well as the metal tubes with it.

I decided to ditch the metal lid. It seemed unnecessary. For now, I just have a piece of insulboard weighed down with a firebrick on top.
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I also ditched the crank jack and replaced it with a screw floor jack. This allows me to get a better fit between the bottom of the forge body ands the brake drum floor.

I somewhat regret now not placing the burner assembly on the left side. I will want some metal pan, etc. to extend and shield it from any flux etc. that might drip when I move the hot steel from forge to anvil.
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I haven't addressed the metal ports yet, but yes, they do get hot.
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Because of how the forge fits with the table/hearth, I'll need to keep the bottoms of the tubes at least. I will most likely take an angle grinder to them and turn them into shelves, while still preserving the parts that are bolted on.

Edit: last paragraph deleted. It took about five minutes to get a feel for the fuel/air mix. My pressure gauge seems to be faulty, because it's reading zero as soon as the forge starts going, regardless of whether I increase or decrease the propane flow.
 
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Some sputtering is normal at full blast, especially before the chamber gets fully heat soaked … which can take a good 10-15 minutes with a cast liner. It might have too much air (flame looks blue and sputters). Once the chamber is fully soaked, try lowering the air and adjust the gas accordingly.

Always tune a forge after it is hot for at least 10 minutes.
 
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