Trouble with gas forge

J

JamesP007

Joined
Jul 19, 2020
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7
So, I have this mini gas forge, and the burner creates a circle in the center that doesn’t actually get hot. Not only does the floor of the forge not get hot in that area, but metal doesn’t either. Because of this, I’ve had to start keeping things on the sides. How do I fix this issue with the burner though? I want to be able to use the full floor of the forge.
 
A bit more detail would help: ideally a photo or 2 of the whole thing showing the General Arrangement.

There are an almost infinite number of possible forge designs/configurations. If you ask a fairly broad question like yours, the likelihood is that you'll get a lot of responses along the lines of "I had this problem and you need to do this. It worked for me", when the rest of their setup was so different to yours that their fix just won't work in your case.
 
Without more detail on your "mini forge" it is hard to tell what the issue is, but the following may help.

The center of the flame from a torch is a void. The center of the circle you see is that cold void. Pulling the torch back a bit may help. If your burner is not properly placed or running too high it will create a cold spot. Having the flame enter the chamber at a tangent and swirling around the sides helps eliminate this. A proper burner with a suitable length burner tube or a mixing chamber will also help.

Sadly, on a mini forge run by a torch (2BF, etc.), the cold spot is hard to avoid. Building a larger proper forge is the cure. It doesn't have to be huge, just round chambered and have a proper burner.
 
timgunn1962 said:
A bit more detail would help: ideally a photo or 2 of the whole thing showing the General Arrangement.

There are an almost infinite number of possible forge designs/configurations. If you ask a fairly broad question like yours, the likelihood is that you'll get a lot of responses along the lines of "I had this problem and you need to do this. It worked for me", when the rest of their setup was so different to yours that their fix just won't work in your case.
Click to expand...
I wanted to post a picture but I could figure out how to do it. It wanted me to upload a URL. So how do I upload a picture from my phone? Obviously I’m new to this site
 
The info on posting photos is in the stickys, or use the custom search engine to find the info. You are a registered member and can't post without the image on a hosting site like pictura, imager, or another. A paid membership allows posting from your phone or computer.

If you still can't work it out, email me the image and I'll post it.
 
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Y’all fixed it for me. I needed to move my burner up some in the chamber. Not the cold spot isn’t nearly as cold. Thanks!
 
Angling the burner so it swirls is good.
Also, try pulling the burner out away from the chamber a bit more. On many mini forges, the burner end is about 1/4" outside the burner port. What type of burner are you using?
 
Usaly this is a problem with using to big of a burner for the cross sectional area of the forge. If you moved to a smaller burner this would mostly go away. If going smaller did not put out enough heat then you could switch to 2 small burners. A larger diameter burner tube makes a much larger flame which is much longer. If your flame is impacting the side wall to much then you are actually blowing air and unburnt fuel on that spot kinda. It has not had a chance to fully combust yet by that point. It’s the same reason when using a propane torch you use the end of the flame. If you put the part to close to the exit then it has a hard time heating it up. This is on of the amazing things about ribbon burners. The flames are so short that you get full combustion within an inch or so.

does your forge have a hard time reaching temp? Also what is your gorge diameter and burner tube diameter?
 
JTknives said:
Usaly this is a problem with using to big of a burner for the cross sectional area of the forge. If you moved to a smaller burner this would mostly go away. If going smaller did not put out enough heat then you could switch to 2 small burners. A larger diameter burner tube makes a much larger flame which is much longer. If your flame is impacting the side wall to much then you are actually blowing air and unburnt fuel on that spot kinda. It has not had a chance to fully combust yet by that point. It’s the same reason when using a propane torch you use the end of the flame. If you put the part to close to the exit then it has a hard time heating it up. This is on of the amazing things about ribbon burners. The flames are so short that you get full combustion within an inch or so.

does your forge have a hard time reaching temp? Also what is your gorge diameter and burner tube diameter?
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I am using a forge that I bought. Can’t remember the name, but it is a single burner forge. I don’t remember the dimensions but I’ll update you on those later.

I moved the burner up in the chamber and it made the cold spot smaller, but not completely gone. I run the forge at about 10psi from beginning to end. It heats up fairly quickly and stays nice and hot. I can’t block up the back though, because then the flame starts sputtering, not matter how much I open the choke.

should I be running it at 10psi? I’m honestly more learning on my own as I go than I am by looking stuff up so‍♂️
 
Stacy E. Apelt - Bladesmith said:
Angling the burner so it swirls is good.
Also, try pulling the burner out away from the chamber a bit more. On many mini forges, the burner end is about 1/4" outside the burner port. What type of burner are you using?
Click to expand...
Don’t think I could angle it. And I’m just using the burner that came with the forge. I bought the whole setup. Came with the forge, a brick, lining, the burner w/ choke, and a regulator w/ the hose. The only thing I got extra for it was some satanite to seal up the refractory lining. But I applied that wrong so I’m waiting for it to all break off so I can do a new coat
 
Was it an Atlas Forge mini?
atlas_stainless_mini_forge_july2018-600px-300x300.jpg

If it is, move the urner in and out until it runs smoothest. 10psi is about right, but try some different pressure settings from 5psi to 20psi. Adjust the choke in tiny amounts to get the flame at its best color and smoothness. Once it is set right it should stay there.
 
The dragon's breath ( hot gasses/flames coming out the front and back of the forge) will change from blue to clear to yellow as you adjust the air/fuel mix. Blue is too much air. A lightly blue flame is OK, but you don't want a roaring blue flame like a jet taking off. Clear is neutral and is good. Yellow is too much fuel, and a little yellow is what most folks shoot for. If the burner is burning efficiently and there is just the right amount of gas and air, the dragon's breath will be mostly clear and not overly large. Start with a lower flame with the gas pressure at a lower amount. Adjust the burner position to run smoothly at that pressure and adjust the choke to get the best color flame. You can also hear when the burner is running smooth. raise the pressure as needed to get the forge at the desired temperature. Once the burner position and choke is set, they should only need minor adjustments, or none at all as you raise the pressure.
 
Not one of my forges, sounds like a single burner Hell's Forge or similar with a straight down burner. On top of what Stacy said, you will want to run it on low heat until it completely dries out, or "soaks" as it is commonly called. When a forge cools down, it absorbs moisture from the atmosphere. When you light it, the moisture turns to steam, which causes it to run poorly for a while.
 
I just got one of your Graham forges a bit ago. Still need to fire it up for the first time.

I was wondering, with the blown forge, and the thermocouple, can I run the forge adjusted to stabil Temps at different temps?
 
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