Forge Muffle?? And Forge Build WIP.

[KnuckleDownKnives]

I'm in the process of building a gas forge. I'm going to be upgrading my muffle in the new forge as the one I have is too short and on the thinner side of what I'd like and also was originally galvanized. I took it outside and heated it to bright red for about 30 min to cook off the galvanization. I'm thinking of buying a couple feet of 3" OD DOM tubing with a .375" wall. I've seen a lot of posts where people use .25", do you think the .375" is too thick or better? And do you think it will give me a more consistent/even heat? I think the 2.25" Id will be nice so I can HT larger blades. Oh, I'll be using this for HT mainly for now, but will be getting into forging, but don't think I'll need the muffle for that. I really want to dial in on my HT, I've got a PID and thermal couple from Auberins, and the rest of the controller parts are in my mailbox as I write this. I still have to build the burner and get all the gas valves, solenoid and regulator. I'll be able to run this manually or with the PID controlling it.

Anyway thanks for your thoughts.

 

[jdm61]

When I was using a muffle, I just picked some basic 3 inch "black iron" pipe from HD. What I did was remove one of my full sized burners from my Chile Forge Habanero and use the smaller 1/2inch burner by itself once I got up to heat.

 

[Stacy E. Apelt - Bladesmith]

The greater the mass, the better the evenness of heat distribution to the blade. Go with the .375". Let it fully soak for 10-15 minutes and place blade inside. If you lay a TC in the muffle next to the blade you will be reading the exact temperature of the blade.

 

[KnuckleDownKnives]

Getting some progress made today. Just need to fit the door up and make some ledges to hold the fire bricks at each end and the forge body itself will be done then on to the burner and gas pluming and wiring up the pid controller.

Oh and coat it with satanite.

 

[KnuckleDownKnives]

Got the door welded on. The hinge is from the tracking wheel of an old industrial meat saw.

 

[3fifty7]

Looking very good, what's the burner specs gonna be?
Also, if I'm looking at it correctly why is the burner going to be offset to the rear?


Sent via telegraph with the same fingers I use to sip whiskey.

 

[KnuckleDownKnives]

Thanks. It's offset as close to the tangent of the interior and at a 30* angle toward the front so it gets a real good swirling heat. Stacey recommend that's how I build it. Considering he has more knowledge in his pinkey about knife making than I do, I took his suggestion. I'll be using a 3/8" thick muffle tube for doing HT so I should get a pretty even temp through out. As far as the burner, I'm probably going to by a ventury burner from high temp tools and run it on a PID set up or at least use the PID and thermal coulple to get an accurate heat.

 

[KnuckleDownKnives]

Got the latch on for the door this morning. Made good use of an old hyme joint I had laying around.

 

[KnuckleDownKnives]

Think I'm going to add another thermal couple tube closer to the front so I can either move the thermal couple closer to where I'm heating or possibly add a second thermal couple so I can take multiple temp readings.

 

[stezann]

it is coming out nice, but if i got it right it looks like you are having the burner entering near the back of the forge...
Please consider that the end side will be hotter and if the heat is uneven you shall promote having the ricassos hotter than the tips of your knives.

 

[Stacy E. Apelt - Bladesmith]

Stezann,
Because he has the rear closed, the flame should be aimed toward to open port to allow the swirl effect and the exhaust gases to exit without turbulence.

If he had a rear port, placing the burner in the front would be OK.

 

[KnuckleDownKnives]

Got my burner built. It's built like the Venturi burner from high temp tools. Having problems getting it to stay below 1516*. I currently have it set as low as it will hold a stable flame with out pulsing. Going to try to find a pressure gauge when my wife gets home with the truck as I'm not sure what pressure my regulator is putting out. I have it set as low as it will got. I out a metal slide gate on the air inlet and it looks like I'm getting a more yellow flame than blue, but I'd I open the gate up to clear it up the temp is way too high. I'm using a .030 Mig tip for the jet. Any ideas? Is my burner too big?

 

[KnuckleDownKnives]

Ok so got it dialed in. Got a new 0-30 psi regulator and a gauge. Let's just say I'll have no problem getting to forging temp. Maintaining 1500* at just over 1psi and choked way off. Got a real nice swirl with the burner location. It'll M even better once I get some satanite.

 

[KnuckleDownKnives]

Finally got the forge lining coated with some satanite and it's helped out a lot and getting a much better swirl with the flame. Just a note, the forge had only been lit for about 30 seconds before I started filming. The hot spot you see goes away when it's up to temp, but you can't see the flame when it's up to temp so that is why I filmed it like this. Once the forge it fully preheated I have a very uniform color front to back. Running from 5 PSI to about 8 PSI, with a 30 PSI regulator.

 

[nateman_doo]

Put your camera closer. much closer so we can see better inside

 

[kuraki]

That's looking good Marc.

I'm building my new workhorse right now too, but going with a blower because I've never been able to get my venturi burners as dialed in as you've got there. Nice job.

 

[KnuckleDownKnives]

Put your camera closer. much closer so we can see better inside

I actually had my phone zoomed in some, I'm not quite as close as it looks. Way too hot.

That's looking good Marc.

I'm building my new workhorse right now too, but going with a blower because I've never been able to get my venturi burners as dialed in as you've got there. Nice job.

Thanks John, it's been a fun project. It actually runs even smother than the video, except I had a fan blowing in the corner on high pointed over the top of the forge to circulate the hot air coming off of it so I didn't melt the roof. Still need to get my steel roofing installed. Think I'm going to build some sort of hood over it as well. One I can vent the heat out in the summer and can circulate the heat around the shop with in the winter.