Vertical forge build.

[trogdorr]

So last weekend I decided I would try my hand at building my own forge. I was tired of my thinner knives sagging in my horizontal forge as well as the lack of space. So why not build a larger, vertical forge? (I am pretty new to this whole knifemaking/blacksmithing thing so constructive criticism is welcomed) The knives would be straightened by gravity and I could also evenly heat larger blades like machetes. I plan on this forge being used primarily for heat treating. most of the materials I used were available at the local hardware store. I used two Ron Reil style burners consisting of a 1 1/2"-3/4" inch bell reducer, 3/4" tube, 3/4"-1" bell reducer as a flare. the jet hole is about 0.05". For the container I used a 30 Lb propane tank. The burners are connected by a series of 3/8" pipe and connectors to a Mr. Heater 0-20 psi regulator.

Pipe layout

Burners connected to regulator

Top cut off of the tank

At this point I cut out two holes just big enough for the shaft of the burners to fit through

I tested the burners at this point (with the paint on, I know. Smart huh?) there seemed to be very little burn going on inside of the tank and there was a large column of fire coming out of the top of the tank. I figured this meant that there wasn't enough oxygen inside of the tank for the burners to have an intense flame. No pictures of the test, sorry. I thought about cutting one hole in the side of the tank to let in more air, the problem i saw with that was that one burner might receive more air than the other.

So to remedy this I cut two holes to the side, but not quite perpendicular to the burners. Say... 45 degrees..ish

The extra air flow definitely helped with the burn

To regulate the airflow I made a track out of some grooved horse shoe bar stock. Then using the propane tank as an anvil of sorts I curved two pieces of a lawnmower blade to fit in the tracks. I drilled and tapped these curved pieces so I could use set screws to hold them in place. I then welded and assembled the track onto the tank.

Now all that is left to do is insulate it. I was thinking about using that wool type material. This is my first time doing anything like this and I know there are a few different types, so is there anything that you guys have found that works particularly well? I have next to no idea what I should be looking for or where to find it so any advice would be greatly appreciated.

Thanks for looking, let me know what you think.
Trogdorr

 

[DAMNENG]

What you have will probably work fine once insulated. You may have hot spots in front of the burners, so just move the blade to one side or the other.

Just some thoughts:
Heat rises, so if your burner inputs are in the bottom your good to go. You don't need to tilt the burners toward the outlet, the flames don't have any other place to go but toward the outlet.
If your burner flames enter the cavity inside of the insulation at a tangent, this will set up a vortex and pretty well even out the temperatures.
Jim A.

 

[Stacy E. Apelt - Bladesmith]

I don't think you understand how a forge works.

There is no port with a damper to control air input. the air in comes from the venturi in the burner.

The burners should be angled so the flame runs along the sides in a swirl, not straight across the chamber.

As said by Jim, the burner(s) should be towards the bottom. Most vertical forges only need one burner.

I'm not sure why your blades are all sagging, perhaps you are running your forge too hot? Making the forge vertical will not amend for too hot a chamber.

Most vertical forges are not used from the actual top like your build. There are ports on the sides at the top. The flames heat the chamber from below and come out the ports. This is very good for larger billets in damascus welding.

Those pipe bushing flares on your burner tubes won't work all that well and will be burned off very soon. The burner flare is a piece of expanded pipe that is also heat resistant.

Burners usually are slid in a burner port tube that allows the burner to be moved in and out to get the right flame. This also allows re-building of the burner as needed. If you build them in permanently, you will have big problems later on.

I think you should look at some forge build threads and photos as well as read all the FAQs and info on High Temp Tools and Refractory's site. www.hightemptools.com

 

[Atlas Knife Company]

You shouldn't use white teflon tape with propane. It should be yellow, gas rated PTFE.

Second, as Stacy inferred, you've built an aluminum can melting foundry instead of a vertical forge. I'm betting you're thinking of a salt pot, which would be crazy at your experience level. Please don't try to build a salt pot. Please.

Third, the main burner tubes aren't nearly big enough for a .05" orifice. You need 1" or larger to support the 28.6 CFM of air required to fuel 180K BTU per burner.

Fourth, you've made a good start on a larger horizontal forge. Just build some legs and put it on it's side. Make sure to coat the inswool with refractory.

 

[trogdorr]

you guys are absolutely right. I don't really know what i'm doing. I did use yellow gas tape. the burners are not fixed in place yet, so they can be angled however I want. I probably am running my forge too hot if you think so. i had a smaller drill bit but that broke. so i used one a tad bigger. i see now that was a mistake.

i didnt realize there was so much criteria to building a vertical forge. but with all that said, with a few minor changes, is there any reason this shouldn't work? i would hate to spend all this time on it and end up scrapping it because its not a professional quality piece.

thanks for the replies,
Trogdorr

 

[Stacy E. Apelt - Bladesmith]

I second Charles' idea to add some feet and make a good horizontal forge.

Most of what you have done is salvageable. Take out the burner tubes and weld on 1.5" pipe sleeves at the proper angle to make the burners sit at a tangent to the chamber when lined. There should be three positioning bolts that hold the burner in the tubes (look at some forge photos). Position and angle are discussed in depth in the stickys and the forge building threads.
Put a floor of bubble alumina or castable refractory in it.

Cut a small back port about 3" round. This will allow a long blade to pass through the forge. It can be blocked with a fire brick to keep the forge really hot when welding.

As to your burner, I would just change it to a blown burner, which will use the 1" pipe you have. You will need to change the venturi ends to a mixing chamber and gas entry, but that won't cost much. Of course, you can rebuild the existing venturi jets and they will be fine. Just take the pipe the jet hole is in out and drill/tap it to fit a MIG tip (usually 1/8NPT, but some are metric). Use a .030" MIG tip.(#30). You can change them to larger or smaller tips as needed to get the burners to run perfect.
If you keep it as a venturi burner, take off those bushings and get some regular flares, or just run the pipe straight. IIRC. HTT sells the flares.

Take where the "air damper" hole is now and put a ceramic TC sheath in that place when lining the forge. You can mortar it in with satanite. The tip should stick to just shy of the center of the forge.

 

[Atlas Knife Company]

Just to show what a working vertical forge looks like, I dug this old thread up. You can see how it's very different from what you are building. However, what you have could be converted to a vertical forge. However, none of the reasons you listed are resolved by a proper vertical forge. BTW, a single 180K burner should be adequate for your forge.

http://www.bladeforums.com/forums/s...g-designed-Norris-built-forge-at-Ashokan-2006

 

[trogdorr]

So I decided to take what I had and turn it into a horizontal forge. I used 2 inch inswool and satanite for insulation and a firebrick floor. I did away with the bell reducer flares, instead I heated up the pipe its self and flared it with a ball-peen hammer. I drilled and tapped some tube to hold the burners and welded it onto the body at an angle so I would get some circulation. I still have to make a door for it, I checked and a 10 inch stainless steel frying pan would be perfect so ill have to look around for a cheap one. anyways here's what I have so far..

[video=youtube;3mjjdiaHwhc]https://www.youtube.com/watch?v=3mjjdiaHwhc[/video]

I'm going to throw a door, some heat resistant paint, on it and probably some chokes for the air intake of the burner.

Let me know what you think, and thanks for looking.
Trogdorr

 

[trogdorr]

Oh and I rebuilt the burners with a smaller orifice, and covered up the airflow holes in the body

 

[Josh Rider]

Nice job!

 

[Brian Ayres]

Don't do a door. I have one on two of my forges and it's a pain. Instead mount a 12"x18" flat steel plate at the front. This will allow you to easily stack fire brick to open and close the forge as well as allow a resting place if you have need to set tongs down, or do any forging of long pieces of bar stock.

 

[Stacy E. Apelt - Bladesmith]

Without a rear port, you still need the front open at least part way. Do the firebrick stack like Brian suggested.

 

[trogdorr]

It got a paint job earlier today. I'm thinking about painting flames on it, you know, to make it burn hotter.

I like the idea of having a place to rest things, though I don't have a bunch of firebrick laying around. If I cut a port in the door would that work? It would still have a place for the gas to escape while the hatch is closed, and I can have things hanging out of the front of the forge. I still would put a rack of sorts for long work pieces but I'm pretty set on this door idea unless there is a major advantage one way or the other. My dad has a farriers forge with a door and I don't find it to be too much of a problem. But then again I never have to use it really because I just use the side ports.

-trogdorr

 

[Stacy E. Apelt - Bladesmith]

As long as there is a port for the combustion gasses to escape from, a door is OK. What I was saying is not to make a solid door. A 3X3" port is enough for most forges. If the port isn't big enough, you will know, because the burners won't work right due to back-pressure.

What many people do is build a front shelf on the forge. Then they stack firebricks as desired to make the port any size needed. For HT, it can be very small, for horseshoes - wide, and for blades - narrow.

 

[Atlas Knife Company]

Not sure what paint you're using. Rust-oleum high temp engine enamel, rated for 2000° F can be found at Wal-Mart. It will smoke a little when it first heats up, then turns to a nice ceramic coating. Don't trust the 500° F paint, it won't hold up to the forge temps.

 

[trogdorr]

I used rustolem pain from home depot, the can says its rated up to 1200 degrees. One of the reasons reason I want a door instead of a stack of bricks is I'm going to be taking this back and forward a bit and I prefer that it be all one piece. I do like the idea of an adjustable port size though.

 

[Stacy E. Apelt - Bladesmith]

A door can have a sliding front port. Use ins-board for the sliding door and the inner insulation on the main door.

Just weld a top and bottom "U" channel over/under the main port. Two pieces of ins-board can be slid in and out tom open or close the slit as needed. When transporting or storing, close then all the way. The main port can be full width and about 3-4" high.

Look at some of the forges you will find online. You will se several sliding ports.

 

[trogdorr]

Finally got a door on this thing. I just cut off the bottom of an old 20# propane tank, cut out a port big enough to fit what I need, fit with 2" inswool, and welded on the door with a hinge so it would open horizontally. The hinge took some modification to fit a rounded surface. I had to test it out so I forged a simple latch to hold the door shut. I'm going to put a layer of satanite on the inswool exposed through the door to protect it from getting tattered. For now I just have to be careful. I am very impressed with how it performs, especially with this being my first forge build. It takes a minute to heat up but once it does it can have it on so low it almost sputters and it still stays really hot. The circulation heats the forge evenly and keeps any hot spots from forming. I can get a solid heat and a half after I shut off the propane. I see this forge serving me very well in the future and I will be sure to let you guys know what creations come from it.

[video=youtube;37dM6StlAvw]https://www.youtube.com/watch?v=37dM6StlAvw&feature=youtu.be[/video]

Let me know what you think, I am eager to hear your responses.

Thanks for looking,
Trogdorr

P.s. I know my welds are ugly, don't make fun of me :thumbup:

 

[Atlas Knife Company]

Looks solid, and possibly too hot. I was taught that yellow metal is a bad thing when bladesmithing.

 

[NickBoyle]

Looks a bit too hot. Try dialing back the pressure. Propane is expensive! Don't wanna waste it and ruin your steel at the same time.