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First I have to talk about the guys in the California Knifemakers Association (Cal Knives) club who have been forging Damascus for a long time and have helped me to learn the art of forging. I started to forge using other people’s forges in 1997 at a hammer-in put on by the Cal Knives. Well, like a lot of people, I did not have a place that I could set up a forging area at that time but still would take time to go to other knife makers shops and pound on a piece of cable or 1095. I still am learning how to forge weld and forge but now I do not need to use other people’s forges.  The Oak Tree Forge design came about in early 2004 after 2 months of looking on the Internet and sending out e-mails to a lot of knife makers about the best forges available on the market.
Some of the problems that I saw with most of the forges that I used was that they were just Kaowool lined and were very soft and susceptible to damage from poking steel billets into them or were cast solid with no Kaowool to insulate and keep heat in. All were rigged with a blower system of some sort. When it came time to set up a forge area in my new shop I was still looking for a better forge; one that had a cast liner with insulation between it and the outside shell. I found one unit that was a cast refectory with one burner opening but it was just a liner and you had to assemble the rest yourself. Having about 30 + years experience designing and developing products and processes for other people I said to myself, “I can make one the way I would like it to be”. So, in 2005 I started to build the masters and molds of my design, the Oak Tree Forge. There is an old Oak Tree in my yard that is truly an exceptional tree. I will post a photo soon. In my travels through the Internet in 2004 I came onto the T-Rex burner and his big brother the 1” Forge and Foundry burner. This was the thing that got me really going on the Oak Tree Forge. Here was exactly what I needed to make my design be the best forge, from my point of view. The word got out and some other people heard about what I was doing and got very excited and helped a lot to get me over my lack of experience. One was Ron Riel who is the man when it comes to forging and burners. He also helped Rex Price develop the Hybridburners. So check out there web sites via my WebLinks page to learn more.  I designed the liner of the forge to be split into two halves, an upper half that the burners are in and the bottom half where the replaceable tray lays to make a flat floor in the forge. I used a 6” inside diameter by 18” long inner chamber. The doors are hinged on the left or right depending on the end you are standing at, this way one can decide to open from the left or right. The doors have a latch type lock that has a ramp for closing. The door hinges have bronze bushings that are 2” apart for smooth action. The standard forge design has the burners/plumbing on the hinge side as seen in the photos. The burners/plumbing can be ordered to be on the opposite side.
After some testing using a solid cast piece in the door it was clear that a split door was needed so the production forges will have a split door casting as well. The door has about 1 1/2” of Kaowool behind the cast piece and between the steel doors. There was much talk about how big to make the door window, so I decide on 3” X 4” split on the horizontal like the liner. When I cut the Kaowool for the liner I make it a little bit long so a little will hang over past the casting where the door hits when closed, that way I get a seal at the door. I spray on a coat of ITC 100 on the inside of the liner, door face and replaceable bottoms. The out side will have a powder coat of high temp (600F+) flat black paint on it. The legs and brackets are water jet cut from 3/16” steel, as is the body of the forge. I have a lifting lug added to the burner support to make it easier to lift the forge. I recommend removing the doors before lifting to move the forge. There is an adjustable support that can be used on either end to support handles for billets or long steel bars, if not needed it can be flipped over and stored in the down position. I had designed a table for welding some years ago from angle iron that uses high temp brick as a top. This is the best type of table, it gives you a place to set hot steel when cooling, and it just keeps the heat off the table itself. Just make a table strong enough to support the forge and the bricks. Some time soon I will make a dedicated forge table that is a little taller so I don’t have to bend over so much to look inside. As you can see in the photos I have an extra brick under the forge as is and it is still to low for me. Another thing that I have cast in refectory is a door plug, it helps to heat up the forge to forging temperatures and I have used it to run one burner for blacksmithing.  The T-Rex burner is the centerpiece that I designed the forge around. I like the fact that they do not need a blower to work. After some math and consultation with Rex and Ron it was decided to use the T-Rex (3/4”) burners as the standard for the forge. I have been doing some work with a forge that has 1” Forge and Foundry burners, more on that later.
One thing that I can’t stress enough is the need to CLOSE the chimneys or air chokes after you have turned off the gas. The Tweco tip will be overheated beyond its limits! This could affect the performance of the burners the next time you use them. When lighting the forge I get all the valves open EXCEPT the main and burner valves, I set the choke at about half open. Set the pressure on the gage at 6 psi. I use a small piece of news paper waded or twisted and hold the paper in a tong, light the paper, and lay it in the bottom middle of the forge still in the tongs, turn on the burner valves, After they light you are now running on the idle setting. Pull out the tongs with the paper that most likely will still be on fire or smoldering dunk it in your water tub or step on it to get it out. You can start the forge on the full setting but it will start with a lot higher pressure. This sometimes will blow out part of the burning paper somewhere in the shop or if you are outside it may get somewhere you don’t need it. I have seen and had to put out fires which can mess up an otherwise good forging day. After it lights and you have removed the paper you can turn on the main valve and set the pressure to around 6 to 8 psi. Check the flame for shape and color and if needed, set the choke and or tip to get the best flame. Refer to the Oak Tree Forge setting section of the first time assembly and settings guide. Or refer to the Rex or Ron’s web site for settings. The thing about a cast liner even with a coat of ITC 100 it will take longer to heat up then a Kaowool forge so one must have patience. After you reach temperature you can cut down on the gas to about 2 to 3 psi. This is true for both cast liners and Kaowool lined forges the big difference is longer life of the cast liner. Instead of down time to replace the Kaowool you could be forging. Always be safe when working around natural gas and propane forges. Check often to ensure you do not have any leaks! I keep a small jelly jar of water mixed with half a teaspoon of dish soap and a cheep 1” brush. With this I always check for leaks as I pressure up my gas rig, even after I get it running the first time, I check all the fittings past the burner valves there is not a lot of pressure out there but why waste the gas. |
