by Rick Dunkerley
Today there seems to be a damascus maker on every corner, and the opportunity to learn to forge damascus is available to almost anyone. In 2005, the American Bladesmith Society slated seven damascus classes at the Bill Moran School of Bladesmithing. The Sierra Forge and Fire School held several classes, one taught by yours truly. There are numerous “hammer-ins” around the country and most have forging damascus on the agenda.
Be warned that forging damascus is addictive. I once heard Daryl Meier, who I consider the greatest modern maker of damascus steel, say, “Making damascus steel is a disease for which there is no cure.”
In my own shop, I try to keep things simple. By eliminating as many variables as possible, I am successful at making good forge welds. I have developed a routine that I go through with each forge weld, and by not altering what I know works, I’m confident that my welds are going to turn out good.
First in the process of forging damascus is the selection of materials to forge. This is an area that I feel strongly about and I recommend 1084 and 15N20 as the steels to combine when forging damascus. Devin Thomas suggested these materials to me almost 10 years ago and I feel they have been instrumental in my success. First, 1084 is simple steel with .84 percent carbon and .9 percent manganese. The manganese defines it as deep-hardening steel and turns it darker after etching, allowing for more contrast with the lighter 15N20.
As for 15N20, it is basically 1075 with 2-to-3 percent nickel, which results in extra toughness and gives it the quality of resisting etching, resulting in a silver layer almost as bright as pure nickel. This combination of materials welds easily and can be manipulated extensively. Blades made of 1084 and 15N20, if heat-treated properly, cut extremely well and are tougher than nails.
As with my philosophy on knifemaking, I like my forge to be simple—one burner with a small blower to provide air. The forge must be capable of reaching 2,300 degrees Fahrenheit, which is no problem with a properly regulated propane forge.
I use ceramic fiber insulation in my welding forge, which is coated with refractory cement to help resist flux and also to protect the ceramic fiber from damage. Cast-able refractories work well for insulation also. They take longer to heat up, but hold the heat well and shorten the re-heating time of the billet during the forging process. There are many good forge designs out there and my advice is to find one you like and buy or copy it.
For about 12 years I have been using a hydraulic press to make damascus. The hydraulic press has several advantages over a power hammer. For the beginner, the press is much easier to control, and dies can be made for the press that encapsulate the entire billet, making the forge weld much easier. For those with less than understanding neighbors, the press is quieter than a power hammer.
The ability to change dies quickly can be handy at times. The press I currently use was made by Jeff Carlisle of Great Falls, Mont. I have employed a good number of presses over the years and have not found one that I like better. Dr. Jim Batson sells plans for a press similar to the one that Carlisle markets. If you decide to purchase or build a press, I would recommend that it be at least 20 tons and have a good quick-change die set up.
Power hammers embody the traditional blade smith tool and have been used to make tons of damascus. I have used hammers ranging in weight from 25 pounds to 500 pounds at hammer-ins and friends’ shops over the years. Hammers are more fun to run than a press once you get the hang of them. They also distort the patterns or figures in steel billets less often if the operators have good control of them. Bars can be drawn down more quickly with hammers than with presses, and power hammers tend to knock forge scale off rather than forge it into the billets as presses will do.
Whether you choose a press or a power hammer, remember these machines can be dangerous. Combine all the mechanical power with steel that is 2,300 degrees and serious injuries can occur. Always think safety first when operating a press or power hammer.
In preparing a billet for the first forge weld, I stack alternating layers of 1084 and 15N20 to get the desired number of layers in the billet. This may be as little as three or as many as 25 layers for the initial weld. The layer count is tailored to get the desired effect in the finished blade.
I always keep the thicker of the two materials on the top and bottom of the billet, which helps to hold the heat and aids in decreasing warp as the billet comes up to welding temperature. The 1084 comes with light mill scale, which I do not clean off, and 15N20, as I buy it, has no scale and is used as-is.
After the initial forge weld, the billet is reheated and drawn out into a rectangular bar. The size of this bar is dependent on how many layers are desired in the finished billet and the finished size. The bar is then ground clean of forge scale on the surfaces that will be welded during the second sequence. The bar can be hot-cut and folded onto itself during the drawing out process to double the layer count. I have had better success with the grinding and cutting process, but use whichever works for you.
The second weld will progress just like the first, and the number of layers will dictate whether a third, or more, welding sequences are necessary.
These forge welds can be accomplished by using two different methods, namely welding with flux, referred to as a wet weld, and welding without flux, which is a dry weld.
The steps to be followed for a wet weld are:
1 Start with a 19-layer billet consisting of 10 layers of 1/4-inch-by-1-1/2 inch-by-6-inch 1080, and nine layers of 1/2-inch-by-1-1/2-inch-by-6-inch 15N20, which are stacked in alternating layers with the thickest material on the top and bottom of the stack;
2 Clamp and weld one end and then weld a handle on that end. Weld one corner at the end opposite the handle;
3 Place the billet into a forge that is preheated to 2,300 degrees and soak until the billet is dull red. At this time apply anhydrous borax as flux;
4 Allow the billet to reach welding temperature, which is indicated when the flux is bubbling rapidly. Rotate the billet to make sure it is heating evenly;
5 Weld the billet using a press or hammer. If using a press, use dies that are longer and wider than the billet to weld in one squeeze. If using a hammer, weld from the handle end outward to allow the flux to escape;
6 Use a wire brush to remove the flux and scale. Reheat the billet and forge into a rectangular bar, reheating as many times as necessary to reach the desired length and width;
7 Allow the billet to cool and grind any scale off of the billet. Cut the billet into as many pieces as required to reach the desired number of layers; and
8 Repeat the welding process and draw the billet out to the desired dimensions. The process may have to be repeated again to get the required number of layers.
By creating an inert, oxygen-free atmosphere, forge welding can be accomplished without flux, known as a dry weld. This will usually result in a cleaner and stronger weld. This oxygen-free atmosphere can be created several different ways:
1 Make a sheet metal box that the billet is placed into, and then weld the box closed. Spray a small amount of WD-40 inside the box, or place a small piece of combustible material inside, to burn off any oxygen inside the box;
2 Weld all exposed seams of the billet to seal oxygen out; and
3 Use square tubing of an appropriate size to contain the billet.
Forge weld as described in the wet welding sequence, omitting the flux. After the billet is drawn to the proper dimensions, the box or tubing must be ground off of the steel. If it becomes necessary to cut and restack the billet, there are three options. It can be put into a box, the seams can be welded to do another dry weld, or flux can be used to do a wet weld.
The desired visual effect and the pattern will be factors in the number of layers in the finished bar. I prefer a predominantly black-looking damascus, so I like the 1084 layers to be approximately twice as thick as the 15N20 layers. Because of its nickel content, the 15N20 layers do not compress as much as the 1084.
As the layer count increases, the initial difference between .25-inch 1084 layers and .075 15N20 layers becomes much smaller. This initial size difference seems to balance out to the effect that I like at 200-300 layers. Some experimentation with different thicknesses will teach the beginner how best to achieve the desired effect.
The damascus pattern applied to the blade will also be a factor to be considered in the layer count. In my view, random patterns seem to look best with at least 200 layers. Twist patterns do no need as many layers, as twisting the bar tightens them. Fifty to a-hundred-and-fifty layers work well to achieve a twist pattern. For a ladder or raindrop pattern, 200 to 300 layers are ideal and, with a good etch, will give a holographic effect to the blade.
These are by no means the only methods for creating damascus patterns. It is my hope that you will take this information and come up with your own ideas. These methods are meant to be building blocks, and by combining them or modifying them, you may come up with something truly unique.
Once a blade or bar of Damascus has been forged, it must be prepared for heat-treating. The first step is three thermal cycles to relieve stresses imparted while forging the damascus. The thermal cycles consist of heating the bar to non-magnetic and allowing it to cool for several minutes.
This is repeated two more times, and after the third heating, the bar can be allowed to cool to room temperature, which is a normalizing step. This process greatly reduces the possibility of the blade warping during the hardening process.
The blade or bar of damascus is then ready to anneal. It is again heated to non-magnetic and placed in vermiculite to slow the cooling process. After approximately six hours, the steel is annealed and can then be drilled and ground easily.
After drilling any holes needed and grinding to a 120-grit finish, the blade is ready to harden. If the forging was uneven and required grinding one side of the blade more than the other, I recommend several more thermal cycles before hardening.
The hardening process for bars forged of a combination of 1084 and 15N20 goes as follows: heat the blade to 1,500 degrees in high temperature salt; hold for two to three minutes; quench in preheated (120-degree) oil; and the allow the blade to cool until it can be handled comfortably bare handed.
This should result in a Rockwell hardness of 62-64 Rc. Two tempering cycles of one hour each at 400-425 degrees should produce a blade with a Rockwell hardness of approximately 58 Rc. If high temperature salts are unavailable, the blade can be heated to nonmagnetic and quenched with similar results.
This same heat-treating recipe will work for other combinations of simple steels. The tempering cycles should be at a lower temperature (350 degrees) and raised 25 degrees incrementally until the desired hardness is obtained.
The hardened and tempered blade must then be finish-ground and hand sanded so that it can be etched to reveal the damascus pattern.
I grind my blades to a 320-grit finish and begin hand sanding with 400-grit wet and dry paper. The sanding is done perpendicular to the 320-grit belt marks until they are gone. Then 600-grit wet and dry paper is used to remove the 400-grit scratches.