First - I used to wire billets. It is only there for the first few hammer blows, so make sure you can weld well before you try hand.
Second - I would use arc welding to make the tack welds and weld on a rebar handle. This is by far the easiest and best results method. The cheapest welded you can buy will do what is needed to make up a billet. But, if you want no arc welding on the billet, use wire and weld fast but not too fast. You may have failures on your first several billets with wire. In the directions below, I use tack welding to securely stack billets. You can use wiring if you want.
Third - Borax flux ( yes, 20-mule team works fine) is not glue and is there to keep oxygen away from the hot steel. It also cleans the surfaces to prepare for the weld. It melts and covers the surfaces with molten borax glass. It may be tempting to just spoon it on repeatedly, but there can be too much of good thing. The flux may get trapped in the welds causing a flux pocket and bad place in the billet. At welding heat it is very liquid, and when the hammer hits the billet, it shoots out of the layers and from under the hammer like a meteor shower. It will burn whatever and whoever it hits. Have fire protection, a good leather apron on, eye/face protection ... and NO ONE within 25 feet of you. Anyone watching from that distance should still have eye protection on. Look around for things that could light on fire from a drop of borax lava.
This is how I have taught people to forge weld and then to make a simple damascus:
They would start with welding two bars of 1/4X2X12" of 1095 (or any simple carbon steel on hand) together. I would have them make a 2" overlap weld. We tack welded the bars together on the sides like a billet, but wire wrapping would have worked. They would forge that center weld solid. Once ground clean on the sides and welds checked, they would forge the thicker center area square, then round. Once done, they cut the welded area off and tossed it in the slack tub. After cleaning up the two bars left over, they repeated the welding lesson again two or three times. These times instead of changing the shape of the center, they drew the center area out to make a more-or-less even 1/4" X2" bar.
I called this lesson, "The Art of the Weld".
For hand welding a damascus billet in a forge, I would start with 8 pieces of steel - seven pieces 4"X1.5"X.25", and one piece 6"X1.5"X.25". Put the longer bar in the center, so it acts as a handle stub for the U-Box tongs to grab. Hand welding a stack that size will be plenty of work. It will make a final billet big enough to forge several knives.
Again, before tackling damascus, master forge welding (if you haven't already).
Then, on to making damascus by hand in a forge (after mastering "The Art of the Weld"):
Make the billet stack as above and make the first weld. Work the weld well making sure it is solid.
Draw it out to about 3/4" thick.
Grind it clean on the 4 sides and check all the welds. If welds are good, cut in three pieces for the next weld. The three pieces should have the same amount of layered metal with the tong-stub sticking out again. Weld solid as before, cut in three, and stack, re-weld. Repeat one more time.
Starting with the initial 8 layer stack the third cut-stack-re-welds makes 216 layers. That will be a nice random pattern. (If you start with eight layers, and restack in threes you will get 24 layers on the first re-stack, 72 layers on the second, and 216 on the third.)
Once hand welding is easier, you can draw the billet to around 1/4", grind clean, cut into the same number of bars as you started with, stack, and re-weld. This builds layer count a lot faster.
TIPS and TRICKS:
Tip -Try not to bend the extension stub back and forth too much while welding the billet or it will break off at the billet as it gets thinner. You can usually get two re-stacks before the billet falls off the stub. When it does, I just weld a re-bar handle on, but large tongs would work, too.
Cool Trick - To make this a really great looking suminagashi san-mai:
Using A=1084/80CrV and B=15N20 (or similar contrast mix) for the billet. Cut three, 2X4X.25" bars of each steel, and three 6"long bars from the 15N20. Stack A-B-A-long B-A-B-A. Weld up the stack, and draw it out to 1/4". Cut the stub off and cut the layered bar into six pieces. Clean up for welding. Stack with a longer piece of 15N20 in the center, re-weld, draw out to 1/4", clean up, cut into six piece, restack with a new center. Weld and draw out to 3/8" thick". When drawn out, brush clean, heat to forging heat, and work the surface pretty heavily all over on both sides with the ball end of a heavy ball-peen hammer. This will make a 343-layer highly random billet.
Cut the billet in two pieces. Cut two pieces of .060" 15N20 the size of the layered pieces and one piece of 3/32" Pro-cut. Stack in this order - layered-15N20-Pro-cut-15N20-layered. Weld up solid. Draw down to around 1/4", and grind clean. You should have a heavily random billet with 689 layers. This will make several really nice looking and cutting knives.
Now to make cool stunning!
NOTE - All hammer work in this next segment are done at forging heat.
These procedures work best on a wide blade like a gyuto, nikiri, or santoku.
Make a wave-pattern forging hammer. Take a cheap 2# mechanics or forging hammer and grind one face as a vertical 3/8" radius, and the other as 1/2" radius. Round the edges a bit so it does not make divots. The result is a hammer with the faces resembling two half-cylinders. Sand smooth to 400 grit. Buffing is also good. This hammer will leave smooth and even curves in the blade edge. Use both hammer sides as desired to vary the depressions made.
Mark the profile of the knife desired and cut it out from the billet. Make the edge a little short in width, as you will draw it down some in the next forging steps. Grind this profile clean along the edges.
With a regular hammer, forge down the edge to make the bevels. Forge in some distal taper, leaving the blade edge about 1/8" thick at the ricasso, and 1/16" thick at the tip. The spine should be a little bit thicker than the edge. No need to get crazy about finish forging as you will do more hammer work, then grind the blade smooth.
Wire brush well, and hold the blade flat on the anvil so the edge is right at the edge of the anvil face, but not overhanging. Use the wave hammer to forge down the edge, slightly overlapping each blow so the centers are about 3/8" to 1/2" apart. Return the blade to the forge as often as needed to keep the blade at forging heat.
The spacing should vary a bit. Angle the blows so each blow deforms the edge area about half the edge thickness, and tapers shallower as the dent goes up the bevel. Make some longer than others, varying from 1/3 of the bevel height for the shortest to 3/4 of the bevel height for the longest. Switch from side to side on the blade as you forge divots toward the tip. Use both sides of the hammer, switching every few blows to make the widths vary. Make them overlap more as you go toward the tip, finishing the last inch or two with only the 3/8" side of the hammer. To make sure you understand - the hollow curved groove goes from the edge toward the spine., it is perpendicular to the edge and tapered so the hollow will be deepest at the edge and taper off to nothing about half way up the bevel. You will get the hang of how hard and how much angle after with a few blades.
Straighten the edge and blade as needed with a regular hammer, taking care not to forge out the depressions.
Normalize and do a DET anneal on the blade.
Grind the knife from this manipulated blank. As the material is removed in grinding, the manipulations will show as a wave in the pattern of the suminagashi along the 15N20 faux-hamon. The 15N20 line will now wander up and down like a crazy hamon, with the suminagashi following along the border. The same procedure can be done with regular san-mai to get the reticulated line look.
The cool thing is that there will be a descending order of finer bright lines in it, with the widest before the core steel edge, and the layer of 15N20 looking somewhat like a hamon.
