I was unsure if my forge was reaching welding temps and didn't have a thermocouple. So, I went to the pottery supply store and bought a box of pyrometric cones. There are a number of different ones on the scale and the tip of them begin to droop or fall over at a very specific temperature. I got the hottest ones and put it in the forge and turned things up. They worked great to give me assurance I was getting hot enough.

I haven't used them since, and haven't had any problems. I was fortunate to be with someone experienced the first few times I tried forge welding and learned a lot from him. After that, I've managed to be successful at gauging the temperature correctly. When the billet begins to "disappear" in my forge (looks a LOT like the surrounding interior), I know I'm pretty well there. I take it out and quickly to the anvil for some light taps down the billet. Once you do it a few times, you can definitely tell the feel and sound once things have solidified (welded).

That's pretty over-simplistic, but some valuable things I learned. If there's anyone nearby that can help you, it's worth having them there or going to their shop. I'm sure many have started out on their own and been successful. But, I'm willing to bet I'd have less success without the guidance I got early on. Good luck with it and have fun <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' />.

Jeremy

|quoted:
Should I just dive in head first?

Yes.

Since it your first, I'm assuming that you don't have a press or power hammer. That said, keep the billet manageable, ie. small. A billet that is easily worked in a press or even a hammer is impossible to draw out by hand, and many of the descriptions of making Damascus talk about billets that would be very hard to do without a press. I would say keep it small, and take some time to make a spring fuller. When I finally made one it cut the time to draw out a billet in half.

Other than that, give it a go, no better way to learn than by doing.

Have fun, Justin

Jared, I agree with Justin, if you are not using a press or hammer keep your layer count low to start with. My opnion start with about 5 layers if you are going to do it all by hand. You are also right on grinding all the mill scale off the steel to start, the smoother you get the steel to start the easeyer it will be to weld together. I grind all the pieces I stack together down to 320 grit seems like it takes less pressure to get it to weld. when the whole billet looks like the inside of the forge it will be close to welding, you wont have to hit it really hard to weld it, over lap your hammer blows and start by going straight down the center of the billiet then work out one side then the other. this could take more than one heat till you get the feel of it. hope this helps. Landon

Thanks Guys, Soon as I get my steel in the mail I'll give it a go. I'll probably post some video to Facebook or YouTube that way some of you more experienced than me may be able to look and tell me if I need to change anything.

This is part of the booklet I wrote for the pattern welded seax class I taught at NESM.

Methods of Modern Pattern Welding

The part of pattern welding that is always the greatest fear for any new bladesmith is the welding. Welding in this context is actuality rather easy; so long as a few simple conditions are met the weld will take. (warning science stuff ahead!)

First, what is a forge weld? A forge weld is properly called a solid state diffusion bond, which is to say that no part of the metal becomes liquid at any time in the process. In the solid state, metals exist in a form where the nuclei arrange themselves in an orderly grid and the electrons are shared as an "electron sea". This is why metals make good conductors of both heat and electricity. In the case of forge welding, the weld is formed when the two pieces of steel are brought close enough to begin easily passing electrons back and forth, in essence becoming one piece. As part of this process alloying elements may also diffuse across the weld boundary slowly homogenizing the steel. Some elements such as carbon move relatively quickly, while others such as chromium move much more slowly. The differences in alloying elements between the two steels used are what cause the pattern to be visible when etched.

To form a successful weld, three conditions can be thought of as necessary. The first condition that must be met is a perfectly clean pair of surfaces. By this I mean that there can be NO oxides present in the weld zone and no foreign matter to become trapped in the weld. The second condition is an inert atmosphere around the weld. This prevents any oxides from forming during the process, since these would prevent the electrons from easily crossing the boundary. The third condition is proximity. The two surfaces of the weld must be brought into close contact since this encourages the electrons to cross the boundary and a metallic bond to form. Heat is not necessary but can help to create the conditions necessary to make the weld. Higher temperatures mean greater energies, and at higher energies it is easier for the electrons to jump the boundary. Iron oxide actually melts at a lower temperature than iron itself, so higher temperatures can help oxides on the surface to breakdown or flow away. Lastly, higher temperatures mean softer materials, and softer materials make it easier to forge the surfaces into the atomically close contact necessary for the metallic bond to form.

Creating the necessary conditions can be accomplished using more than one method. The classic method is the flux weld. In this method a flux (most often borax) is used to break down the surface oxides at high temperatures (meeting the first condition) then forming a glassy film sealing the surface (creating an inert atmosphere and meeting condition two). The flux is then forced out of the joint when the hammer blow presses the two surfaces together (bringing the two surfaces into close proximity and meeting condition three). The downside of this method is the likelihood of trapping flux in the joint. Even on the very best flux welds, flux can be seen in the joint on a microscopic level. Due to these inclusions, flux welds work best and are strongest when they are drawn out to at least twice the original length. This refines the weld and distributes any possible inclusions over a greater area.

A more modern method is the box weld. In this method the plates to be welded are cleaned of scale and oxides by grinding the surfaces clean. They are then stacked and tacked on the corners with an electric welder. Following this they are soaked in kerosene and a sheet metal box is built around the stack. The box is sealed with some of the kerosene inside and a small pinhole is left open in one end. The box is heated in the forge, burning off the kerosene and creating a reducing atmosphere inside the can. Once heated through, the billet is then compressed to set the welds. In this method the first two conditions are met by the burning off the kerosene. This creates a very reducing atmosphere in which no oxides can form and existing iron oxides are reduced to pure iron. The atmosphere will stay a reducing atmosphere until such time as the billet is cooled. So this meets the first two conditions, and the compressing of the billet to set the weld meets the third. The downside of this method is that it limits the size and shape of the welds along with the work that it takes to form a box for each re-stack. On the other hand this method will form a much more solid weld with NO possibility of anything trapped in the welds. This method is really only viable with access to a hydraulic press as the entirety of the welds must be set at once. This method works especially well with hard to weld alloys like stainless steels and for oddly shaped welds as in mosaics.

A very new method of welding is the oil weld or kero weld. In this method the forge is run up to welding temperature, and adjusted to run rich, creating a reducing atmosphere. The plates to be welded are tightly stacked and tack welded on the corners. The billet is then soaked in oil or kerosene before being heated and soaked at welding temperature for 1-2 minutes after reaching the welding temperature. The billet is then run under a power hammer or hydraulic press to set the welds. This method works under the same chemistry as the box weld except it uses the atmosphere of the forge and the burning oil to create the heavily reducing atmosphere needed to reduce the oxides and clean the surfaces. This method seems to work best if a power hammer or press is available, giving clean, strong welds without the extra work of a box weld. A related method, the so call “bareback” weld, uses the reducing atmosphere in the forge and slightly longer soak times at welding temperature to break down the oxides. This method works surprisingly well and produces exceptionally clean and strong welds. It can lead however to strong decarburization along the weld lines due to the carbon in the steel being removed to bond to the oxygen from the oxides and form CO2. Some testing has also shown minor oxide inclusions at the edges of the billet in both the kero and "bareback" welds, but most smiths consider the small inclusions to be a minimal drawback in comparison to the many advantages of these welding methods.

Whatever method you choose to use should be based first on your available equipment and second on your material choices. For example, I have had less than perfect results welding wrought steels and iron with any of the fluxless methods, possibly due to the silica slag that is inherent to these materials. As with other aspects of knifemaking, reading everything you can on the subject is advised; understanding how others are doing things and how something is working can go a long way to helping diagnose problems when it suddenly stops working.

When welded the class billets should have an average carbon content of about 80 points and should heat treat similarly to 1084. You can compute the total carbon content to a fairly close degree by adding up the total amount of thickness of the billet. Next, add up the amount of thickness of each alloy. Use the thickness numbers to figure out the percentages of each alloy. Use the percentages to find the mean average of the two steels' carbon contents. This is not necessary when using 15N20 and 1084,1075 or 1095 as these mixes in any ratio will end up with a good carbon content.

The Flux Weld in Practice

To begin, prepare the billet to be welded by stacking tightly, clamping and welding the corners to hold it together. Or you can bind the stack tightly together with iron wire. At this point a handle can be welded on, or tongs can be used to hold the billet when welding.

To flux weld, the billet should be heated to a dull red heat, removed from the forge and fluxed. Place it back in the forge and take the billet to a welding heat (a bright yellow almost white heat, about 2300ºF). Remove the billet and use a wire brush to remove the spent flux. Reflux and replace the billet in the forge. Once the billet is back to a welding temperature, set the welds on the anvil with firm blows of the hammer. Begin at one end and overlap your blows setting the welds along the length of the billet. Wire brush the spent flux off and repeat to be sure the welds are solid. The welds can also be set using a hydraulic press rather than a hand or power hammer. With a press it is best if the whole of the weld can be set under the dies at one time. Squeeze down until you see the flux run out the sides. Do not forge the bar on an angle, this will put a great amount of strain on the weld and cause it to sheer, for as long as possible draw the weld out parallel to the weld.

Look for dark spot or lines dividing a hot and cool section. This indicates that a weld didn't take. If they show up, reheat, flux and re-weld that section. The welds can also be set under a power hammer. This is helpful with larger billets, but is unnecessary with the smaller starting billets used in Viking style pattern welding. A note on the hammer used for welding: the size of the billet you are making will to a great extent determine the size of the hammer needed. The larger the billet, the larger the hammer needed. A heavier hammer will transmit more force to the center of the billet than a lighter hammer. For this reason there is an upper size limit on billets that are practical to weld without a power hammer or forging press. If only the core layers are taking, try a lighter hammer as too much of the force could be going to the center of the bar. If only the outer layers are taking, try a larger hammer.

Common Issues with Flux Welds

Trapped flux- To prevent, wire brush and reflux often and do not over-flux the joint. There should be just enough flux on the joint to wet it when heated. Do not soak at temperature too long, and overlap the welds working from the welded section back. To repair, scrape out the trapped flux and re-weld If possible. If not cut out this section or work around it.

Weld sheer- To prevent this work only at a higher temperature and KEEP THE BAR SQAURE TO THE WELDS as long as possible. Repair when possible by re-squaring the bar then fluxing and re-welding.

Sections not welding- To prevent, be sure the bars are clean and fluxed and at a high enough temperature to weld. To repair, wire brush and reflux 2-3times to remove any oxides that might have formed before attempting to re-weld.

For an oil or bare-back weld, set the forge to a high heat and a reducing atmosphere (slightly gas rich). I prefer to clean the steel by grinding beforehand, but this is not strictly necessary. Electric welding the billet together works best as the weld areas need to be held in close proximity when heating. Wiring the billet together is another possible option. Place the billet in the forge and bring it up to a welding heat. Soak it at temperature for 4-5 minute, (more time than is actually needed, just to be sure of a long enough soak.) then set the welds under a power hammer or press. This works best if the whole of the weld is set at once. Use a long set of press dies or go across the wide side of the power hammer dies. Once set, the billet can be drawn out as normal. This type of welding produces from the start a very strong weld. Much less care needs to be taken when drawing. There is a slight tendency not to weld at the very edge of the billet. This is for the most part superficial and easily removed by grinding. If present, it should be removed as the billet is prepared for twisting.

Matthew

Very well done! Thank you.

Well I finally did a forge weld. I know that this post is seventeen months old but we had a new member join the family last December so I haven't had a whole lot of shop time on my hands until recently. It turned out to be wrought iron which made for a tough first time. I have never worked real deal wrought iron before and I was just planning on flattening it out enough to get a guard size piece and maybe a butt cap but when I started hammering on it it jus started mashing and separating. Out of necessity I folded it back on itself and attempted to weld it. Having no luck with the first try I flattened it out good and made sure it was all touching together. I fluxed it with some 20 mule team borax which is all I had. It seemed like I had to get the forge hotter than hell fire to get the iron to even barely stick. I eventually folded it back on itself 5 times and got about a 1/2x1" by 5" piece out of the bar I was using. There were a couple of times when I was folding it back on itself that it just broke off and I had to tack it back together with the wire welder before completing the hammer work.

I guess what I would like to know is if this is normal for wrought iron or did I get some cruddy material.

P.S. I hope welding good steel 15n20 and 1084 is easier than this was. Mainly around the edges it just seemed to want to fall apart.

The short answer, yes. I have only forge welded with WI once when making a tomahawk head with high carbon core. The WI will move much more easily than the high carbon, so that was a little interesting for me trying to shape the blade on the head... I've not welded WI to WI, but everything I've heard is that in order to get good results, you're going to want the forge all kinds of hot. Hotter than you normally would have for a typical 1080/15n20 combo. The other thing is, WI comes in all kinds of "quality" levels. Some has far more inclusions than other. I understand that some of the more clean WI was used in chain, like big anchor chains. But, when you have some of the less pure stuff with some nice inclusions, it can lend to some more "active" and interesting looking stuff when you etch it. Some of those other bits in your WI probably made for some of the difficulty with it coming apart while forging it. Hopefully some others with more experience will chime in here. Karl has made some super cool stuff with WI and he's done a fair amount of forging it. I've seen some where he has twisted it and then etches it, showing some really cool stuff when finished. I bet the bar you now have is pretty neat looking when finished out. Congrats on working through the difficulty and getting metal to stick together. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' />

Jeremy

Congratulations Jared! Forge welding is where the rubber meets the road, so to speak. Glad you are getting in there and doing it. When you get a chance, please share a photo of the finished work. Don't be shy, be proud. This was a major achievement.