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Posted: 11/5/2020 2:17:38 PM EDT
Specifically, a mosaic pattern called basket weave. The end result should look just how it sounds, like a 90s Safariland holster. First, when I say "damascus" I mean modern damascus, which is technically pattern welded steel. Colloquially it's called damascus, all "ackchyuallys" aside.
The steel alloys I'm going to use are Crucible Cru Forge V and Uddeholm 15N20. Some thought goes into choosing alloys. First is whether or not they will have a contrast that will allow the pattern to show up when etched in acid. Second, since we're making knives out of this eventually, is whether the alloys have a similar response to heat treating since you can't harden them individually once combined. Cru V was developed by Crucible to support the burgeoning custom knife market in the mid 2000s before their bankruptcy, and is no longer made. It's fantastic in damascus because it etches very dark black, and the vanadium content helps prevent grain growth during the many heating cycles required to make pattern welded steel. 15N20 has a nickel content of 2% and so it resists etching, and therefore forms the "white" layer in damascus. Both respond very well to a heat treat of 1500F, oil quench and 400F temper. Lets start on my white board. The first step is to make a stack of alternating layers that will be forge welded together. Attached File To prep for this, I start by cutting the steel to length and then surface grinding it. Surface grinding it removes the mill scale and gives me nice flat surfaces that are in good contact with each other. I converted my surface grinder to run 2x72 belts and they run at roughly 6,000 surface feet per minute. It will really rip steel quickly compared to how surface grinders are typically used. It's not uncommon for me to take .030" depth of cut per pass with a .100" step over. Which would be insane with a regular grinding wheel. Now, I need to hold these together to forge weld them. To do that I'll MIG weld them with fairly low heat, I don't want a lot of penetration because I don't want the mild steel wire to exist in the final product. This cheap little vise works really great for getting everything tight face to face. After MIG welding the billet together, I soak them in kerosene. This is a relatively new method for doing initial billet welds. Traditionally the dry, unfluxed billet would be put into a pre-heated forge and allowed to come up to a red heat before flux was applied to it. Then, (hopefully) the flux would penetrate between the layers and stop the oxidation of the steel before it starts, or clean out what had already started. Soaking in kerosene seems to protect the steel from forming any scale in that initial heat cycle, I'm guessing for 2 reasons, one is that it burns off in the forge consuming any latent oxygen in the forge environment. 2, being about the cleanest hydro carbon you can get your hands on, burning off likely leaves a film of almost pure carbon on the steel that doesn't interfere with the weld and likely protects the surfaces from oxidation for a short period of time. So the benefit is a better chance at a successful weld, and a cleaner weld with no flux trapped deep between the layers. Then, with safety in mind, I weld a piece of rebar on to the stack for a handle. I use a vertical forge, so welding a handle on is a necessity as there's no shelf inside for the billet to sit on. Vertical forges are superior for this kind of work as they allow the billet to heat more evenly, but they suck for forging to shape where tongs are more useful than welded handles compared to a horizontal forge with a shelf/table/floor inside. Then it's into the forge, which has been pre-heated to about 2200F. The dragon's breath coming out of the opening is a good sign. That means there's not enough oxygen in the forge for all the available fuel to be consumed inside. Oxygen is not our friend when forge welding. Here's forge startup and preheat (sped up, it takes about 20 minutes after lighting, and not this first billet going in there). This forge has a forced air blower with LP injected into the air stream at ~5 psi. Failed To Load Title More to come. |
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Very cool. Metallurgy has always been an interest of mine. Keep posting as you progress!
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I learned something new. Now I can yell at the Smiths on FIF for not soaking their billets in kerosene first.
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Here's a video of the first round in the forging press. There's two methods of mechanical forging commonly used, and if you've seen Forged in Fire you've seen both. Power hammers and hydraulic presses. They do similar things to the steel, but have their own little idiosyncrasies that make them both better at certain tasks and worse at others. I have a press because it was easy for me to build one without any real engineering issues. It's essentially an H-Frame press with the same hydraulic circuit as a log splitter. Mine is 5hp, and develops about 20 tons at max pressure. There is an important correlation between speed and pressure when it comes to presses and forging, both are important and if you understand hydraulics you understand that they're inversely related. Speed is important because when the billet is in contact with the dies, the dies are drawing away heat. This is what makes the mechanics of forging in a press versus a hammer so different. A hammer strikes - very little heat is lost, in fact, with the right power hammer, heat can actually be developed while hammering. That violent strike isn't great for the initial weld, as deforming the steel layers before they are fully welded has negative consequences to the likelihood of a good weld. So presses are generally better for that.
My press is loud, so fair warning on the volume of the video. You'll notice the very first hits are very light. I'm only trying to get all of the layers in contact with each other, without deforming the billet for the first couple heats. Subsequent heats I'll start actively reducing the size. Failed To Load Title |
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Great thread OP. I have no interest in getting started myself, but I love watching the process of creating something beautiful from random chunks of steel.
Damascus is awesome. |
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Here the billet is welded completely and I'm just drawing it out. I'm primarily working in one direction, so when I flip it on it's side, it's only because I'm trying to limit deformation and growth in the width of the billet, so I'm just hitting it to keep things true. I want to end up with a square piece of bar that ends up about 34" long. If you do watch through you'll see at one point I start cocking the billet in the press, this is to try and correct for the fact that my press will make rhombi shapes instead of square shapes. It's a little too loose in one axis and just gets worse over time. Eventually I'll need to build a new press, this time with adjustable gibs so that the parallelism of the top and bottom dies can be adjusted for wear.
Lots of brushing and fluxing to try and keep the scale out of the billet. You can see it fall away sometimes as the billet is compressed when it's gotten away from me. I should take a picture of my scale brush. It's something else. It's flat bar instead of wire and could be used as a weapon. Failed To Load Title |
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Now we're getting to the end of this step. You'll see I've got 2 bars in the bottom die now, they're acting as stops so that I can hit a specific size. I've got a slightly under 1" square bar now. It's a little hard to keep something this long completely straight, sometimes between heats I'll be hammering the bar on the anvil just because it's easier than straightening in the press. But it doesn't need to be perfect, as this bar will be cut into short sections that are relatively straight for their length.
Failed To Load Title That brings us to the next step. I'm going to cut this bar up into sections, and grind the ends and etch them so I can combine them into 4 part squares with alternating directions of the layers. Attached File This is the beginning of the pattern. I'll do this with 4 different billets. Because the weld seams are now cutting across 2 axis of the billet, I'll have to set the initial welds differently than the first stack up. To keep from shearing them apart, I'll set the welds in V block dies on a diagonal. Kerosene again. See if you can spot my mistake! Failed To Load Title When I grind the ends and etch I now have something like this: Fuck wait a minute that ain't right When I was tacking these together, 2 pieces fell out of my vise and I must have put them back in without looking very closely. Luckily I have 4 bars extra so I can remake that one. So this picture is just representative, just imagine the fucked up bar being replaced with one made correctly. And after welding in the V blocks and drawing it out, I've got 4 more bars that look like this: |
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are those the goat/sheep skin gloves. i forget which, but they were my favorite for regular use. Soft yet works well.
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Subbed! A few questions as a Forged in fire fan:
Did you ever forge shit by hand or is that a fools errand? Are you the chick in the avatar or the troll looking thing with the cigar? How much to spend a week sleeping on the floor as your apprentice to learn how to do this? |
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That is so cool. Blacksmithing is an awesome trade and the process for Damascus is bitchin.
You should make some Imperial stamped Beskar ingots from Mandalorian. They would sell like hotcakes |
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Quoted: are those the goat/sheep skin gloves. i forget which, but they were my favorite for regular use. Soft yet works well. View Quote Deer and goat are the best. Deer is less durable than goat, but both can get wet and dry out without hardening. Cow leather is great for durability but that's about it. |
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Quoted: Subbed! A few questions as a Forged in fire fan: Did you ever forge shit by hand or is that a fools errand? Are you the chick in the avatar or the troll looking thing with the cigar? How much to spend a week sleeping on the floor as your apprentice to learn how to do this? View Quote I'm the troll with the smoke, the chick is married to the troll. A handle of Korbel brandy and a pizza or two. C'mon up. |
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Wow, this is a great distraction thread
Now, back to the election |
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So with CFV and 15n20 having similar heat treat profiles what hardness are you looking at?
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Thats badass . Ive always thought the wirerope/steel cable blades were awesome as shit as well .
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Quoted: true.dat Mine is all dirty...not god for anything but decorative stuff. View Quote View All Quotes View All Quotes |
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