Below is the first post in a thread on B-ARFCOM started by user, Kuraki. It’s pretty nifty and you can read more and follow the thread from the link at bottom.
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.
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 2×72 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.
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