Welcome everyone to another exploration of crucible steel.
In this episode, I will show you how to turn old wagon tires into a powerful crucible steel
utility knife.
If you have not watched my previous episodes on Wootz steel, you might watch to catch up
as I will be covering it only a very high level.
For making crucible or Wootz steel, we need to start with a lot of iron first.
I cut up the wagon tires, and am now forging them into long thin strips.
Even that can look very pretty.
Once the wrought iron has been forged, it needs to be cleaned up.
Otherwise, the scale and rust is going to cause problematic chemical processes in the
crucible.
The one step I have changed in my usual process is to coat both of the outside and inside
of the crucible.
I am hoping that this might protect the inside from the furnace atmosphere.
While it might me tempting to run the furnace in the shop, it generates a tremendous amount
of heat and we have seen ceiling temperatures of up to 200 Fahrenheit.
For those of you living in metric countries, that's almost 100 Celsius.
Once the furnace has heated up, we insert the crucible and now bring the inside temperature
up to 3000 Fahrenheit.
That's about 1650 Celsius.
In previous experiments, I was worried that too much oxygen might be dissolved into the
steel.
Since we are not killing the ingot with aluminum, we instead are trying to conduct this run
as quickly as possible.
We take frequent readings with an infrared thermometer - hence the ladder you see in
the background - and then ramp down the temperature and let the crucible cool down inside of the
furnace.
Opening the crucible is like unwrapping a christmas present.
I hope we will be positively surprised.
Under Tony's expert ministrations the ingot is about to be revealed.
Unfortunately, we see a lot of air pockets which indicates that gaseous reactions in
the crucible had not finished by the time we reduced the temperatures.
Ordinarily, I would just toss the ingot into the scrap pile but we decided we would try
to forge the steel anyway.
As you may remember in previous experiments the ultra-high-carbon crucible steel would
not forge easily.
Let's see how this ingot will fare.
The ingot is oddly shaped and my first goal is to consolidate the ingot into a bar that
can then be forged into a large knife.
Because of all the holes, I am forging the ingot quite hot and apply flux so that perhaps
I can forge-weld the steel and make some of the holes disappear.
This strategy appears to be working well.
I often receive comments that my work is not authenic enough because I use modern tools.
Nothing I show here could not be accomplished without a power hammer or a welder but it
would take more time and more man power.
Both of which I do not have.
So there.
One way of testing carbon content is to analyze the sparks.
The more carbon the more stars will form.
Let's look at this in slow motion.
This does not look ultra-high carbon to me.
I guess it's probably close to .6% - so still hardenable.
The first step to turn the crucible steel bar into a knife is to isolate material for
the tang.
Once the tang has been established, I will forge over the tip.
Let's do that in slow motion again.
While completely irrelevant, we can see the 60 Hz flicker of the lights.
The fullering dies on the power hammer are also a good way to elongate the shape of the
knife until I am happy with it's overall proportions.
Here is a somewhat ill-fate attempt at moving the tang transition to the blade.
It did move but only a little.
Now, it's time to forge in the bevels.
The beveling jig on the power hammer makes this easy but the fine tuning still happens
by hand.
In blacksmithing, a large amount of time is devoted to making tools.
Sometimes they need to be adjusted as you see here.
Forging with water on the anvil helps with removing scale.
The idea is that the water gets trapped, vaporized and blows of the scale in the process.
Video makes it difficult to judge the temperature of the steel, but I am forging too cold here.
Not something you want to repeat.
However, the slight adjustments on the back can be done cold.
At this point, I am normalizing the knife to refine it's grain structure.
That's basically heating it up to critical temperature and then letting it cool down
in the air.
As I have said before about 10% of the time is spent forging and a lot more time goes
into grinding.
A push stick helps with quicker action.
Just before heat treating, I like to remove vertical grinder marks as they may become
troublesome in the quench.
I am quenching in Parks #50 which is a high-speed oil.
Let's enjoy this in slow motion, too.
The blade looks nice and did not warp.
Now, more grinding is called for to reduce the thickness of the edge.
Since the blade is hardened now, I need to control the temperature.
Patience is a virtue.
One that I do not always possess.
So, let's take a look at the pattern.
The etch in ferric-chloride shows nice carbide patterns.
To increase the toughness of the blade, I am tempering it at 500 Fahrenheit for an hour.
That's about 260 Celsius.
Now that the blade is mostly done.
We need to make a bolster and a wooden hilt.
The aesthetic that I am going for is simple and utilitarian.
Since Tony is visting from Chicago and our time is limited, we need to do some of the
finishing work in the garage with less sophisticated tools.
We drill some guide holes into the copper and then chisel open the slot for the tang.
Here you see me refine it with a file before fitting it on the tang.
While the fit is reasonably close, some filing is still required to seat the blade properly.
If you pay close attention, you will see that the edge is not quite straight at the tang
transition.
That will get removed to make the lines perfect.
I picked up some split hardwood at a lumber liquidation sale and Tony is now cutting a
piece with a knot to make for an interesting grain pattern.
As usual, I prefer to burn the tang in, so now I am drawing guide lines for the drill.
The drill bit on the drill press is too short.
This is because the handle is quite long.
I prefer the handle to be 1/3 of the length of the total knife.
That makes for an aesthetic I enjoy.
When drilling by hand with a long drill bit, it's important to get the right alignment,
since I am following the previous holes that's pretty easy in this case.
I also marked the drill bit to know when I need to stop.
Once the tang is hot enough, it burns through the wood quite easily.
Since heat travels through metal slowly, there is no danger in affecting the temper of the
blade.
The resulting imagery can be quite appealing.
The remaining steps are pretty straight forward.
The big block of wood now needs to be shaped so it feels comfortable in the hands.
To look right, it also needs to taper appropriately.
While the wood looks very interesting, shaping it unfortunately revealed some flaws that
cannot be completely removed.
As you will see in the final result.
Creating even a simple knife can take a lot of time.
While I did not keep track for this experiments.
I suspect that just creating the steel and forging it took about 12 hours and perhaps
another 15 hours until it is completely finished.
Since the blade has a good frition fit, I will be grinding bolster and wood together.
I protect the blade with a double layer of masking tape.
Grinding wood creates a lot of dust.
To make that less of a problem, I set up a little fan to at least blow the dust away
from me.
While the grinder removes a lot of wood fast, the final clean up still needs to happen by
hand with 220 grit sand paper.
A side effect from burning in the tang was a lot of oily smoke that got deposited on
the blade.
600 grit wet or dry sand paper comes here to the rescue.
I also find polishing somewhat soothing.
To protect the wood, I am applying tru oil gunstock finish.
This will bring out the pattern and create a clear protective coat.
It requires about 5 layers and you will see a couple of iterations in this video.
Before I can glue everything together the copper bolster needs to be polished.
First on the belt sander and then by hand.
Instead of epoxy, I should really use my stash of cuttler's resin.
It is incredibly messy though and for the time being, two-component epoxy works just
fine.
I am using a slow-setting epoxy here, so handling time is about 30 minutes and it takes over
8 hours to cure.
At this point, everything is pretty much a friction fit and I do not need to use a lot
of epoxy.
However, the expectation is that some of it will be pressed out and then needs to be cleaned
up.
To clean up epoxy, I use degenerated alcohol.
There are lots of ways to safely clamp a knife for curing, I usually prefer the cork of a
wine bottle so that I can safely rest the tip against the clamp.
It's time to wait for the epoxy to set.
This might mean reading a book with a tasty coffee or perhaps a single-malt scotch.
I sharpen against the slack belt.
This makes for a convex cutting edge that can take some abuse.
I had planned to cut through a broken tree branch as a cutting exercise but had not expected
all the rain in California.
While a blessing for us, I did not want to film while it was raining.
So, you'll just see a couple simple cuts.
Here is the final result.
Old wagon tires finding a new use in a crucible steel knife.
The grain pattern is very subtle and I did my best to show it to you on video.
I hope you enjoyed this video.
Creating these videos takes a lot of time and expensive equipment.
Filming, editing and grading this video took nearly 40 hours.
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In the next video, you will see me recreate an historical viking-age wolf's tooth spear.
That's it for now, see you next time.