Tamahagane tanto wip

[Francis Gastellu]

Hi everyone,

 

This will be my first attempt at producing a tamahagane blade, so be warned, this may or may not go anywhere  I'll be aiming for a modest size tanto to limit my losses in case I completely mess up, since I might just end up making expensive wrought iron instead.

 

The bloom was smelted by another smith with ore from the Rio Tinto river in southern Spain.

 

 

Spark testing shows consistent high carbon throughout (1.2-1.5% according to Pierluigi):

 

 

 

I am more or less following the traditional process, except for a few things that are currently outside of my control. For instance, I am using a propane forge instead of the traditional charcoal forge, which I have been warned multiple times could cause me to lose all of the carbon in the very first weld. Seeing that Walter Sorrells forges tamahagane with propane (or so it appears in his videos), I figure this is at least not hopeless. I'll be running fuel rich, obviously, and will use the traditional coating of straw ashes and clay to attempt to mitigate the loss (which I believe Walter does not actually use)

 

 

The bundle starts at about 1.6kg of material.

 

I knew that keeping everything together was going to be a challenge and I was not disappointed. Ultimately I lost part of a corner of my stack, and had to square up the billet somewhat sideways (making for a really inconvenient handle alignment)

 

Folding hot is entirely new to me, I would normally let everything cool down, cut, surface grind, tack weld, then go back to the forge for the next weld. I figured how hard can it be? I then eyeballed the worst 50/50 you've ever seen and hot cut the billet literally at the 2/3 mark... so I did another cut at 1/3 on the other side and folded into thirds .

 

I fought with that a while before doing fold #2, this time length-wise. At this point, the position of the handle was just not conducive to squaring the billet properly so I had to stop until I could clean things up and re-weld it.

 

I also took the opportunity to make a quick and (VERY) dirty billet divider (oh my, look at those rivets).

 

 

I did another 2 folds and had to pause again, this is where I'm at after fold 4. 

 

According to The Craft of The Japanese Sword, the first welding/consolidation operation should lose about 0.3% of carbon content, while subsequent welds should lose an order of magnitude less, at 0.03% per fold. I was therefore curious to spark test what I have so far.

 

 

Still looks like quite high carbon so far. There should be a total of 8 or 9 folds left to do for an additional 0.25% loss or so. Cleaning up a bit to reattach the handle shows a cleaner surface than I expected at this stage.

 

 

So I guess, onward and upward!

Edited March 31, 2022 by Francis Gastellu

[Emiliano Carrillo]

looking good! I tend to start with tamahagane or oroshigane at about the same level of carbon and fold to 10-14 folds depending on what I am making. I also do all of my work in propane though I will soon have a charcoal forge made up for hardening work. What are you using for your forging? Is it all by hand or do you have a press or power hammer? I use a power hammer and try to do all of my folding as quickly as possible. I start with ~5lbs of material and usually end up with about 30-45% of my starting weight when finished folding after a few hours. 

 

My most recent works have been about 5.5-6 hrs of folding to get to a usable bar of material. I like to work as quickly as possible in order to mitigate carbon loss due to using propane as my fuel source. I don't use clay or straw ash to mitigate carbon loss, but usually end up with enough carbon to make good hamon and harden to 62-64 RC out of the water. Anyway, looking forward to seeing your results! I don't weigh everything as carefully as I did when I first started anymore, for a while I was measuring loss after each fold in order to understand where the inefficiencies of my process were, but now I just make sure I know much much material I am starting with and generally can guess how much I will have when I am finished. 

[Francis Gastellu]

2 hours ago, Emiliano Carrillo said:

looking good! I tend to start with tamahagane or oroshigane at about the same level of carbon and fold to 10-14 folds depending on what I am making. I also do all of my work in propane though I will soon have a charcoal forge made up for hardening work. What are you using for your forging? Is it all by hand or do you have a press or power hammer? I use a power hammer and try to do all of my folding as quickly as possible. I start with ~5lbs of material and usually end up with about 30-45% of my starting weight when finished folding after a few hours. 

 

My most recent works have been about 5.5-6 hrs of folding to get to a usable bar of material. I like to work as quickly as possible in order to mitigate carbon loss due to using propane as my fuel source. I don't use clay or straw ash to mitigate carbon loss, but usually end up with enough carbon to make good hamon and harden to 62-64 RC out of the water. Anyway, looking forward to seeing your results! I don't weigh everything as carefully as I did when I first started anymore, for a while I was measuring loss after each fold in order to understand where the inefficiencies of my process were, but now I just make sure I know much much material I am starting with and generally can guess how much I will have when I am finished. 

 

Thank you Emiliano, those are good ballparks to keep in mind while I figure my own process. So far I fear I've been working fairly slow, and this may bite me in the end. It took me over two hours starting from loose stack to after the second fold was welded. Last two welds have been faster, billet is starting to behave. I have a small power hammer (anyang 33lbs) that took over the heavy lifting of drawing once the billet was solid enough.

 

One thing I didn't mention is that although I used clay/ashes for consolidating the bundle, I used borax during folding. The clay was making a mess and ultimately I'm a lot more familiar with borax. Without seeing it dancing on the hot steel, I wouldn't be sure when to set a weld.

 

The drawback of borax is that like many, I have an impulse to use more of it to attempt to compensate for my lack of skills. My forge has taken a beating and needs a new floor. 

 

Edited January 4, 2022 by Francis Gastellu

[Alan Longmire]

Looks good so far!  

[Joshua States]

The steel is looking quite good. I ike your little dividers too. I am far too lazy to make anything like that.  I just take a ruler and a soap stone and mark the side of my anvil in 1/2" increments. These are worn off now, but I just touch them up when I am doing billets.

[Francis Gastellu]

5 hours ago, Joshua States said:

The steel is looking quite good. I ike your little dividers too. I am far too lazy to make anything like that.  I just take a ruler and a soap stone and mark the side of my anvil in 1/2" increments. These are worn off now, but I just touch them up when I am doing billets.

 

That works, and definitely a simpler solution 

[Joshua States]

My favorite personal quote/motto:
I am fundamentally a lazy man. The most effort I will spend on any endeavor is figuring out the easiest way to do it.

[Francis Gastellu]

I completed the foundation forging:

 

 

This looks suspiciously clean, and since this is the first time I'm doing this, I figure I'd etch so I'd get a better idea of what I've actually been doing:

 

 

There are definitely questionable spots here. Good thing there's more folding to do, that should give me plenty of opportunities to add more of them.

[Jan Ysselstein]

Francis, thank you for posting your project…..will it still spark as the one above? You have posted the cleanest intact hands I have ever seen here….you must wash the dishes every night.

 

 

[Francis Gastellu]

11 hours ago, Jan Ysselstein said:

Francis, thank you for posting your project…..will it still spark as the one above?

 

It does but the carbon has definitely gone down.

 

 

Activity looks similar to 1095 and W2, I'm guessing/hoping that's about where I'm at.

 

12 hours ago, Jan Ysselstein said:

You have posted the cleanest intact hands I have ever seen here….you must wash the dishes every night.

 

My girlfriend wishes I did!  Intact yes, only a few stitches. Also this heavy duty soap is amazing. No, really.

[Jan Ysselstein]

Thank you for the second spark test...looks good . I don't know if you make the high carbon iron from magnetite sand or by carbonizing iron. Magnetic sand is available to us here in California and I have used it..have not  made a lot of high carbon material but lots of iron and cast iron. If you are using the magnetic sand and getting high carbon iron we may want to share our notes.

 

Oooops I just read the source of the material at the top of the post.

 

Edited January 17, 2022 by Jan Ysselstein

[Francis Gastellu]

47 minutes ago, Jan Ysselstein said:

Thank you for the second spark test...looks good . I don't know if you make the high carbon iron from magnetite sand or by carbonizing iron. Magnetic sand is available to us here in California and I have used it..have not  made a lot of high carbon material but lots of iron and cast iron. If you are using the magnetic sand and getting high carbon iron we may want to share our notes.

 

Oooops I just read the source of the material at the top of the post.

 

 

As you saw, this was smelted by Pierluigi Ponzio from magnetite sand. Unfortunately doing my own smelt is just not an option where I'm located, but it's one of those things I know I'm going to have to do at some point. As it turns out, the place I'm from and where I want to retire in a few years isn't too far away from Pierluigi... maybe he'd be willing to let me steal his secrets 

 

[Francis Gastellu]

I did only two more folds before kobuse. My thinking was that on one hand I've been quite slow in my folding overall, and I suspect my rate of carbon loss is quite a bit higher than Yoshindo's, and on the other hand the steel has felt like a solid billet since fold #4. My understanding is that I'll lose some homogeneity in the carbon content by stopping at #8, but I don't dare continue to put this billet through any more high heats. Hopefully I can get away with it on this small blade.

 

(I made this bottom tool for canisters. I've never forged a canister yet  but with a 1" round bar as top tool, it works great for kobuse! )

 

 

 

 

A couple things for me to remember next time:

 

1) I didn't take the arc and thickness of the fold into account and my core stuck out a lot. I could have forged the core down to match but everything was ready at that point, so I just went for it anyway and ultimately ground the excess.

2) I should have pinched the bun a lot closer to the end of the billet, I lost quite a bit of material with this mistake.

 

If you're wondering where the shingane (core steel) comes from, it doesn't: I've used a piece of wrought iron (quite clean, from anchor chain) instead of making mild steel from bloom. Although the material I got from Pierluigi wasn't nearly as expensive as if I had gotten it from Japan, it's not exactly cheap either and pretty much all of it is HC, so I'd prefer to keep it for edge steel. Oh yeah, it'll also save me a lot of folding, not gonna deny.

 

Hopefully the rest is straightforward, but that's assuming my welds are good. We'll see  

 

Edited January 23, 2022 by Francis Gastellu

[Joshua States]

This is a fantastic WIP thread. Thanks for posting it.

[Francis Gastellu]

9 hours ago, Joshua States said:

This is a fantastic WIP thread. Thanks for posting it.

 

My pleasure, and thank you. I hope y'all don't mind that I'm taking my sweet time

 

Today my plan was simply to draw out the billet into "final" bar stock, but while heating it up I could see shadows that made it clear my kobuse weld had cavities. I spent another hour in and out of forge welding temp to try to fix that. I got really concerned with a blister I just couldn't close up. I've dealt with trapped flux before by punching through an outer layer with a hammer eye punch, but I didn't want to cause a blemish on the hada (final blade pattern). I resorted to something that might be crazy at this stage: water quenching the billet to cause some cracking on purpose, so that the flux could find its way out.

 

I couldn't see an actual crack, but it seems like it worked because after bringing the billet back to welding temp, i was able to close the blister immediately. I did 4 welding heats before drawing out the final bar stock. The billet seemed to cool down uniformly so I think I'm in the clear. *fingerscrossed*

 

 

We're at 28mm x 7.5mm x 220mm (1.1" x 0.3" x 8.7"). If my math is correct, I should be able to get a ~24cm edge (9.5") for a full blade length of ~33cm (13").

 

 

 

And finally, we're still sparking carbon, yay.

 

 

 

 

Edited January 24, 2022 by Francis Gastellu

[Francis Gastellu]

Oh boy, the pressure of the pin is real. Thanks Alan  

[Alan Longmire]

No pressure. 

[Francis Gastellu]

Some failures hurt more than others, this one hurts not just because of all the work in the piece, but because it was entirely preventable, I think.

 

Today I went ahead and turned the bar into a sunboe and beveled the blade.

 

 

 

Everything was going well, steel looked really good and I only had some straightening and some planishing left to do, and then I think I just got complacent and simply forged too cold.

 

 

Of all the things that could have gotten me on this, forging too cold really hurts.

 

I've been able to grind a lot of those cracks out, but not all, and at this point I'm convinced I'm going to reach the core before they're all gone.

 

 

The edge isn't an issue, I left that plenty thick, but I always forge my spines pretty close to finish, and that doesn't leave room for the mess I've made.

 

Time to learn my lesson and start over.

 

I'll still continue the profiling on this one until the cracks are gone just in case I'm that lucky, but I'm not counting on it.

 

Oh well. 

 

 

[Joshua States]

These are the things that make me think of crazy stuff like:

What would happen if I encased this in a can surrounded by powered steel and welded it together?

 

[Francis Gastellu]

7 hours ago, Joshua States said:

These are the things that make me think of crazy stuff like:

What would happen if I encased this in a can surrounded by powered steel and welded it together?

 

 

I like the way you think

 

Well, after an hour of scraping, I'd say there's a non-zero chance I might be able to make a (much) smaller blade than I originally intended. I mean, probably not (and if I do,  there's still a good chance it'll snap when it's quenched) but maybe... just maybe. I'll know more in a few days. 

Edited February 1, 2022 by Francis Gastellu

[Francis Gastellu]

I have to confess, I didn't show the half of it, I was both gutted and embarrassed. I still am, but time has passed, so here goes:

 

 

 

 

 

...

 

And yet somehow, this buffed out.

 

 

This is quite a bit thinner and narrower than I had intended but that's not necessarily a bad thing.

 

 

 

So obviously this blade is highly questionable at this point, and though all (?) the cracks are gone, I can still see some of their "shadows" in the etch. They might go away in the final grind, but that's assuming there will be a final grind.

 

I know what I'm going to do but I thought it might be interesting to do a poll about what people think

 

a) Do a Parks 50 quench, to give the blade the most chance to survive

b) Do a water-to-oil quench, to minimize stress during the convection phase yet still get good contrast in the hamon

c) Do an interrupted water quench. If it can survive that, it'll survive anything.

d) Don't bother, the steel is garbage at this point anyway.

 

Also feel free to predict the result  

 

 

Now obviously I etched this, I mean c'mon, I always etch.

 

 

 

I am a bit concerned about the hamachi:

 

 

It's not a crack, but it's one of those dark layers that I suspect might be crud I didn't get out of the billet, I'm not actually sure. It doesn't show up at all without etching, which is promising.

 

 

And for anybody else than me who also likes gratuitously etched steel, here's the cut-off tip of the sunobe, from before I started shaping/beveling.

 

 

 

[Alan Longmire]

I suspect you will save this one yet!

[Charles dP]

Don’t know enough to be able to recommend between options a-c, I just don’t see any point in d. What have you got to lose?

[Doug Lester]

Is doing a short brine quench to get the steel past the nose of the cooling curve and then letting it air cool to pass from Ms to Mf to avoid the stress from cooling an option?  Just thinking out loud.

 

Doug

[Francis Gastellu]

On 2/2/2022 at 5:34 PM, Doug Lester said:

Is doing a short brine quench to get the steel past the nose of the cooling curve and then letting it air cool to pass from Ms to Mf to avoid the stress from cooling an option?  Just thinking out loud.

 

Doug

 

Ah yes, thank you. I'm not as familiar with brine, but what you suggest sounds like a more extreme version of what water to oil tries to do? Interesting

 

Well, I'm already fighting second thoughts about _that_ plan, so safe to say I'll pass on the brine