Can this tsuba have been made by fusing two iron plates?

[Iaido dude]

This later style Christian tsuba (still has the rays of light rather than clock gear motif) currently on Jauce surprised me when I looked at the images because the half that includes the kogai hitsu-ana has a definitive split such that the tsuba appears to have been made by fusing two separate plates. This is not evident on the other side. We often speak of the fusion of 3 plates or a "pastry puff" appearance of the sukashi walls in Akasaka tsuba. This tsuba has a square rim and hitsu-ana that suggest more of an Owari style appearance.

 

Has anyone seen anything like this?

 

https://www.jauce.com/auction/c1185482684

 

 

[GRC]

A lot of tsuba were folded and/or stacked... the usual mantra for "ko-Akasaka" type tsuba (not that this is one of those) is that there are three layers... but if you look at enough of them, then it gets pretty obvious that there are four layers.

I can see that in some areas on this tsuba, the "top half" plate has a seam that shows that it is also made of two thinner plates... assume the same for the bottom half... and voila, four layers.

Interestingly enough, when you see separation of the layers in other neglected tsuba (like some of the "ko-Akasaka"), the two middle layers tend to stay stuck together, which is probably why the original idea of a three layered tsuba was proposed (but is not correct).

 

My best guess is that the two middle layers of this one were not well forge-welded when it was made, and maybe some moisture seeped in over time, followed by some repetitive freeze thaw cycles over the years in an unheated storage area, which then expanded the frozen water and pushed the plates apart (like road cracks expanding over the winter).  

[GRC]

[Kantaro]

Interesting Steve and Glen, and new for me.

[GRC]

you can also see the four layers on the mimi at the bottom of the second picture that Steve posted.

[goo]

Looks like the iron didn't fuse during the forging process.   Slag or scale got trapped and over time separated the layers.

[Iaido dude]

Very interesting, Glen. This one may prove to be a good reference piece. However, it’s not intuitive to me why a tsubako would opt to forge-weld 4 thin plates together. The total thickness is 4 mm. 

[MauroP]

4 hours ago, Iaido dude said:

However, it’s not intuitive to me why a tsubako would opt to forge-weld 4 thin plates together.

The tsubako didn't weld together separate plates, simply failed to melt together the last folding of the plate (possibly since the temperature of the plate was too low at that point of making). See here another example:

 

[ROKUJURO]

It is as Mauro explained; the cause is too low temperature when fire-welding. Using raw TAMAHAGANE, it has to be folded and fire-welded to achieve a malleable, ductile basic material. This is not different from forging sword-blades.

Rust has a larger volume than iron, so when moisture can enter the finest fissures or gaps, the corrosion build-up will infallibly widen them.

Glen, it has nothing to do with frost; this is what occurs with rocks in nature. 

Subjects like these will be addressed in my TSUBA FORGING SEMINAR July 26/27.

[Iaido dude]

That makes perfect sense now. Thanks, Mauro and Jean. 

[GRC]

38 minutes ago, ROKUJURO said:

Rust has a larger volume than iron, so when moisture can enter the finest fissures or gaps, the corrosion build-up will infallibly widen them.

Good to know Jean. I never would have imagined creeping rust to create such a huge gap between layers. That's pretty amazing actually.

 

Oh and what is this tsuba forging seminar you mentioned? Are you presenting it virtually or in person or both? 

[Steve Waszak]

Interesting discussion.  Over the years, I have seen many tsuba with some degree of separation of folds, usually manifesting especially in the walls of the nakago-ana.  I've seen it so much, in fact, that it seems to be a fairly ordinary occurrence, perhaps especially with older works (pre-Edo).   In the pieces I've seen, though, the separating of the folds is frequently limited to a small area, such as one wall of the nagako-ana, and doesn't extend throughout the plate very far.  Stephen's example here is one of the more extreme cases I think I've seen.  

[ROKUJURO]

7 hours ago, GRC said:

......Oh and what is this tsuba forging seminar you mentioned? Are you presenting it virtually or in person or both? 

Glen,

I announced it in February. No 3 D-printer involved, you will have to hold a hammer:
 

 

[JohnTo]

I bought a rusty plate tsuba with a Chinese scene as part of a job lot and decided to experiment removing the rust with Renaissance Metal De-corroder, as it was junk.  I think I posted the results before.  The interesting thing was that the De-corroder removed the rust without attacking the iron and revealed the layered structure, especially in the nakago and hitsu ana.  There were about 10 layers, indicating that the iron had been folded about 3 or for times.  There was also an area of about 1 cm square on the ji, just to the right and below the nakago ana where a layer of iron, about the thickness of a piece of aluminium foil had lifted off.

Steve's cracks look like poor welding, but don't forget to be aware of lines around the middle of cheap cast iron tsuba.  

 

Best regards, John

[ROKUJURO]

John,

a good portion of the anti-rust product might be phosphoric acid, so it definitely takes some material off the TSUBA surface. Not recommended at all on good TSUBA!

The layered construction is nicely displayed, though. It would be normal for traditionally forged iron TSUBA from TAMAHAGANE or OROSHIGANE.

[GRC]

Here’s a nice example of a ko-akasaka seppa-dai that shows the four layers on the outside edge of the sepa-dai. It even has a split along the middle layers like the tsuba that started this thread… but nowhere near the same level of separation.

Regardless, the whole notion of a “three layered construction” needs to be tossed aside.

i’m still leaning toward a few freeze thaw cycles affecting the “tokkei” one, but who knows.

[ROKUJURO]

19 hours ago, GRC said:

.....i’m still leaning toward a few freeze thaw cycles affecting the “tokkei” one, but who knows.

Glen,

"frost-bite" on TSUBA is possibly an often overlooked cause of damage.  I could imagine a water-soaked TSUBA being carried a few times from KYUSHU to HOKKAIDO and back.....