lacquering question

[sporndackel]

Hello all,

 

the topics seem to be more about fittings but maybe somebody can help me solving the more "philosophical" question how to go further restoring an old saya.

I bought it together with a blade which I planned to "misuse" to replace a shorter, broken one.

Once received, I felt a bit sorry for the badly treated parts (rusty, damaged, broken, ... ) and started restoring the parts.

Yes, it is just wood and horn, but it is also interesting to "explore" the parts.

 

What I found was:

1. the saya seems to be "cut" (maybe together with the blade?), since removing the cover at the lower end shows a hole (in the form of the cross-section of the blade). I would have expected an even surface of wood.

2. the saya was painted with black urushi, but under the top layer there are several other layers, including one with a kind of nanako-nuri (I don't know actually which type of grain they used, all in irregular shapes)

3. horn application with horn in a shaded, light colour, not black (as I would have expected)

 

The question for me is now, how to go further lacquering it again:

- try to restore the first design, with the nanako-nuri style?

- go the Rolling Stones way ("Paint it Black")

- and how the treat the horn parts, leave it "natural" or cover it with (black) lacquer (again)?

 

Any opinions?

 

Kind regards

Roland

 

[DoTanuki yokai]

When looking at it I can imagine that what looks like nanakonuri is just the appearance of the lower and foundation layers that come to surface irregulary but I can’t really see much in the picture. 
 

For your question i would say do it in the style you are familiar with and don’t stick to the old design. 
At this point you will have to lacquer the complete saya and I would make the horn parts in same or fitting color. 
I don’t know what color for the Saya would be fitting with unlacquered horn. 
 

What kind of lacquer do you plan to use ? 

[Larason2]

To do justice to the piece, you should lacquer it using urushi, and unless you are already very experienced, should probably be done by an expert (but that won't be cheap!). It is typical for urushi to be applied in layers of different colour, each corresponding to different grades. It looks like a lot of it has been worn off, probably through damage. The base coat/coarsest urushi is usually a grey colour, and here it looks like the layers were a light brown, dark brown and then finally black. This corresponds to different grades of urushi as well.

[OceanoNox]

The urushi coating process appears to take more than 20 steps, with sufficient drying in a "muro" (humid chamber free of dust). Last time I had a saya made, it took one month, and it was a "simple" ishime finish.

There is an interesting article on one urushi technique: The Kyushitsu technique demonstrated on a natsume, by Shogyo Ohba (Proceedings of the urushi study group, The Getty Conservation Institute, 1985)

 

About your questions, as far as I have seen, kurikata are covered with urushi, but I do not know if the process is the same as for the rest of the saya. Unless you know what you are doing, I'd recommend against working on this saya by yourself, but you can always try your hand on a piece of wood to see what effect you can get.

 

 

[1kinko]

If you are at all allergic to poison ivy, working with urushi will be a big mistake. If all you want is a black lacquered saya, cashew lacquer will do just fine. It is really aromatic and should be done outside, but you can add dried urushi granules for an ishime finish or polish it for a high gloss. It dries very quickly and makes a very hard finish. There are premixed shitogi undercoats as well. Many other colors are available.

[Larason2]

Most people are allergic to poison ivy! The contact reaction you get to poison ivy, you will probably get with urushi. For that reason, it is difficult to work with. The guides I've seen online suggest to use gloves, but not sure if that totally prevents the contact dermatitis. You also need the special moisture controlled box, as commented on. It is also extremely time consuming to polish between steps. So, it's not easy to work with, but it is the original material, and in my opinion, the most beautiful. Definitely not for everyone though. If you just want a black finish, you can just get a black lacquer at your local big box store, and you can even spray it on.

[1kinko]

Only about 8-9% of the population is not allergic to urushiol. I am allergic but I thought I could get around it by wearing gloves. I also completely covered my arms and chest with plastic sheeting. I never had direct contact with usushi.  I turned bright red for about a week and even the bottom of my feet itched. The only relief was to take a very hot, nearly scalding, shower. Apparently, I was exposed by inhalation. Cashew is a much better lacquer than western black lacquers.

[DoTanuki yokai]

If you work with urushi you should always have some oil (I use cheap sunflower oil) near to clean it from your skin because water won’t wash it off. I always wear gloves and sometimes I get it on my skin but never had a reaction. 
I’m not sure if I’m allergic I never tried on purpose to find out. 
But actually the cashew in the  lacquer is only there because what they take from the cashew nut shell is cheaper then the synthetic alternative. 
 

I have never used cashew lacquer but I think it is like most Polyurethane based lacquer ? 

[Larason2]

Apparently if you keep working through the discomfort and itch, you eventually become immune to it. Doesn't sound like fun though!

[1kinko]

If that were true, urushiol would be the 1st allergen to not induce t-cells.

[Larason2]

A lot of saya and Japanese armour makers have claimed this has happened to them. It doesn't mean that T cells are not induced, but rather that the T cell mediated response is downregulated with continued exposure over time.

[1kinko]

I’ve read that too, but it makes no biological sense.  

[Larason2]

What about this paper?

 

https://www.nature.com/articles/s41577-019-0221-9#:~:text=It is widely accepted that,to chronic antigen stimulation4.

 

Seems to make biological sense to me.

[1kinko]

Maybe for chronic viral infections and some cancers, but there were no citations concerning contact dermatitis or urushiol. I gave up a few years ago and I see nothing new has been developed since Hapten Research at Ole Miss thought they had a vaccine that might work. That was back in 2015-2019 when they predicted a vaccine might be available by 2024, but a Google Scholar search reveals no published papers (either old or new). This strongly suggests they were unsuccessful. In 2021 a (short) Scientific American article reviewed the available research and noted that interleukin 33 is also involved.

[sporndackel]

Thank you all for the input. 

I wanted to be sure before I start to experiment with a new design that I not completely off the path.

 

Don't worry, the urushi part is familiar to me. I'm aware of the urushiol reaction. 

My "targets" for urushi are dishes, plates or grips usually, a complete saya would be a new experience.

(Good not to start with a katana saya ....  )

 

But as I said at the beginning: What could go wrong with this type of rotten peaces?  

I'll post the results.

 

@Arnaud: thank you for the hint with the urushi book!

 

[sporndackel]

Hello all,

the "saya experiment" is done. 

A little contribute to the first attempt on the older, lower layers of lacquer.

After removing and flattening all, the new layers consist now of:

- shibo (2x, just to be save)

- kuro-nakanuri layer

- white urushi (which is more ebony actually, but fits better to the old samegawa)

- suzu-fun tin powder

- kuro-nuritate (4x)

- kijomi plus polishing 

Now it looks a bit prettier, with all the damages and broken parts repaired.

Thanks again for the support.

Roland