Help Resplitting a Shirasaya

[Curran]

Backstory:    From a local collector, I inherited a decent shinto echizen blade. Shirasaya was a mess and the patina on the copper habaki was cleaned or stripped.

I split the shirasaya parts with the old dental floss trick, and reglued with rice glue. This is the 3rd or 4th time I have had to do this in the last 25 years. It came out well.

 

Perhaps too well. Handle [tsuka] section is too tight.

AND.... during trying to loosen it, I got a piece of fine-grit sandpaper wedged inside the handle [tsuka] section.

 

I need to resplit the tsuka section of the shirasaya, but the rice glue job is too tight.

Anyone have working knowledge of how I can soften up the rice-glue to resplit the shirasaya handle?    Microwave???

I wanted to get advice here before experimenting with anything new.

 

[John C]

This may sound silly, but if the stuck sandpaper is the issue, have you tried a strong vacuum cleaner (hose) to suck it out?

 

John C.

[Brian]

Steam it open. I believe that's the approved method.

[Curran]

9 hours ago, John C said:

This may sound silly, but if the stuck sandpaper is the issue, have you tried a strong vacuum cleaner (hose) to suck it out?

 

John C.

 

Ah yes. Thank you- this is a very good idea- provided there is a enough suction. I don't have access to the lab grade hoovers of years past.

I can seal the menuki opening tightly and give it a try.

 

If this doesn't work, then @Brian steam'o'rama it will be. For a tosogu collector, this is a rare problem for me.

[Grey Doffin]

I've been waiting for the one, true answer to this; I've had the same question myself. I know from making shoji that rice glue will give with a sharp blow; you have to be able to disassemble the frame to repair damaged kumiko.  What I would try before the steam is to hold the tsuka vertical, nakago ana up. Place a hardwood block on the top of the tsuka and give it a sharp blow with a hammer. Shouldn't cause any damage and the tsuka just might fall apart.

Grey

[waljamada]

I'm glad this came up.  I used rice glue to put a split shirasaya back together but now it's a bit too tight for the blade.  I knew the best fix would be to re-split it and then reglue and not use clamps this time to hold it together while it dries to give that little bit of extra room.  I've just been displaying the blade in a glass case out of shirasaya in the meantime.    Below is the blade and shirasaya just because.

[John C]

Just to second Grey's suggestion. I had the same thought.

 

John C. 

[Grey Doffin]

Hi Adam,

About your idea to not use clamps. I've made and repaired furniture for 50 years and one basic rule is, you don't have to use clamps if you don't use glue. I think you'll regret your plan.

For clamps when reglueing shirasaya, I use masking tape over paper bands that tighten as they are slid up the saya, augmented with strips of cotton sheet wrapped tightly over all. The tape paper bands work well to keep the 2 halves aligned and leave no trace when removed.

Grey

[Curran]

On 5/6/2024 at 9:45 PM, Grey Doffin said:

For clamps when reglueing shirasaya, I use masking tape over paper bands that tighten as they are slid up the saya, augmented with strips of cotton sheet wrapped tightly over all. The tape paper bands work well to keep the 2 halves aligned and leave no trace when removed.

Grey

 

This is exactly what I do, using bluetape over paper bands done in spiral and counter spiral binding.

Then some cotton binding around this while it sets. I don't want too much direct pressure in any one area.

 

I ended up steaming and using the dental floss trick until I could get enough purchase to ***slowly*** split it with a large [wedge-like] flatblade knife we own. I had to be careful, as I have seen other people have the wood split unevenly. Striking the tsuka on the nakago ana side up would make sense in many cases. This particular tsuka has a ridiculously thick horn ring around the nakago ana section, so I preferred to work from the other end and see if I could split it and wiggle out the sections without damaging the very thick horn ring.

 

Thank you gentlemen for the input.

Tomorrow we will see if my 2nd attempt is a better fit.