Casting a copy of a sword blade for fixtures

Hello, I am looking for a bit of advice on a project I have been asked to look into.

A friend owns a very old katana. The blade is in good condition but the handle, scabbard and various fixtures are all worn and need replacing.

He has a contact in China who can apparently make all the necessary parts and fit them to the blade.

He does not want to send his very expensive blade to China in case it gets lost or damaged.

He has asked if I can cast a copy of his blade which can be sent overseas for all the parts to be made to measure.

I initially looked at polyurethane and silicone, two materials I have never used before. I was advised that the length and thinness of the blade would make it difficult to cast and anything that long and thin in polyurethane would most likely warp.

I have looked into sand casting in aluminium and the concern is that as the metal cools it might shrink in length. Also sand in contact with a highly polished blade is not desirable and any moisture is not great for the blade.

I have been asking around on the metal working forum and there have been great ideas about how to make copies, either a blacksmith copying the blade or making it in wood or another material. Any handmade copy would have to be scarily accurate in order for the parts made overseas to be a tight fit, I am not sure that we could alter them much over here if it was a little inaccurate.

We did look into 3D scanning the blade and then 3D printing it but the local options required making multiple parts and then gluing them together. Sending the files overseas to get printed is an option but if anything goes awry then there is not much comeback. At least if we can hold the copy up to the original we will know if it is accurate.

I still like the idea of resins of some description. I am not sure if they can be strengthened or even if a metal rod could cast into the copy to make it less likely to warp.

The only part we have is the blade at the top!

Everything else has to be fitted to the blade so we are looking for a very accurate copy.

Attachment 428789

I am happy to give it a go and see how it turns out, however the cost of silicone and polyurethane combined with the number of attempts that it is going to take me means that it is all going to add up pretty fast. It also might not be the best way of proceeding. The owner likes the idea of sand casting in aluminium, this might be fine for the relatively short and thicker handle but not sure how it would affect a metre or so long thin blade.

Happy for any ideas or advice on the best way to proceed.

If you fancy having an attempt at making this I would love to talk to you! We are in the North Brisbane area but happy to travel and cover all costs for materials, time and expertise, it will be cheaper and do less damage to the sword if someone who has a clue has a go.

Thanks for taking the time to read and consider this request.

Cheers
Mark

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Originally Posted by Jislizard

A friend owns a very old katana. The blade is in good condition but the handle, scabbard and various fixtures are all worn and need replacing.

He has a contact in China who can apparently make all the necessary parts and fit them to the blade.

He does not want to send his very expensive blade to China in case it gets lost or damaged.

He has asked if I can cast a copy of his blade which can be sent overseas for all the parts to be made to measure.

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the problem I see with this approach is that the handle in particular will be fitted to the cast.
How do you then get the handle off the cast and onto the real blade?
If the handle (grip) is fitted like I think it is -- i.e. built onto the blade's tang -- then I can't see how it could be removed without taking it apart.

I would think making a wooden replica to which the new scabbard could be fitted would be relatively straight forward, but the handle ...

Quote:

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Originally Posted by ian

the problem I see with this approach is that the handle in particular will be fitted to the cast.
How do you then get the handle off the cast and onto the real blade?
If the handle (grip) is fitted like I think it is -- i.e. built onto the blade's tang -- then I can't see how it could be removed without taking it apart.

I would think making a wooden replica to which the new scabbard could be fitted would be relatively straight forward, but the handle ...

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The Japanese strip their swords down for cleaning on a fairly regular basis. The actual handle has a hole drilled through it which matches a hole drilled through the tang.

The whole thing is held together by a small bamboo dowel, sometimes two depending on the maker. They don't often come apart in mid-swing but it has happened. Checking the dowel is one of the first things you do before practice.

The two sides of the handle are lightly glued with a rice startch glue and then held together by the ray skin (for grip) and the decorative ribbon which is actually holding the whole thing together.

Apparently back in the day, when fashions changed you just changed the handle and scabbard to match the latest trend but still got to use your same blade.

My thoughts would be, as you only need thetang and a short piece of the blade, I would suggest a silicone mould with ahard case. Place it into a decent size pressure chamber. This should give you afairly accurate mould. The mould would only need to be the length of the tang and 50-75mm of the blade

You could then fill the mould with a resinor plaster of Paris, (porcelain).

Then do a dimensional check on both thekatana and the model. See how close it is

Kel

Is there a reason why it wouldn't be sent to Japan for such a service?

Surely there is a local person if there is a problem with its acquisition....

Quote:

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Originally Posted by nivlek

My thoughts would be, as you only need thetang and a short piece of the blade, I would suggest a silicone mould with ahard case. Place it into a decent size pressure chamber. This should give you afairly accurate mould. The mould would only need to be the length of the tang and 50-75mm of the blade

You could then fill the mould with a resinor plaster of Paris, (porcelain).

Then do a dimensional check on both thekatana and the model. See how close it is

Kel

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He is looking for the wooden scabbard as well so the full length would be needed. Plus it makes a nice sweep from end to end so it is all made at the same time. However just a really accurate tang would probably be useful as well.

Cheers
Mark

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Originally Posted by woodPixel

Is there a reason why it wouldn't be sent to Japan for such a service?

Surely there is a local person if there is a problem with its acquisition....

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The owner is a bit wary of someone pulling a switch and substituting another blade. Particularly if they think that the western owner would not notice the difference. I don't know how likely that is to happen but that is one of the main reasons why he doesn't want the actual blade to be sent overseas. Other than just getting lost in the post.

I am sure there are plenty of people over in Japan who would be able to do the job and he is heading over there in March so if he wanted to I am sure he could.

Cheers
Mark

There are bladesmiths in this country who can do what you are looking for without casting parts etc. Join Australian blade forums and make a post.

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Originally Posted by Canisbellum

There are bladesmiths in this country who can do what you are looking for without casting parts etc. Join Australian blade forums and make a post.

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Thanks, nice idea, will head over to https://www.australianbladeforums.com/vb4/ and join up.

Cheers
Mark

Substitution is extremely unlikely if (for want of a better word) high end makers are used, Japanese at this level are very honorable individuals, while one or all of these artisans may consider a westerner should not be the custodian of a
valuable heirloom they would never attempt to acquire such by deceit.
However one may offer to purchase the item back

Quote:

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Originally Posted by China

Substitution is extremely unlikely if (for want of a better word) high end makers are used, Japanese at this level are very honorable individuals, while one or all of these artisans may consider a westerner should not be the custodian of a
valuable heirloom they would never attempt to acquire such by deceit.
However one may offer to purchase the item back

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I do not think it highly likely either.

Cheers