Saya wood type

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esoo

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So does the type of wood in a saya make a difference if you're storing the knife in it?

The reason I'm asking is that I know I've stored a knife for a longer period in a poplar saya and had no issues, but I just pulled a knife out of a carmelized maple one to discover this on the spine:
20211020_211321.jpg


This appears to be rust. This knife went into the saya after a polish and has been in the saya for under a month.
 

KnightKnightForever

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Yes, if the wood is still green, or wasn't dried properly to between 0-5% moisture content, it will continue to hold moisture. Sayas don't necessarily need to be stabilized, but they should be properly dried. Also, user error can also come into play, as moisture can easily be transferred from a knife that wasn't dried properly to the internal cavity of the saya, and remain there, in essence "baking in" the moisture to the knife as it sits in the saya. For long term storage, thoroughly drying the knife, coating it in oil, and storing it in a more airtight environment is recommended - as wood is a living vessel, constantly taking in and releasing moisture as it acclimates to the surrounding environment. And as far as if the species of wood matters in terms of this particular issue, I would say not... the treatment of the wood and its environment are far more important. Softwoods do have larger cells to retain more moisture, however.
 

esoo

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In this case, I’m positive that the knife was dry before being put into the saya (the knife had been polished and unused for at least two weeks before it was put into the saya)

Longer period here meant three weeks, which to me is not excessive to have a knife sitting in a saya. This was due to the fact that I’m waiting on a box for the knife (bst purchase that came without box). The weather has also not been overly humid as I’ve not had to worry about any of my knives and rust.
 

zizirex

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my only guess is the wood is still "wet" when worked on. Also, some wood is really susceptible to humidity moisture level change that could lead to expansion and shrinkage.
 

Jovidah

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From experience, Titebond III is corrosive even when fully cured. Slightly acidic iirc. If the knife came into contact with glue residue inside the saya, that could have caused the rust as well.
Some aggressiveness is to be expected with a name like that...
The name's Bond. Tite Bond.

Sorry I'll see myself out.
 

birdsfan

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I have also heard that the Titebond type2 can be corrosive. I have been using the original formula for several years, however, without incident.
 

Luftmensch

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So does the type of wood in a saya make a difference if you're storing the knife in it?
Yes! And... no!!

As others have said: no, treating wood properly is probably the first priority. Not only properly drying the wood... but also applying a proper finish.

After that: yes, wood can be naturally acidic. Some species are more acidic than others. I believe woods with higher tannin content will be slightly more acidic.

If you plan on deep storage, a pale wood that has been properly dried and stabilised will be a safe option. If you are happy to monitor your knifes condition regularly, use any wood you please with drying oils or polyurethane as a surface barrier for moisture.

The inverse of that: untreated woods with a high tannin and moisture content are probably a bad idea....
 

esoo

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Thanks for the info everyone.

As this was an "off the shelf" saya, I'm not sure of the glue or how the wood was when worked. Ultimately for me the end result is somewhat disappointing as the goal was to use the saya to help store the knife in the saya in my knife roll for a time rather than using a box.
 

captaincaed

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Knives shouldn't be stored in saya - only from point A to B, then come out again. Even a bone-dry saya will attract moisture (put it in the toaster oven for 10" on low, it'll fog up).

Now that it's rusted once, throw the saya away. Rust is a seed crystal for more rust later, and any rust in the saya will catalyze future rust. You can cut or scrape it out, but it's difficult, risky, and the knife is more expensive.
 

esoo

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So I sent the store an email about this and apparently the maker uses a kiln dry method to dry the wood and they are bone dry when they come out. However they did say this has happened before, however rarely.

Knives shouldn't be stored in saya - only from point A to B, then come out again. Even a bone-dry saya will attract moisture (put it in the toaster oven for 10" on low, it'll fog up).

Now that it's rusted once, throw the saya away. Rust is a seed crystal for more rust later, and any rust in the saya will catalyze future rust. You can cut or scrape it out, but it's difficult, risky, and the knife is more expensive.
Part of me storing the blade in the saya was that I don't have a box for the blade. It was a new to me blade off BST without box. I've arranged to get a box for it.

As for throwing out the sayas, this saya was brand new (it was bought, the knife went in and this happened). Also, a month before I bought another saya from the same vendor/maker and I discovered yesterday it happened to the other knife, so I've got two that have the same problem. It's not a lot of money for them but it just would suck to have just bought them and then throwing them.
 

BillHanna

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Maybe a layer of VCI, then into the saya? At least until you can bear to pitch them.
 

captaincaed

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As for throwing out the sayas, this saya was brand new (it was bought, the knife went in and this happened). Also, a month before I bought another saya from the same vendor/maker and I discovered yesterday it happened to the other knife, so I've got two that have the same problem. It's not a lot of money for them but it just would suck to have just bought them and then throwing them.
Yeah I totally feel you. I had to fight this feeling myself with a couple saya. One group that deals with this is sword owners - those saya are really hard to replace, so they created scraping tools from copper tubing with a sharp, bent edge, but it’s an iffy process. If you miss some rust, you’ll just make more. Rust is a chemical catalyst for more rust, unfortunately one pin-prick is enough to get the reaction spreading again. It’s metallic cancer. It’s only cured with chemo (neutralizing acids that get on the blade) and surgery (grinding/cutting it out of the metal/wood) or it spreads.

If you want to go nuts, you can buy some electric heater bars like those used in gun safes to prevent moisture from building up. That may allow you to keep knives in the saya at home, but it’s an expensive solution.

With regard to wood moisture, kiln drying doesn’t matter. Wood equilibrates to local atmospheric humidity. If you build fine furniture in a desert, then move it to a coast, it can literally blow itself apart at the seams from the stress induced by taking up atmospheric moisture. It’s just a property of all woods. Not that your saya will explode, but it will absorb moisture to equilibrate with the local air, then hold that moisture around the knife.


You can also go stainless, I hear MagnaCut is nice 😁
 

esoo

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If you want to go nuts, you can buy some electric heater bars like those used in gun safes to prevent moisture from building up. That may allow you to keep knives in the saya at home, but it’s an expensive solution.
My solution was trying to be saya + knife roll for store not in use knives. Easy and convenient in the kitchen rather than having all the boxes. Going to have to re-think that idea now.

With regard to wood moisture, kiln drying doesn’t matter. Wood equilibrates to local atmospheric humidity. If you build fine furniture in a desert, then move it to a coast, it can literally blow itself apart at the seams from the stress induced by taking up atmospheric moisture. It’s just a property of all woods. Not that your saya will explode, but it will absorb moisture to equilibrate with the local air, then hold that moisture around the knife.


You can also go stainless, I hear MagnaCut is nice 😁
In my locale, people will talk about how humid it is in the summer, when it hits 80+%. The thing is that now we are getting into the cooling days of fall, where people think it is dry, it really isn't. As the air cools, relative humidity increases just by the cooling - it is a 87%RH this morning as I type this. This will be my problem until the furnace has been running for a bit and we fight to get the household humidity up to 20% or higher.

As for MagnaCut, I would manage to find the budget if say I were offered one by Devin. In the meantime, I've got a REX121 on its way to me....
 

VICTOR J CREAZZI

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If the rust stain is only at the spine, I would suspect the glue being the cause. Not that the exact cause matters much at this point.

I store my 'go to' carbon knife in its saya, which is screwed to the side of my knife block. I've not had any rust issues, but I do use the knife daily.
 

esoo

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If the rust stain is only at the spine, I would suspect the glue being the cause. Not that the exact cause matters much at this point.

I store my 'go to' carbon knife in its saya, which is screwed to the side of my knife block. I've not had any rust issues, but I do use the knife daily.
I have asked the vendor regarding the type of glue being used. These sayas are also magnetic, so the spine is pulled against the saya.
 

captaincaed

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They're all acidic. I'd say 2 and 3 aren't even very different. Original a little less so, but still acidic enough for rust. Sounds like you may want to do a sparse glue job to minimize squeeze-out on the inside of the saya - just enough to hold things together. Not really a joint that'll see much stress anyway. I'd say a good, dead-flat glue surface would be the ticket. Maybe even a couple pins as mechanical fasteners.
 
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