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Question About Rusting and Wood-Glued Sayas

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JAMMYPANTZ

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Hi everyone!

I'm not sure if this has been answered on the forum (I'm sure it has and I'm too lazy to look haha!) - I just finished three-hours worth of annoying saya-making only to find out that the wood glue that I used (Titebond III) may cause steel to rust even after it's been dried and cured? Here and here.

IMG_0018.jpg

But apparently, wood glue has low pH, i.e. high acidity?? For those who have made their own says with wood glue (Titebond, Elmers, etc.), have you encountered any rusting on your knives? Any input would be greatly appreciated! Thanks!
 
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Bensbites

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I have not, but my sayas are only used for travel storage. I always considered the wood from sayas to hold enough moisture to concern me. I have advised my saya clients not to use them for long term storage without vci paper.
 

Jon-cal

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I haven’t experienced this with titebond. I have, however, seen certain kinds of wood cause severe reactions when in contact with carbon steel. Purpleheart in particular caused crazy rusting. Will never use that again...
 

toddnmd

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I’ll agree that the primary use of a saya is for protection in transport. Not really recommended for long term storage, particularly for carbon or even semi-stainless.
 

JAMMYPANTZ

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Got it. Good to know! I've been keeping my knife in vci paper, but good to know that sayas primarily shouldn't be used for more than transportation purposes.

Thanks everyone!
 

Bensbites

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Got it. Good to know! I've been keeping my knife in vci paper, but good to know that sayas primarily shouldn't be used for more than transportation purposes.

Thanks everyone!
FYI, Vci paper has an expiration date. Generally it is two years.
 

inferno

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i dont see how that saya/glue combo would rust the blade more or less than any other wood. drill a hole at the bottom so you can let air out if the says is ultra tight.

only thing i heard about wood rusting steel is oak and it was probably just BS.

just oil the blade, done.
 
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Titebond II & III will cause corrosion on some carbon steels. Titebond I (the original red label) is safe.
 

ChefShramrock

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I have been using Titebond III and have not noticed any issues. I use poplar wood. What other glue is recommended?
 

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I use Gorilla wood glue, as it dries clear and doesn't stain wood like Titebond products.

Also, I buy saya wood in large lots and let them naturally dry for months, even years if I can.

Lastly, I finish with many coats of Danish oil, until fully penetrated.

I am well over 400 sayas now, and have never heard of a saya causing rust. I store my own rather large collection in sayas, in a tool box. I live in the rather humid state of NC.

I would speculate that a knife that rusts within a saya had some residual moisture left to begin with.
 

captaincaed

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An unsealed ho wood saya collects moisture in my experience. If I put it in the toaster oven on low, it creates a mini sauna. Lotta steam. If I leave a carbon knife in it for weeks, it rusts. Simple as that. If rust starts inside a saya, it is a chemical seed crystal to create more rust in the same spot. Gotta get rid of the rust or the saya, if you're fussy like me. Try it if you don't believe me.

Vertical storage with air movement seems to be working well ATM. Doing a little experimenting leaving oil and and off the blades.

No experience with carbon steel in a sealed saya.
 
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I have also made hundreds of sayas and have mostly used Titebond glues. I mainly use hardwoods, mostly tropical or sub-tropical, some are kiln dried, but most are not. I also lived in Miami, less than a mile from the saltwater bay, and now I live in equally humid N. Carolina. In the vast majority of the cases where I have observed rust, it is with carbon steels coming contact with the glue, not from the wood itself......though I imagine if the knife/saya were exposed to quick extreme temperature changes, the blade may sweat and possibly form rust. I do experience this in my shop with my larger tools, such as the cast iron on my table saw when there is a change in the temp of 20-30 degrees in a short period. The real culprit is the formulation of certain glues, such as Titebond II & III....I have seen many blade develop a rust overnight due to the interaction with these glues. 52100 and TB III really do not get along. My sayas are all sealed on the out side, but the insides are not, so I am not sure if sealing the wood really matters. I do think it is important to make sure the blade is totally dry before putting it in the saya.

I now use TB I (it is a higher pH than II & III) exclusively and there are no issues. There is plenty of info regarding this, especially if you search for swords/sayas.
 

Jon-cal

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Titebond ii and iii have low pH and will absolutely cause rust if in contact with certain carbon steel. I went back and checked a few of mine after commenting that I never had problems and they did have some rust where there’s glue contact. Nothing to do with moisture. It seems most noticeable with iron cladding
 
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captaincaed

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"I now use TB I (it is a higher pH than II & III) exclusively and there are no issues. There is plenty of info regarding this, especially if you search for swords/saya."

This is good to know.
I'll double down on dry knife before saya. Hot water/IPA to make sure it dries properly.

IPA being isopropyl alcohol, not hoppy beer.
 

ChefShramrock

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"I now use TB I (it is a higher pH than II & III) exclusively and there are no issues. There is plenty of info regarding this, especially if you search for swords/saya."

This is good to know.
I'll double down on dry knife before saya. Hot water/IPA to make sure it dries properly.

IPA being isopropyl alcohol, not hoppy beer.
Thanks for clarifying. I was like, Is there nothing a good ipa won't fix?
 

VICTOR J CREAZZI

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I made a poplar saya for a very reactive carbon steel knife a few weeks ago and used Elmer's wood glue. No problems yet, though I live in low humidity Colorado.
 

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Old Head
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So when we are talking about knives coming into contact with glue, is it like glue globs seeping through the seems?

Can't this be remedied from a more careful application? Also, I usually apply an even coat of glue, and let it sit a bit before I put the pieces together. This helps keep it from sliding around, as the glue will be more tacky, and also keeps the glue from oozing everywhere.
 

FishmanDE

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So I had 5 sayas made recently. Got them back last week with my knives. Reach for a knife today and the tip and primary edge were both rusted out. Checked the other 4 and they were all the same. Reached out to the maker and he claims he used gorilla wood glue. I’m at a complete loss. None of the knives have ever been used. I also have 3 other high carbon knives with sayas and have never had any issues with them. Anyone have thoughts?
 
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I have never used Gorilla and don't know the formulation of it, but see my response earlier in this thread about TiteBond glues.....I have made hundreds of sayas and have made some sayas that do cause rust on certain carbon steels, and I then learned about the reason and found glues that work just fine.

Careful application of the glue does not matter....when properly clamped with sufficient glue to make a good bond, there will be seepage inside the saya...there is nothing that you can really do about that.....it is much easier to just use the appropriate glue. BTW, I have also used epoxy in making sayas....the seepage from epoxy can cure hard enough to cause damage to the blade.

Bottom line, use a quality wood glue like TiteBond I, or a similar quality product of the same formulation, and obtain a superior bond with no damaging reactive qualities.
 

FishmanDE

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I have never used Gorilla and don't know the formulation of it, but see my response earlier in this thread about TiteBond glues.....I have made hundreds of sayas and have made some sayas that do cause rust on certain carbon steels, and I then learned about the reason and found glues that work just fine.

Careful application of the glue does not matter....when properly clamped with sufficient glue to make a good bond, there will be seepage inside the saya...there is nothing that you can really do about that.....it is much easier to just use the appropriate glue. BTW, I have also used epoxy in making sayas....the seepage from epoxy can cure hard enough to cause damage to the blade.

Bottom line, use a quality wood glue like TiteBond I, or a similar quality product of the same formulation, and obtain a superior bond with no damaging reactive qualities.
I saw your previous post and appreciate your feedback. I guess what I'm asking is there anything else that could cause a dry blade to rust in a saya? Like maybe improperly dried wood? Or is there anything I can do to counter act the glue seepage? Would attempting to dry it out further do anything beneficial? Or perhaps application of food safe mineral oil to the interior?
 
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I saw your previous post and appreciate your feedback. I guess what I'm asking is there anything else that could cause a dry blade to rust in a saya? Like maybe improperly dried wood? Or is there anything I can do to counter act the glue seepage? Would attempting to dry it out further do anything beneficial? Or perhaps application of food safe mineral oil to the interior?
Probably not, it is a chemical reaction with the glue. A couple of things to try....I have used both....fashion a hook out of a coat hanger, you may have to thin it with a file and create a sharp point...use it to try to scrape along the glue line and remove excess glue...the other method I have used, and I think it helps, but I can't fully stand behind it....spray a lot of a rust inhibitor spray (CRC/ Boeshield) in the saya...do it in a rinse/repeat fashion a few times....again can't stand behind this since it is not food safe....but I think it helps out.

You could try something like a butcher block mineral oil/beeswax....couldn't hurt....you would just need to wipe or check the blade prior to using.

I have lived in Miami less than 1 mile from saltwater and am now in a very humid part of NC.....moisture has never been a problem, with the following exception and only in NC, not FL, a major temp change in a short period could cause the metal blade to sweat and cause some rust....that has happened in my shop that is not climate controlled like most residences are.
 

captaincaed

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Overall wood saya just don't seem to be for long term storage. The wood accumulates moisture no matter what you do.

For a fun trick put the saya inside a toaster oven. Turn it to about 200° F and watch the glass fog up with steam. Wood holds moisture. Saya are meant more for transportation than long term storage. Some people get away with storage, YMMV.

also don’t forget, that if you get rust started in the saya itself, there’s basically no getting it out and it will act as a seed crystal for future rust.

Sounds like choice of glue is a factor for thr edge. No way to prevent squeeze out except using too little glue. Would waiting a full month for full cure make a difference?

You want your knife to be bone dry before you store it especially In a wood saya,I like using hot water because when you dry it off the residual heat helps the remaining water evaporate. I also like to use a small spray bottle with 60 or 70% isopropyl alcohol. This adds some chemical drying. After that leave it on the counter for five or 10 minutes and make sure it’s absolutely bone dry before you do anything like put oil on it or put it inside of saya. Putting oil over a thin film of water on the knife will cause rust in the long term. Remember that oil is lighter than water so it’s happy to trap water between the steel knife and the oil.
 
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IsoJ

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Overall wood saya just don't seem to be for long term storage. The wood accumulates moisture no matter what you do.

For a fun trick put the saya inside a toaster oven. Turn it to about 200° F and watch the glass fog up with steam. Wood holds moisture. Saya are meant more for transportation than long term storage. Some people get away with storage, YMMV.

also don’t forget, that if you get rust started in the saya itself, there’s basically no getting it out and it will act as a seed crystal for future rust.

Sounds like choice of glue is a factor for thr edge. No way to prevent squeeze out except using too little glue. Would waiting a full month for full cure make a difference?

You want your knife to be bone dry before you store it especially In a wood saya,I like using hot water because when you dry it off the residual heat helps the remaining water evaporate. I also like to use a small spray bottle with 60 or 70% isopropyl alcohol. This adds some chemical drying. After that leave it on the counter for five or 10 minutes and make sure it’s absolutely bone dry before you do anything like put oil on it or put it inside of saya. Putting oil over a thin film of water on the knife will cause rust in the long term. Remember that oil is lighter than water so it’s happy to trap water between the steel knife and the oil.
Very good write
 

MarcelNL

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anyone using hide glue? Seems a choice fitting with the artisanal character of hand forged knives.
Am just starting to experiment with rabbit glue for my speaker project, it's been in use for thousands of years, in fact they find furniture in the Pyramids where it was used (and caseinate glue) still tightly bonded.
 
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kbright

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I've been using Tru Oil as a wood finish on sayas. It is very thin, and I pour some oil inside the saya and roll it around to coat the inside surfaces. I stand the saya up vertically and let the oil drain out. This is oil that hardens. This reduces moisture contact with the wood and glue. However, if you wipe off a blade and leave some water drops when you insert in the saya, it will trap the water inside.
 

FishmanDE

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I appreciate all the feed back! Again, knives have never been used and I have multiple other high carbon knives stored in sayas with no issues what so ever, I it seems very clear that these sayas are the root of the issue. Good idea with the oven, I’m going to give it a go right now and see how it works. I’ve also ordered knife oil to apply to the dry blades in hopes that I could potentially help “seal” the inside of the sayas as they were not finished. It might also be worth mentioning that these sayas are a tighter fit than the previous sayas I own. I wonder if that additional contact could also play a larger part
 

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