Stabilized Wood – Fact vs Fiction

[Alpha Knife Supply]

Over the last few years of selling stabilized wood I’ve developed a theory. I’m still collecting data so it will remain a theory for a few more years. I would like to know your experiences.

I think the key to any wood remaining stable is: moisture content.

We do all the work on most of our wood. That means we:
- Buy the raw lumber
- Cut the lumber into blocks
- Kiln dry the wood blocks
- Let the wood “Normalize”
- Send in the wood for stabilization
- Let the wood cure after stabilization
- Sand the wood to size
- Buff the wood
- Grade the wood to determine pricing (or if it goes into my private stash )

All through the process we use a digital moisture meter to measure the moisture content. Almost every block of wood gets checked five or six times. Mike Ludeman at WSSI will not stabilize wood unless it contains 12% or less moisture. We used to use 12% moisture as our maximum but now we prefer to be at 6% or less.

The reason we lowered our maximum was because of woods like redwood burl. Some of the wood containing 12% moisture warped and/or twisted when stabilized. To get the block square we ended up with an undersized block and lots of expensive sawdust. When we reduced the level to 6% the wood moved much less. I think the stabilant displaces moisture, causing the wood to move.

We have a process we call Normalizing. We consider a block of wood to be normalized when it can be moved between the kiln and storage and have no change in moisture content. Some woods take years to normalize. Ebony and snakewood are two examples. We have pieces that have been in the kiln and back into storage more than five times over two years; the moisture content still changes. We will keep working until this wood is normalized. I’m sure these pieces would move around if put on a knife, perpetuating the bad stereotype.

One test we tried was determining moisture content by touch or feel. We took turns estimating the percentage and then measuring to see how close we were. The test was a complete failure. Two pieces of wood from the same burl, cut at the same time, processed the same and feeling the same can have radically different moisture contents. We still try this test occasionally, but the results are always the same.

We built our own kiln. It is a critical tool for drying wood. It contains a heater, dehumidifier, a thermostat to control the heat, a thermostat to control internal/external air exchange, a humidistat and three circulation fans. We start with the temperature around 120° and the humidistat turned all the way up. Every few days we turn the humidistat down a few points. Every two weeks we pull a sample and test the moisture content. If we try and dry the wood too fast it honeycombs, and then is expensive firewood. When the wood moisture content stops changing, or gets down to 6%, we empty the kiln and let the wood sit on the shelf for a few weeks. If the moisture content has not changed, it is ready for stabilizing. If it has changed, it goes back into the kiln. I think the reason for the change is due to unequal moisture content in the block. We’ve noticed most woods are significantly harder when removed from the kiln for the last time.

My recommendation to knifemakers is to buy wood from us and let us worry about the problems. If you don’t want do that, buy yourself a good digital moisture meter. I don’t mean a $29.99 special. Good meters start at about $100-$120. If you are making knives with wood handles, this tool is as important as any other measuring tool in your shop. Do you make knives without measuring? Why wouldn’t you want to know the condition of your wood? Check all your wood and keep track of the moisture content. Dry your wood thoroughly before stabilizing, even if your stabilizer is a mason jar filled with stabilant and a hand pump.

If you keep records about the knives you make, include information about the handle. This information may help you resolve future problems. As a maker, I would want to know: where the wood came from, how the wood was dried, moisture content, who or how the wood was stabilized and how it was finished.
If customers call with problems, look at your records to find the pattern. If the pattern is, all the wood was purchased from the same supplier, call the supplier and let them know. The supplier should then do more investigating to determine the root of the problem. The point is, without data you will not find the pattern and you will have to guess. I think this is how some of the urban myths about stabilized wood have started. It is much easier to blame the wood than the process.

Some of you may wonder why I’m telling you what I’ve learned. The knife buyer deserves the best quality possible. When a customer posts a problem with his wood handles moving or shrinking, it casts a negative light on all of us, guilty or not.

If you have any questions or comments feel free to call, e-mail or start flaming.

 

[Protactical]

Is your stabilizing process saturation with some resin? That should do it.

One always has two choices, the techno approach, or the skills approach. You can turn wood into a plastic, and I think that is a very good idea in certain cases, or you can use standard woodworking knowledge to deal with wood movement, which will also work.

 

[Alpha Knife Supply]

Thanks for the question Protactical. I should have clarified.

We do not stabilize wood ourselves. We send the wood to WSSI for stabilization.

 

[Mike Hull]

Chuck, I was talking to Judith Mattart(The Lumberlady)some time ago, she revealed that they had started having greater success drying wood, if they let it cycle, like in nature. Hot, then cold, like day, followed by night.
Just a thought.

I think there's something about it here. Scroll down to "kiln drying".
http://woodworkersworld.homestead.com/fall_2002_p1.html

Thanks for your informative post.

 

[mattd]

Thank you for that post! It answered many of my questions about wood stablization.
Even though your operation doesn't do it, is there a way to stablize a few pieces of wood yourself? I'm kind of looking for one of those backyard, do it yourself, find the parts at a garage sale type set ups that this forum is famous for. Thanks

Matt deClercq

 

[TimWieneke]

Without stepping on too many toes here, I just want to bring up a point.

In addition to my love of knives, I am a gun collector. I have a Colt Model 1910 .45 revolver that through research, I found was likely manufactured at the factory in 1911 or 1912. Anyway, through further research I found that the grips on this pistol are original. Now, I've read these pistols were built for the marines (Was it the Phillipines conflict or somewhere around there?) but I cannot say for certain if this one actually saw action. Anyway, after years of being carried, exposed to Lord knows what climate and hit with the shock of firing .45 long colts, these unstabilized, unfinished walnut grips still have a very tight fit and finish to the pistol's frame.

As Chuck alluded to, I believe that what has happened to many bladesmiths is that they were unaware of how to properly dry wood or got lazy or impatient to the actual time-consuming process of it and though stabilization would provide them a quick and easy answer. Proper drying, the species and the cut of the wood (you know the way a board gets cut from a log is different for different applications right?), not a chemical, is the key to long term fit and finish.

I've just seen too many examples of 70+ year old unstabilized woodwork that still retains superb fit and finish to believe that stabilization is the answer to retaining fit and finish. I'd need to have another reason besides this to stabilize wood - don't know what that is yet though - does it improve shock resistance? Maybe it'd be work it on a hawk handle then....

Stabilization is a good idea for some - but so is the Segway scooter. How many of you own a Segway?

Tim

 

[Mike Hull]

Originally posted by TimWieneke
Without stepping on too many toes here, I just want to bring up a point.

In addition to my love of knives, I am a gun collector. I have a Colt Model 1910 .45 revolver that through research, I found was likely manufactured at the factory in 1911 or 1912. Anyway, through further research I found that the grips on this pistol are original. I've just seen too many examples of 70+ year old unstabilized woodwork that still retains superb fit and finish to believe that stabilization is the answer to retaining fit and finish.
Stabilization is a good idea for some - but so is the Segway scooter. How many of you own a Segway?

Tim

Tim,
I have an old 1911 .45 auto, that was made in 1918, used in the last 6 months of WWI, issued to the 40th National Guard(Santa Ana, CA)
in 1925 or so, when they were superceeded by the 1911A1 version.
My friends dad carried that gun throughout WWII in the Pacific theater, made several landings etc, and "liberated" it upon discharge.
I have owned that gun since 1967, and fired it countless times. Worn it for years in a shoulder holster while dirt bike riding, next to the skin, under a jersey.
That pistol still has the original Walnut grips on it.

I think that stabilizing is great for many woods that are beautiful, but too soft for tool handles(Redwood burl comes to mind)otherwise.

It does make a good thing better when done to already hard woods, but is definitely not a necessity.

 

[TimWieneke]

"It does make a good thing better when done to already hard woods"

Ok, I think I get it. Does stabilizing preserve the look of grain patterns in say a burl better than if it were unstabilized? Makes sense then for an art knife.

As an aside, I gout a knife w/ stabilized handles to try and use in our cold, winter hunting months up here. It was a poorly designed commercial knife to begin with, but the stabilized slabs made it so slip-prone in the hand I couldn't use it for safety's sake (cold, wet fingers are the norm up here). It decorates a shelf now - so it's not a total loss I guess.

On the other hand, I had this scandanavian knife once - simple varnish finish that thankfully wore away soon - what a great using knife! Always felt warm in my hand though the wind was blowing cold.

Tim

 

[Wild Rose]

Hurrah Tim & Mike!
I too am one of those that does not consider stabilizing the answer in all cases or a necessity (dependent on the wood or other material of course). Is there a place for stabilized wood - of course there is just like there is a place for kydex or other synthetic materials for sheaths! (I can hear the cries of HERESY over that last statement coming from me

Anyway I have handled a bunch of frontier knives over the years that all had unstabilized wood or antler handles - age 100-200 years plus. Considering the age and amount of use (many of them had blades that were worn down from sharpening anywhere from 1/4-1/2" or more). The handles were all in good usable condition. So done properly unstabilized handle material will last a loooong time with even minimal care.

BTW if any of you saw the recent pic of me hanging on the wall behind my head is an old military musket - date 1820 - the wood is still in very good condition and is only about an 1/8" thick along the barrel. This gun has seen a LOT of use in the last 184 years - in fact I used it for hunting up until a few years ago when I retired it due to worries of metal fatigue - not wood fatigue.

Anyway for what it's worth that's my take on things.

 

[Danbo]

I believe the key is proper drying of the wood first also. Stabilizing does help, but some woods are so dense and oily, the stabilization can't possibly penetrate very deeply. I often wonder exactly how deep this stabilization goes into the wood. With this in mind, I wonder how many knifemakers rough grind their knife handles first and THEN send the wood off for stablization? This way, you really wouldnt lose any of the stabilizer penetration. Does this make sense to anybody but me?

 

[Bruce Bump]

The way I see this problem is the wood shrinks and exposes a sharp edge of metal which gives us the feeling of improper wood treatment. Wood by nature expands and contracts even if its stabilized (although less) I have the solution and it works perfectly. Why do we install the grips and then grind the wood and tang to size? Why dont we temporarily install the grips or scales and finish the entire handle area and then take off the grips or scales and slightly round off those sharp edges on the steel tang and the wood? Then install them permantly or with screws. What say you?

 

[Wild Rose]

The way I see this problem is the wood shrinks and exposes a sharp edge of metal which gives us the feeling of improper wood treatment.

Bruce I had this exact thing happen on a full tang Bowie when I moved from very humid Western Washington State to very dry Western Colorado - damned near sliced my hand to ribbons! The grips were permanently mounted with epoxy and pins so I didn't want to strip it - solution a Vee needle file an some VERY careful filing.
BTW the grips were stabilized stag.

Of course my final solution has always been to make stick tang knives - not a complete solution but when done right you've got less exposed edges to pull away from each other.

As to how penetrative finishes are - not sure about the polymers the pros use but some years ago I did an experiment with 3 types of typical wooden gunstock finishes: Boiled Linseed Oil, Danish Oil, and Pure Tung Oil. Took three 1" squares of very dense eastern hard rock maple and soaked them in a jar full of each finish for a week. Sliced the chunks in half: the Linseed oil had penetrated about a quarter of the way to the center, Danish oil a little over half way, and the Tung oil had penetrated completely through. Re ran the test a couple of times and each time the same out come.

 

[Fox Creek]

Bruce, I think you have made a very astute observation. As long as one requires that machine tool type fit with razor sharp 90 degree angles and "perfect" fit, there will be troubles, as anything less than perfection will look badly done. Handfinishing lets the craftsman bring those different materials together in a harmonious way that endures more gracefully. 'hard to explain, its an aesthetic attitude I guess. And Chuck, I think that a lot of the wood cut 100 years ago was far better quality than the wood cut now. like the first growth yellow poplar the pioneers built with, totally different than the second growth poplar. A lot of stuff sold now is immature, fast grown stuff.

 

[Bruce Bump]

What does astute mean?

 

[Mike Hull]

Originally posted by Bruce Bump
What does astute mean?

It's OK, Bruce. It's in your favor.

 

[TimWieneke]

Chuck,
When I bought my house last summer, built in 1929, I redid some hardwood flooring but saved the oak floorboards that were torn out. Still as tough as new and waiting for blades worthy of them. I'm thinking those babies are dried out.

"And Chuck, I think that a lot of the wood cut 100 years ago was far better quality than the wood cut now."

Reminds me of a funny experience our lead carpenter had with a young architect. Homeowner asks the carpenter if the exiting douglas fir beams in a house can be re-used as opposed to new douglas fir beams. Before the carpenter could answer, the architect jumps in "Oh don't worry - that old lumber's strong!" Carpenter gives him a look, "You're saying they don't make trees like they used too?"

If all fairness Fox, I agree with you in regards to some old-growth fir trees compared to the kiln dried spf hybrids and such that the lumber companies carry now - but that deals with rough grade fir lumber, not a trim or exhibition grade hardwood lumber. Hardwoods have a maturity age when the wood is ideal for harvesting - after that, they just get bigger, not necessarily better. I can't remember specific examples now, but if I remember correctly Black Walnut (as one example) matures at somewhere between 8 and 10 years and you want to harvest it before 25? I can't speak for exotics - just don't know them well enough.

A bigger problem for the knifemaker than lumber age is choosing wood that is cut correctly for his purposes. If you are going to spend some serious money on wood, check to see if it's plain sawn or quarter sawn. The quarter sawn is a more expensive procedure (and creates more wood waste) but gives a much tighter grain and moves less in varying weather than plain sawn.

Speaking of wood - we ran across a new type of outdoor decking material (bout a year old in our area) that seems to be popular called Brazillian Redwood. It feels like it's heavy as coccobola, tougher than oak and has a rich solid red color with a very, very dense grain. I imagine it would make a superb knife handle, but haven't had anyone order a deck made out of it yet (yeah, I'm cheap). Anyone mess with this?

Tim

P.S. Bruce - astute is what happens after you eat chili. Your as tutes.

 

[Bruce Bump]

Maybe thats why people dont stand very close to me, My as tutes

 

[John Andrews]

Originally posted by Bruce Bump
Maybe thats why people dont stand very close to me, My as tutes

LOL! I used some great looking stabilized buckeye burl on two Xmas knives, the first I have used. I was very impressed by the way the wood worked and the ease of finish. The resin went clear through, which in my views is pretty hard to beat, compared to finishes that that just have some penetration protection. Up until then, I have used just about every available product and actually had sufficient wood protection with all of them. The least protection I had was with poly finishes, with 1/8" penetration to about 3/16", but the same knives are out there year after year(hunters) and holding up well. One example of how well the polyurethene worked for me is a knife I built, a small skinner handle that had a stacked handle of osage,deer antler,brass, and 99.99 silver. The owner received the knife as a gift, and didn't realize the value of the knife. He used it one time to field dress a deer, then tossed it in the open bed of his pickup and forgot it for almost a year! Well, it was still there, all in one piece. The L6 blade was rusted, of course, and eaten up too by the gut slime and blood that was left on the blade. The knife was still in the handmade leather sheath. His brother, the original buyer, found the knife and brought it to me to see about any possible reconditioning. The handle was assembled with Acra Glas, and hidden pins. There was no apparent seperation of the sections and actually just required some light sanding and a few coats of poly finish. The blade was another story! The same knife was the first knife I have sold, and was the beginning of my custom making in '91! The guy is still using the knife for deer hunting, but I imagine he is taking better care of it now.

 

[Mike Hull]

... The owner received the knife as a gift, and didn't realize the value of the knife. He used it one time to field dress a deer, then tossed it in the open bed of his pickup and forgot it for almost a year! .... [/B]

I'll tell you, some people shouldn't be allowed to own knives, especially good one's.

 

[DaQo'tah Forge]

I have just a little question.

when you say that it very important to make sure the wood is dry,,,how do you get wood to dry?

will sitting in a shop for a few years do it?

My questions really are a concern to me because...

About 1 and 1/2 years ago a guy at work with me gave me a 6 foot long tree limb,,The limb was from a dead Black Walnut tree that his dad planted years and years ago. The tree had died and he has kept this limb for about 4 years in a shead waiteing for something to do with it.

well I found some free time and made a knife with some of the walnut.

The limb has sat in my shop all this time standing up. I used wood from the top end that was always off the floor.

I did NOT dip the wood into any type of stuff to make it hard.

I just cut a section from the rest of the limb and sanded it to handle shape..

what are the odds the handle to stay put?