Vacuum Stabilizing discussion

[HallHandmade]

I've been reading up on stabilizing, because I am very interested in setting up to do it myself. Just a quick background, I spent 10 years working at a company that manufactures industrial high vacuum equipment and controls, and several years at an aerospace company, working in composites (resins, vacuum molding, etc.). I also have many years experience working with (and storing, and curing) various local and exotic woods, as I did musical instruments as a hobby before I got into knives instead. I'm also in a terrific area, since I live in the desert I've never had many problems with excessive moisture content in my stock.

I know that people are usually discouraged from DIY stabilization, but I feel I have the professional experience necessary to do this properly once I have time to learn the peculiarities of specific woods I'm working with. Most of my experience is in research and development, specifically design and production of prototypes, and developing repeatable manufacturing processes for them. I can completely understand why it would be most practical for the majority of people to not take this on, and just send stuff out instead. That said, I'd still like to give it a try.

I have read many different things on this subject, with postings and info going back over a decade, but a few things stuck out for me. One thing I've never seen mentioned so far is temperature control. If you were to put a fairly wet piece of wood in a vacuum chamber, it would freeze during pumpdown, due to evaporative cooling. Any time you try to outgas water from something, you have to be very conscious of freeze-up or you will have poor results. The ice will eventually subliminate, but it will take essentially forever compared to a temp controlled process.

This presents a bit of a conundrum, since the resins that I've seen people refer to are generally heat cured, you can't heat to assist in outgassing when doing the traditional DIY submersion method. This may be the reason I've seen mention that the professional places introduce the resin after outgassing the wood. Gentle infrared heating during initial pumpdown of the wood should make for a faster and better quality stabilization process. There are infrared heaters available that are meant specifically for use in this application.

I've also seen mention of use of pressure, but I'm still trying to figure out why. Once the piece is fully de-gassed (well, nothing is really ever fully degassed, but at least within reason), atmospheric pressure and capillary action should really be enough to do the job. I suppose if the wood was extremely fine grained, the viscosity of the resin could have an effect on the rate at which it migrates into the wood, in which case a pressure assist could be of benefit, but I can't really think of any other reason. I suppose if a wood had some type of enclosed inclusions that were resistant to outgassing, very high pressure could help to "crack" them, but I am not incredibly sure on that one.


The results that people are getting with the "Cactus Juice" brand resin look quite good, but I'm not sure whether there is something more "professional" I should be trying to work with. I've seen that there's a few resins that have been used in the past, but opinions on them become more mixed as you go forward in search results.

 

[Stacy E. Apelt - Bladesmith]

I would recommend you contacting Mark at Burl Source. He did his own stabilizing, and now sends it out...... and he runs a wood business.

The monomers and acrylics used to do it right are expensive and have a short shelf life. Home brews made with Minwax or Cactus Juice are attempts to imitate true acrylic polymer stabilization, but the results are not the same. The equipment is the least of the problems.

 

[Burl Source]

The equipment and procedures are just part of the equation.
Getting good, complete penetration is just the start.
Different woods are going to react differently to the chemicals.
Some oily woods and fragrant woods can have difficulty with the stabilizing agent curing to a solid.
The long time professionals have spent a lot of time experimenting with different recipes and are very tight lipped about what they use.
Plus, one recipe does not work for everything.

When you finally work out the details and find a mix and procedure that gives complete penetration and sufficient hardness when cured, then your concerns will be how it works out when machined and sanded. Will it clog sanding belts? Can it be finished to look better than natural wood. Stuff like that.

If you have the time, equipment and money it can be fun to experiment. But it is a nasty, noxious procedure in my opinion.
I did my own stabilizing for a couple years and did pretty well with some woods.
But.....when I started having K&G do the stabilizing for me I found that the stabilized wood turned out better and I was paying them about the same as what I was spending on chemicals alone. It was a no brainer to quit doing it myself. They have been stabilizing knife handle woods for decades so they better be good. A lot of stabilizing companies start up and then disappear within a couple years.

I don't mean to sound discouraging, just realistic. I have ruined more good wood than most people will see in their lifetime.
If you still want to give it a try, the easiest woods to stabilize are Maple and Box Elder.

 

[Alpha Knife Supply]

If you are going to stabilize your own wood:

1) Read Mark's post several times. Try hard to understand what he is telling you.

2) Buy a good moisture meter ($150-$400). Don't rely on your environment to control your moisture content. Professional stabilizers never stabilize wet wood.

3) If you cannot understand why professional stabilizers use vacuum and pressure, you should not be stabilizing. The pressure used is substantial (more than 1,000 psi) and can kill if proper equipment and procedures are not followed.

You wrote that you "have the professional experience necessary to do this properly" but you your comments illustrate you don't understand two critical factors of stabilizing. I'm not trying to be harsh but you need to take off the rose colored glasses and recognize you have areas of weakness in your knowledge of stabilizing.

One last point. In my opinion, Cactus Juice and professional stabilizing are mutually exclusive.

 

[Willie71]

Just to add my $.02, I have ordered cactus juice to do some box elder and spalted poplar. I understood they took to the cactus juice well. I don't think it would work well on tropical woods though.

 

[Bob Katilus]

Just to add my $.02, I have ordered cactus juice to do some box elder and spalted poplar. I understood they took to the cactus juice well. I don't think it would work well on tropical woods though.

I bet it would work better in tropical drinks instead of knife handles

 

[Don Hanson III]

I did vacuum stabilizing many years ago.

Now I send wood to K&G, it's done right and is cheaper in the long run...

 

[HallHandmade]

I would recommend you contacting Mark at Burl Source. He did his own stabilizing, and now sends it out...... and he runs a wood business.

The monomers and acrylics used to do it right are expensive and have a short shelf life. Home brews made with Minwax or Cactus Juice are attempts to imitate true acrylic polymer stabilization, but the results are not the same. The equipment is the least of the problems.

I gave Mark a call earlier per your advice, before I saw his reply to this thread. Thanks for the tip. I assure you that I am not approaching this lightly. I have seen the abysmal results of the last 10 years or so in stabilization startups.

Just for the record, I have absolutely no commercial interest in this at this point. It is just a challenge for me, and something I could use to occupy my time between knives. If I have some level of success, I may do some pieces locally just to help pay for my efforts. If this does eventually develop into a commercial interest, then it will do so on its own, but for now I am just going to be doing this for personal use and education.

Other than general interest, one of my main personal goals in knifemaking is as much self-authorship as I am capable of at any given time. Even if I use other people's stabilized woods for most of my work, I'd still like to take a crack at it.

.....

Mark,

Thanks a bunch for your time earlier. I had a good time talking to you about stabilization and many other things

If you are going to stabilize your own wood:

1) Read Mark's post several times. Try hard to understand what he is telling you.

My entire career has been spent doing research and development, much of it related to polymers and their implementation. Specifically, critical bonding of optics and optical assemblies, and polymer based solid rocket fuels, incendiaries, and explosives. Both involve similar headaches to those one would experience in wood stabilization (which means more than one can easily count, either way)

2) Buy a good moisture meter ($150-$400). Don't rely on your environment to control your moisture content. Professional stabilizers never stabilize wet wood.

I have a high quality moisture meter, I did musical instruments before knives, and have a small personal stock of exotics/tonewoods/hardwoods.

3) If you cannot understand why professional stabilizers use vacuum and pressure, you should not be stabilizing. The pressure used is substantial (more than 1,000 psi) and can kill if proper equipment and procedures are not followed.

I don't think it is "cannot understand", more "do not understand". I'm just questioning whether pressure is an absolute requirement other than for expediency or in special cases.

Regarding safety, I have both vacuum and high pressure experience. I've built everything from research grade vacuum chambers (10^-10) to pressure vessels meant for characterizing explosives and rocket fuels (up to 60,000psi certified). By built, I mean that I did the design, machining, welding, and had them certified and inspected.

You wrote that you "have the professional experience necessary to do this properly" but you your comments illustrate you don't understand two critical factors of stabilizing. I'm not trying to be harsh but you need to take off the rose colored glasses and recognize you have areas of weakness in your knowledge of stabilizing.

I think you may have misunderstood my intent slightly there. I don't believe I have the experience to do it properly, in fact at this point I think almost nobody does. I think I have the experience to research what it takes to do it properly, and why, and then implement that information.

One last point. In my opinion, Cactus Juice and professional stabilizing are mutually exclusive.

I have taken no offense to your post, harshness isn't always a bad thing. This is a controversial and hazy topic, and I hope for some informative discussion of it. I really appreciate your reply. This is somewhat of a black art, which is why it interests me so much. I think I may have the knowledge and ability (especially access to specialized test equipment) to at least dig up some scraps of information to throw into the pot.

For example, I have access to a piece of equipment called a residual gas analyzer, which could be used to create an outgassing profile for different types of woods. I would be judging the wood's readiness for stabilization based upon actual measurement, not time vs. starting moisture content, which is somewhat dodgy at best. A process can be made to work by figuring out the minimum time you need given a couple other starting variables, but it's much better to measure the process in real time if possible.

The cool thing about the RGA is that it measures gasses by atomic weight in real time, so instead of saying "There's a bunch of weird crap in this wood that makes it hard to stabilize", I could characterize multiple types of hard to stabilize woods and see if there is some common thread that is interfering with uptake and curing of the stabilizing agent, and document it scientifically. Once you have real hard data like this, the polymer engineers can go nuts with it. Until then, it's just a guessing game, even for the true professionals (people with many years of experience and/or specialized engineering credentials).

The RGA is so sensitive that it can detect the oils from a fingerprint, outgassing into the chamber. It's an amazing tool. I was 2nd on a project where we were trying to determine the reason for poor adhesion in an assembly, and ended up being able to nail it down with results from the RGA scans on good parts vs. bad parts during bakeout (basically temperature enhanced outgassing). We worked with the epoxy manufacturer's engineering team to develop both a controllable cleaning process, and a special high temperature, high mechanical stability epoxy that also was able to meet NASA outgassing requirements for a space flight article that it was being implemented on.

Once we knew specifically what was causing the trouble, it was much easier to attack the solution. If someone could scientifically characterize what is happening in hard to stabilize woods both chemically and physically, and make that information public, it could shed a lot of light on the subject.

Just to add my $.02, I have ordered cactus juice to do some box elder and spalted poplar. I understood they took to the cactus juice well. I don't think it would work well on tropical woods though.

Mark had mentioned that Box Elder and Maple were two great places to start, which is nice because they are two of my favorites, and I have both on hand.

I did vacuum stabilizing many years ago.

Now I send wood to K&G, it's done right and is cheaper in the long run...

Anything I care about will definitely be sent there, until I have a serious amount of confidence in both my knowledge and ability. At this point I have pretty close to zero confidence, other than that I can crack the problem at least to some degree.

 

[Stacy E. Apelt - Bladesmith]

Some processes can be overthought...and over engineered.

When I was a chemist we regularly made wine and brandy in the lab. Some guys took the samples to the gas chromatograph and did all sorts of analysis to find out the current alcohol content and made charts predicting when it would be ready to bottle. I used a simple Brixometer and checked each morning. Some old timers just watched the bubbles. All three methods got the same results.

Wood stabilization requires the right penetrant and some fairly basic equipment. It is the skill of the person doing the stabilizing that makes the difference. If you don't do it every day for years you won't get that level of skill. That is why many people who COULD do their own stabilizing DON'T...they send it to one of the two or three people the knife making industry respects.