Vaccum infusion of friable wood

[rob streeper]

As I have detailed here I want to use mesquite for saw handles. The problem however is that mesquite can be brittle.

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This handle was coming along nicely and then...

So I decided to try this.

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To accomplish the vacuum infusion I first fabricated a vacuum chamber.
The necessary ingredients include 0.75" X 12" X 12" Delrin plate, vacuum bleed valve, vacuum gauge, various fittings and tubing, vacuum pump, Corning baking pan purloined from the kitchen cabinet. The fittings are plumbed into threaded holes drilled into the top and the rubber gasket material is glued to the underside using Barge Cement.

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Assembled system.

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Makes about 23-24 in Hg

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Add the broken handle, pour in the wood hardener, add a lag screw to keep the handle submerged.

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And apply the vacuum.

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Wait until no more bubbles are evolving, ~ 15 minutes, close the pump isolation valve and wait 10 minutes and then we have.

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Hang it up to dry for an hour and do some test cutting.


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Seems to cut okay but I can tell the resin is still soft. I'll leave it overnight and report on the performance tomorrow.

[Skew ChiDAMN!!]

Can you eyeball the depth of penetration into the wood from your test cuts?

Just asking, 'cos 25-30 mins is an awfully short time when it comes to vacuum work, however I haven't used Miniwax Wood Hardener, nor do I have any idea of the properties of mesquite in this situation; I mainly work with epoxy & Aussie HW where "overnight" is a more effective measure of time scale. :-

[RayG]

Hi Rob,

Thanks for posting that, I just realized that I have a vacuum tank and good vacuum pump sitting on the shelf.. my son used it when he was doing plastic molding.

I guess the time for complete penetration would depend on viscosity and how porous the timber is..

Ray

[burraboy]

Hi Rob,

Thanks for posting that, I just realized that I have a vacuum tank and good vacuum pump sitting on the shelf.. my son used it when he was doing plastic molding.

I guess the time for complete penetration would depend on viscosity and how porous the timber is..

Ray

...possibly ambient temperature too.

Keep us informed of progress rob, looks interesting. I could think of a couple of applications myself.

[Big Shed]

I watched a demo with Cactus Juice at the last penturners get together at Sturdee's place.

It was using Cactus Juice, imported from the US

TurnTex Woodworks - Cactus Juice Stabilizing (http://www.turntex.com/index.php?option=com_virtuemart&Itemid=121)

and sold in Oz by Mark at 043Turning.

Quite impressive results on punky timbers.

[planemaker]

On another forum site Dominic Greco used Minwax Wood Hardener as the resin to vacuum impregnate some punky timber with the following results.


Eric,
To answer your question, and to echo the reply of some others here, Yes you can make a vaccum chamber and "resin" impregnate your own tool blanks. I've tried it and the results were OK. Not great mind you. Just OK. Back when I was turning pens this seemed like a good idea to make premium blanks out of punky wood.

You need a vacuum pump that can pull about 25" Hg. I have one and use it on my lathe as a vacuum chuck. Then you need a vacuum chamber. I used an old pickle jar. The test piece was some spalted silver maple that had the consitency of styrofoam. But the color was amazing! I used Minwax Wood hardener as the "resin" but other have actually used melted plexiglass (in acetone). I adapted the lid of the pickle jar with some fittings and made sure it sealed well. Then I got an old soup can, put a wire handle on it, and then filled it with the maple test piece and the wood hardener. As soon as you pull a vacuum, the test piece started to suck up the hardener. I maintained the vacuum for a couple hours and then allowed the piece to dry. After it dried I found that the hardener only penetrated about 1/8' to 1/4" into the wood. I was told that drilling a hole right up through the center of the test piece (as mist pen blanks have this anyway) would help. I never tried that but reasoned it would work.

After all this mess I shelved the vaccum rig and haven't touched it since. However, your idea of using it to make chisel handle blanks has peaked my interest. You could probably drill a small diameter "stopped" hole up the middle of the blank and that would allow the "resin" to infuse more of the blank.

[rob streeper]

Can you eyeball the depth of penetration into the wood from your test cuts?

Just asking, 'cos 25-30 mins is an awfully short time when it comes to vacuum work, however I haven't used Miniwax Wood Hardener, nor do I have any idea of the properties of mesquite in this situation; I mainly work with epoxy & Aussie HW where "overnight" is a more effective measure of time scale. :-


It is very hard to visualize. I cut through the area just behind the saw plate mounting region, smoothed off the surface and applied denatured alcohol to the clean surface. Based on the pattern of evaporation I can see that the penetration is roughly 4 mm from all surfaces exposed to the wood hardener solution. Since the region that clamps onto the blade is one of the more likely places for damage to occur during manufacture I think 15 min infusion will work fine. I made test cuts in various areas of the handle and the wood behaves much better under file and rasp with less tear outs and a very perceptible increase in hardness.

The Minwax product is an acetone solution. In infusing this test piece I cut the stock hardener back about 50% with acetone to decrease the viscosity.

Overall, I am very pleased and it now seems, pending a test of finish-ability, that the Minwax product will make mesquite much more useful for saw handles.

[Skew ChiDAMN!!]

It is very hard to visualize. I cut through the area just behind the saw plate mounting region, smoothed off the surface and applied denatured alcohol to the clean surface. Based on the pattern of evaporation I can see that the penetration is roughly 4 mm from all surfaces exposed to the wood hardener solution. Since the region that clamps onto the blade is one of the more likely places for damage to occur during manufacture I think 15 min infusion will work fine. I made test cuts in various areas of the handle and the wood behaves much better under file and rasp with less tear outs and a very perceptible increase in hardness.

4mm? That's a respectable depth, given the vacuum time.

I have given some thought in the past to doing short (as compared to "overnight" :rolleyes:) sessions, shaping down 'til "fresh" timber is exposed and then repeating the process, terminating in one final vacuum session once the timber is fully shaped.

Admittedly 'tis more labour intensive, but your input - & info I've gleaned elsewhere - suggests that it'd shave days off my current process, from start to finish. :think:


Overall, I am very pleased and it now seems, pending a test of finish-ability, that the Minwax product will make mesquite much more useful for saw handles.

That's the important thing; that you're happy with the results. I'll be keeping an eye on this thread to see how you feel about the finish-ability... from the browsing I've done on Miniwax Wood Hardener it appears that it's not water-proof & tends to turn milky (similar to shellac) if wetted. Which may - or may not - be a problem. Not a criticism of the product, just an observation and not really relevant to your original post.

Thank you for the feedback and here's to hoping your saw handle is a total success! :2tsup:

[rob streeper]

Hi Rob,

Thanks for posting that, I just realized that I have a vacuum tank and good vacuum pump sitting on the shelf.. my son used it when he was doing plastic molding.

I guess the time for complete penetration would depend on viscosity and how porous the timber is..

Ray

Hi Ray,

The bubbling largely stopped at 15 minutes. I tapped the container to get bubbles that adhered to the surface of the wood to detach them and closed off the pump valve after another few minutes. I could only draw about 22 in. Hg because of the acetone solvent. I have a vacuum leak valve in the top plate that allows me to slowly vent the chamber. I allowed the handle to sit for about 10 minutes under vacuum and then vented it.

Cheers,
Rob

[Ron Bontz]

Well, timely post indeed. About a year ago I looked into this process for some saw handles and turnings. Things got busy and the research was shelved. Last spring I got a close look at some chisel type handles Blue Spruce had infused. I liked the results and finally, about a month ago, got around to sending various wood samples off to be infused. Including fidddle back mahogany, sycamore, Tiger maple, etc. If I ever get this stuff back I will let you know the results. Take care, Ron

[BobL]

I would like to warn anyone making a vacuum chamber out of glass of the potential dangers.

If the glass breaks there is the danger of an implosion whereby the glass collapses onto itself and and then explodes outwards sending shards of glass at VERY high speed.
In laboratories that use glass vacuum chambers, this is treated as a very serious OHS risk.

It does not matter if one is really careful, sometimes all it needs is a gentle tap against the chamber or placing the chamber under vacuum onto an uneven surface so the glass experiences a slight stress.
The glass may also already have a microcrack in it and be a ticking time bomb in this regard. Repeated use of the chamber may also eventually generate such a crack leading to this effect.

Most of the time the glass will just crack and lose vacuum but it's not worth the risk of an implosion.

To mitigate against such an explosion a metal screen/cover placed over the top of the glass container before the vacuum is applied is a requirement in a laboratory.
The screen should also of course only ever be removed once the vacuum has been released.

A screen made of tough Al security mesh would be OK for small chambers, but for bigger chambers steel mesh should be used.

A solid steel chamber is the safest. If visual is required a piece of thick security glass (two layers of glass sandwiching a layer of flexible plastic, OR single layer layer of glass covered on both sides sides with quality security film) can be used in conjunction with a rubber seal. The thickness of the glass depends on the area of glass needed. As a guide a 100 x 100 mm viewing port should use at least 12 mm thick glass.

An no you cannot just cover a glass container with security film.
Most glass containers are too thin and too stressed to be secured in this way.

[DSEL74]

I would like to warn anyone making a vacuum chamber out of glass of the potential dangerous.

If the glass breaks there is the danger of an implosion whereby the glass collapses onto itself and and then explodes outwards sending shards of glass at VERY high speed.

It does not matter if one is really careful, sometimes all it needs is a gentle tap against the chamber or placing the chamber onto an uneven surface so the glass experiences a slight stress.
The glass may also already have a microcrack in it and be a ticking time bomb in this regard. Multiple uses of the chamber may also eventually weaken the glass leading to this effect.

Most of the time the glass will just crack and lose vacuum but it's not worth the risk of an implosion.

To mitigate against such an explosion a metal screen/cover placed over the top of the glass container before the vacuum is applied is a worthwhile safety procedure.
The screen should also only be removed once the vacuum has been released.

A screen made of tough Al security mesh would be OK for small chambers, but for bigger chambers steel mesh should be used.

A solid steel chamber is the safest. If visual is required a piece of thick security glass (two layers of glass sandwiching and layer of flexible plastic, OR single layer layer of glass covered on both sides sides with security film) can be used in conjunction with a rubber seal. The thickness of the glass depends on the area of glass needed. As a guide a 100 x 100 mm viewing port should use at least 12 mm thick glass.

An no you cannot just cover a glass container with security film.
Most glass containers are too thin and too stressed to be secured in this way.


What about the polycarbonate or acrylic containers??

[BobL]

What about the polycarbonate or acrylic containers??

Yep - safer but not fool proof.
They can also be used more safely as viewports for steel chambers.
Small chambers should be made from a minimum of 12 mm thick acrylic and large chambers of 1" thick.
PC can be thinner but I don't know how much thinner.

Thick material is used to ensure very high vacuums and for safety reasons.
However, there is not much difference in the safety implications of 24" or 29.9" of mercury.
Even a vacuum of 20" of mercury can cause an implosion.

Some info and ideas here
Acrylic Vacuum Chambers from Terra Universal (http://www.terrauniversal.com/environmental-chambers/acrylic-vacuum-chambers.php)
Vacuum Chamber - Full-view Acrylic (http://www.abbess.com/vacuum/vacuum-clearview)
Plenty of ideas on youtube - not all of them are safe in my book.
This one looks OK.
How to make a homemade vacuum chamber for degassing silicone - YouTube (http://www.youtube.com/watch?v=LTHAL0udCyA)

NB long term Acrylic must also be kept away from UV and daylight.

[rob streeper]

What about the polycarbonate or acrylic containers??

Polycarbonate and acrylic are fine for water based products but don't use them with the Minwax product or any other product that is dissolved in acetone. That's why I made my top out of Delrin - it's essentially acetone proof.

As to the implosion hazard, I know the risks very well as I have a lot of high vacuum work experience, where do you think my fancy fittings come from? No matter what, when working with low or high pressure chambers always use a face shield and safety glasses together.

[BobL]

As to the implosion hazard, I know the risks very well as I have a lot of high vacuum work experience, where do you think my fancy fittings come from? No matter what, when working with low or high pressure chambers always use a face shield and safety glasses together.

If so then why you didn't mention the risks and mitigation thereof in your OP.

Then if you know something about OHS best practice, engineered solutions like a steel chamber or at least a mesh screen are generally superior to PPE like a face shield. A face shield should protect eyes/face but what happens to the rest of the newbie that decides to pick up a glass chamber under vacuum and the chamber decides to let go while they are holding it?

The risks are low but the potential damage can be high.

[RayG]

Here's the one my son used on his plastic stuff.

It's about 8" diameter and made from a length of heavy wall PVC pipe, the base and top are 1/2" thick perspex. So I guess acetone solvents are out.. :)

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The vacuum pump is a nice looking portable RobinAir, the type used by refrigeration mechanics.

There are two fittings, one connects to the vacuum pump and the other to a valve to release the vacuum when you want to open it

Ray

[rob streeper]

If so then why you didn't mention the risks and mitigation thereof in your OP.

Then if you know something about OHS best practice, engineered solutions like a steel chamber or at least a mesh screen are generally superior to PPE like a face shield. A face shield should protect eyes/face but what happens to the rest of the newbie that decides to pick up a glass chamber under vacuum and the chamber decides to let go while they are holding it?

The risks are low but the potential damage can be high.

Bob,

Sorry for leaving out the safety stuff. For me most safety considerations go under common sense. OHS best practice is not my field I am involved in laboratory safety and a variety of vacuum operations associated therewith.

To All:

Other considerations on the vacuum chamber issue:
1) Keep the chamber size as small as practicable, less to implode means less stuff flying around if it fails.
2) Don't use thin wall glass containers like pickle, mason or jelly jars. Soda lime glass used in commonly encountered containers is too fragile for this kind of work. Containers made from it typically are not designed to contain pressure or vacuum. Drawing vacuum on one of these is very dangerous.
3) If possible use Pyrex or another high strength laboratory type glass - don't use tempered glass at all. Glass vacuum dessicators are availble on Ebay and if undamaged, see 6 below, are an ideal tool for this work if you are careful. Something like: Glass Desiccator Vacuum Jar Lab Dessicator Dryer 6" New | eBay (http://www.ebay.com/itm/Glass-desiccator-vacuum-jar-lab-dessicator-dryer-6-New-/380778655904?pt=LH_DefaultDomain_0&hash=item58a82d30a0)
4) Check the chemical compatibility of all chamber materials including the chamber itself, fittings, pump and vacuum tubing.
5) Use vacuum tubing, not garden hose, latex tubing or any other expedient. Tygon vacuum tubing will save a lot of hassles in the long run.
6) If using glass be certain that it is not damaged in any way, even seemingly tiny scratches can be crack initiation points. So no scratches or chips of any kind can be tolerated.
7) Use containment as Bob counsels. A rudimentary expedient is to wrap outside of the chamber in fiber reinforced strapping tape. Ugly and it will give the safety inspector heart palpitations but it is better than nothing.
8) When under vacuum do not pick the chamber up or otherwise move it. You are already too close and by moving it around under vacuum you are inviting an accident.
9) No matter what, always use a face shield and safety glasses together. Do not take them off until the chamber is fully vented to atmospheric pressure or until you are on the other side of a wall or other substantial barrier.
10) All of this being said, I am in no way providing you life or limb preserving guidance and accept no responsibility for the comments posted here or anywhere else on the Internet. If you choose to mess around with electricity, sharp things, machines, welders, torches, vacuum or pressure chambers, chemicals or any other Darwinian selector out there you do so at your own risk.

Cheers,
Rob

[BobL]

Some good safety tips there Rob. :2tsup:

If only common sense was a common as we'd like it to be even on this forum but we just need to look at you tube to see how relatively rare it is.

[rob streeper]

Some good safety tips there Rob. :2tsup:

If only common sense was a common as we'd like it to be even on this forum but we just need to look at you tube to see how relatively rare it is.

Hi Bob,

I don't know how the legal situation Re: tort liability is in Australia but here in the US the giving of safety advice can be a liability. For instance, if somebody follows my path on this vacuum work and gets hurt they could potentially sue me and recover because I was not explicit and totally complete in my warnings. Thus, in my posts, where I am almost always doing hazardous stuff, one should not take instruction. By making these posts I am simply documenting what I have done and lived to tell the tale. Your results may, and almost certainly will, vary. I have specialist knowledge of these things that keep me safer. If you are not a specialist you should not try to replicate what I am doing and if you do you do so at your own risk.
In other words: If you try this you may die or be seriously injured - I disclaim any and all responsibility for your actions.

Cheers,
Rob

[BobL]

Hi Bob,

I don't know how the legal situation Re: tort liability is in Australia but here in the US the giving of safety advice can be a liability. . . . .

Fortunately we are not quite as litigious as the US (although unfortunately we are headed this way).
In Australia we are probably more likely to be sued for not providing any advice, than for providing some advice.
The advice I received from OHS lawyers/consultants about litigation risk where I used to work was to provide and implement "best practice advice" - not perfect but least litigiously risky than anything else.

The forum owners make it abundantly clear that all advice on these forums is of a general nature and users should seek expert advice outside these forums.
In some threads (especially those involving electrical work) you will see big bold insertions of posts about this by the mods.

I like to think knowledgable folk who post useful information on these forums will include appropriate safety advice.

[Robson Valley]

There are some process points:

1. Consider the vacuum that you have to pull to get this done. Unless you're on top of an oil diffusion pump or a turbomolecular pump, you won't ever see much better than 10^-3 Torr, even with a top of the line rotary vacuum pump. My experience with infiltrating and embedding wood specimens suggests that several pulls and very, very slow air inlet will allow the air pressure to push the infiltrate further into the wood. Common vacuum pumps might give you 1(?)mmHg which is no screamin' Hello unless you have big bucks for a real pump.

2. Consider the anatomy of the wood itself: not all wood cells are open to the environment, not like an open cell sponge. Thus, two things: first, it will take some time for air molecules to find a path from inside the dry wood cells to the environment. . . . it takes time. You can stop pumping, hold the vacuum then pump again. Second, the infiltrate is made of far larger molecules and it will take much longer for these things to find a path into the wood. You can't hammer them in. 1 atm pressure is what you work with.

I spent several years researching the failures in grafting success with apple trees. Don't believe that I made any more than 2,000 microscope slides of embedded apple wood specimens. Histological wax is huge when compared with air. Epoxies would be similar. Given the time, most specimens would be adequately infiltrated (5mm) in less than a week. Block sizes were about surgar-cube in dimension.

The plastic bucket chamber is least likely to shatter. Any deformation due to ambient outside atmospheric pressure should make it leak like a sieve. We stored electron microscope film over phosphorus pentoxide in a glass vacuum-dessicator. The biggest mess was the dang vacuum grease on the rim to try to get the things to seal.

[rob streeper]

For those of you who have been following this story I decided to perform a test-to-destruction on the resin infused but already broken mesquite saw handle today. I repeatedly dropped the handle from waist height on concrete with no damage. I then did multiple drops with my arm extended overhead with the same result. Finally I tossed the handle in the air. It achieved about 15' altitude and broke on impact. Here is the result. The impact was directly into the lower horn and it sheared off the bottom section of the handle. Overall I rate this method as producing a handle that is pretty tough. It's also easy, relatively quick and inexpensive.

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[planemaker]

For those of you who have been following this story I decided to perform a test-to-destruction on the resin infused but already broken mesquite saw handle today. I repeatedly dropped the handle from waist height on concrete with no damage. I then did multiple drops with my arm extended overhead with the same result. Finally I tossed the handle in the air. It achieved about 15' altitude and broke on impact. Here is the result. The impact was directly into the lower horn and it sheared off the bottom section of the handle. Overall I rate this method as producing a handle that is pretty tough. It's also easy, relatively quick and inexpensive.

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Interesting Rob. From examining the fractured pieces of handle were you able to better determine the depth of penetration after using the vacuum impregnation process. Was this depth more or less than your initial expectations. How much of the outer skin hardening on the handle are you likely to then lose after later sanding prior to applying the top coat finish.

Stewie;

[Robson Valley]

Thanks for the experiments, Rob. You can walk the walk.
I wonder how that handle would have performed in service, on a saw.
Do you imagine that you could have yanked and twisted on it until failure?

[BobL]

Interesting Rob. From examining the fractured pieces of handle were you able to better determine the depth of penetration after using the vacuum impregnation process. Was this depth more or less than your initial expectations. How much of the outer skin hardening on the handle are you likely to then lose after later sanding prior to applying the top coat finish.

Stewie;

These would indeed be very interesting to know.

With a porous material containing some moisture and maybe other volatiles, improved penetration may be achieved by repeated shorter pumping down sequences rather than than one long sequence.
By this I mean pump down and then expose back to air, repeat this 4-5-6 times and then perform the infusion.
The reason for this is that the back and forth pumping may better open up the pores and enable more "stuff" to infuse.
A weight check would enable this to be demonstrated

[planemaker]

These would indeed be very interesting to know.

With a porous material containing some moisture and maybe other volatiles, improved penetration may be achieved by repeated shorter pumping down sequences rather than than one long sequence.
By this I mean pump down and then expose back to air, repeat this 4-5-6 times and then perform the infusion.
The reason for this is that the back and forth pumping may better open up the pores and enable more "stuff" to infuse.
A weight check would enable this to be demonstrated

Hi Bob. The other issue that may cause some difficulties for Rob is that the Mesquite being used is also diseased wood. I would imagine very similar to what we call spalting. That being the case the pores of the wood may already be beyond expanding to there previous healthy wood size, preventing a good intake of infused resin. It would also be worth mentioning that this type of treatment would only work on certain open pored wood types. I am also unsure how this infusion would work on a lot of our Australian oily timbers. I also note that this infusion process is commonly used for pen making, where the center is hollow bored prior to this resin infusion. This step would most likely enhance greater penetration as a % of the timbers overall thickness. Not a possible option to consider with saw handles. I should include I have no previous experience with wood infusion.

Stewie;

[rob streeper]

I put the fractured handle under reflected illumination using a 480 nm UV 200 mW light, held the amber safety glasses over the lens of my iPhone and took some snaps. The limit of infusion is difficult to see in the photo but I measure about 3mm depth of penetration perpendicular to the grain and 8-9mm penetration along the grain.

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Here is an edited image indicating the approximate penetration that I can see by eye under UV illumination.

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[rob streeper]

Hi Bob. The other issue that may cause some difficulties for Rob is that the Mesquite being used is also diseased wood. I would imagine very similar to what we call spalting. That being the case the pores of the wood may already be beyond expanding to there previous healthy wood size, preventing a good intake of infused resin. It would also be worth mentioning that this type of treatment would only work on certain open pored wood types. I am also unsure how this infusion would work on a lot of our Australian oily timbers. I also note that this infusion process is commonly used for pen making, where the center is hollow bored prior to this resin infusion. This step would most likely enhance greater penetration as a % of the timbers overall thickness. Not a possible option to consider with saw handles. I should include I have no previous experience with wood infusion.

Stewie;

This particular chunk of wood is quite sound. Mesquite tends to fracture along the grain following the annual growth rings. The heart wood is very resistant to fungus and is mostly subject to attack by ants. The sapwood is very liable to decay and on older logs the sap wood essentially falls off of the aged timbers. Mesquite also is very abrasive and tends to eat bandsaw blades, even TC tipped.

[rob streeper]

Thanks for the experiments, Rob. You can walk the walk.
I wonder how that handle would have performed in service, on a saw.
Do you imagine that you could have yanked and twisted on it until failure?

I did your test. I clamped the remaining chunk of handle in the vise as shown. First I tried to twist it. I could hear cracking but could not break it one-handed, I estimate approximately 100lb force applied. I had to tighten the vise mid-way because the handle started slipping.

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Then I flexed it from down to up. I estimate about 150lb lifting force applied. It broke at the weakest point. I rate it 'really tough'.

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[rob streeper]

Here are some shots of the test handle with finish. I sanded up through 280g, wiped on some BLO, applied shellac and wax and buffed. Looks better in person. The end shot shows that the Minwax wood hardener treatment did not affect the finishability of this wood under these conditions. Overall I am extremely pleased with the result.

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[rob streeper]

To check up on how much material I am getting into the handles I did a little measurement experiment today. Between three handle blanks I managed to infuse a total of 190 gm of polymer solution. I cut the stock solution back about 30% with acetone.
The label states that the VOC content is 275 g/l. The stock solution from the can has a density of 1.08 g/ml or a liter is 1080 gm. If we assume that the solvent is pure acetone, having a density of 275 gm/l / 0.79gm/ml gives us 348 ml of acetone per liter of hardener. Thus, in 1 l of stock solution 275 gm is acetone and 805 gm is solid, presumably polymer. The volume of this solid material is 1000 - 275/0.79 or 651 ml. The bulk density of the solid is therefore 725/651 or 1.23 gm/ml. The polymer is thus possibly polymethylmethacrylate (~1.18 gm/ml) but more likely it is polycarbonate (~1.20-1.22 gm/ml).
My 30% cut reduced the percentage by weight of polymer in the infusion solution to ~51%. Thus, I managed to get 190 gm x 0.51 or about 97 gm of polymer into the three handles or roughly 30 gm into each one. So the earlier comment was close to correct, dissolve Lexan, not Plexiglas, in acetone.
They're hanging up to dry overnight now. I'll report on their characteristics tomorrow.

[rob streeper]

To check up on how much material I am getting into the handles I did a little measurement experiment today. Between three handle blanks I managed to infuse a total of 190 gm of polymer solution. I cut the stock solution back about 30% with acetone.
The label states that the VOC content is 275 g/l. The stock solution from the can has a density of 1.08 g/ml or a liter is 1080 gm. If we assume that the solvent is pure acetone, having a density of 275 gm/l / 0.79gm/ml gives us 348 ml of acetone per liter of hardener. Thus, in 1 l of stock solution 275 gm is acetone and 805 gm is solid, presumably polymer. The volume of this solid material is 1000 - 275/0.79 or 651 ml. The bulk density of the solid is therefore 725/651 or 1.23 gm/ml. The polymer is thus possibly polymethylmethacrylate (~1.18 gm/ml) but more likely it is polycarbonate (~1.20-1.22 gm/ml).
My 30% cut reduced the percentage by weight of polymer in the infusion solution to ~51%. Thus, I managed to get 190 gm x 0.51 or about 97 gm of polymer into the three handles or roughly 30 gm into each one. So the earlier comment was close to correct, dissolve Lexan, not Plexiglas, in acetone.
They're hanging up to dry overnight now. I'll report on their characteristics tomorrow.

I paid $7.49/can on Amazon for 8 cans of Minwax hardener, or $15.81/l.

Polycarbonate pellets are $50 for 18 lb (8.16 kg) with free ship on Ebay, $6.12/kg. Polycarbonate Plastic Pellets 18 lbs Jupilon Ships Free | eBay (http://www.ebay.com/itm/POLYCARBONATE-PLASTIC-PELLETS-18-lbs-JUPILON-SHIPS-FREE-/330570575293?pt=LH_DefaultDomain_0&hash=item4cf78aadbd)

The stock hardener is 805 gm/l polycarbonate so to make a liter I need .805 kg/l X $6.12 or $4.93 worth of PC.

Acetone is $19.96 at Home Depot, with tax = $21.60/gallon or $5.70/l. To make a liter of hardener I need 0.348 X $5.70 or $1.98 worth of acetone.

Total cost / liter thus is $6.91. 1 l is 2.11 pints thus the per pint cost to make it myself becomes $3.27.

Home Depot charges $11.86 tax included for a pint. $8.59 for a can? Lesson learned.

BTW, I just ordered some PC pellets and will make my own from here on out.

[Robson Valley]

From your experiments, I would conclude that the wood had been stabilized well enough for the service requirement.
Given the nature of typical handsaw actions, the process seems durable.

Anybody else have experimental results to contribute?

[rob streeper]

From your experiments, I would conclude that the wood had been stabilized well enough for the service requirement.
Given the nature of typical handsaw actions, the process seems durable.

Anybody else have experimental results to contribute?

We'll see. Tomorrow I test one of the three to destruction.