Stabilizing Recipe

I

itrade

Joined
Jul 3, 2002
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645
OK I've finally tried it myself. I thought I'd pass on exactly what I used and the results.

Mixture
1 lb Toluene (yes weight not volume)
1/4 lb Paraloid B72 solids (http://woodfinishingsupplies.com/Conservation.htm $10 a pound)
This produces a 20%wt solution.


Stuff

Very cured birds eye maple 1/4"ish thick
Deer Antler


Process

Place Toluene and B72 in quart Mason jar.
Put the lid on and shake for 1 hour to dissolve the B72
Submerge wood and Antler in jar (leave 1/2" air space!)
Use the Magic Vac mason jar deally and suck the air out.
It will bubble
Re-suck
Bubble more
Reapply vacuum every 10 minutes for 3 hours (it took this long for the bubbles to slow to almost nothing.)
Leave sealed for 27 hours
Remove and dry (dries hard in something like an hour - amazing)

Results
Excellent.
It appears to completely penetrate both materials.
It added a bit of golden hue to the wood and a little grey to the antler.
It polishes up as nice as the commercial stuff.
However, exposure to water raises a grain. Tells me the wood isn't fully saturated. It will need a final coat of finish to seal. Antler appears fully sealed.


Other notes:

A larger air volume in the jar (or a secondary jar) wouldn't require so much re-sucking.

Couldn't tell you about other woods.

Couldn't tell you about longevity and yellowing, however, B72 is used by museums for priceless artworks.

Acetone is another solvent folks use, but I've read you get better penetration with Toluene.

Higher % of B72 might benefit, but it might reduce penetration. 20% gave impressive results, but not complete for wood. I'm going to try some 40% tests. Both as a second treatment and as a single treatment.

Cheaper and easier than other wood finishing products: $10 of B72 and $10 for a gallon of toluene makes alot of mixture and the wood didn't absorb much.

27 hours isn't magic, that's just when I got home from work. Less might be OK. More wouldn't be needed.

All in all 20% gave very good results. I consider the wood stabilized even if not completely sealed. I'm very pleased.

Steve

PS I'm just passing this on, because it was hard for me to find exact information.
 
Thanks for the information. I find it very helpful. I like how detailed your directions are. I intend to do some stabilizing experiments with Resinol 90C as soon as I get it and plan to post my results once I think I have it figured out. Tom Lewis
 
You're welcome Tom.

I'm really, really interested in your results so please don't waste any time posting them.

The wood in 20% solution really didn't develop that hard as nails finish you get from knife and gun. The antler is wonderful. Hopefully I can try the 40% solution real soon and we can compare to the Resinol.

Steve
 
Can I interject a question?

Is there any difference in penetration between end grain and side grain in your results?

Dan
 
Good question Dan - I was wondering the same thing.

The effect was pretty consistent throughout. There was a harder 'shell' on the surface. Once that sanded away it was consistent.

That makes me hopeful that I can use a higher % and get a harder result.

Hope that helps. I wonder if the experienced B72 users could chime in.

Steve
 
If it's making a harder shell on the surface, how deep does that go? If it's at least 1/8" it might make sense to do 90% of the shaping before stabilizing.

Which brings me to my next question = how much shaping do you guys do? (before stabilizing)
 
Dan,

The 'shell' is just like a varnish coating. That part isn't really in the wood at all. The wood (my sample was 1/4" looked the same thru and thru. Which is good. I can put curves the edges and things and not have to worry about changes in color or texture. But with this batch I'll need to seal it with something - probably super glue.

The commercial stuff I've used is the same all the way thru too. It's just much harder.

That's what I'm hoping to get with the 30 or 40% mix.

Does that help?

Steve
 
Using a higher boiling solvent like toluene would seem to make sense when a vacuum is used. I've mentioned this before, but a lot of people don't seem to believe me, so I'll bring this up again--

skip to next post if bored.:)

Under static vacuum, any volatile substance will evaporate, and try to fill the vacuum. The higher boiling the substance the less the vacuum is decreased. Of course, the lower the temperature, the less the substance will evaporate also. This is consequence of a property called vapor pressure. More volatile substances exert a higher vapor pressure. The temperature at which a substance exerts a vapor pressure equal to atmopheric pressure is the temperature at which it boils.

That means in closed, evacuated jar at constant temperature the lowest vacuum that can be maintained without continually pumping off the solvent faster than evaporation is fixed. The higher the boiling point of the solvent, the higher the vacuum that can be maintained.


1 atmosphere = 760 mm mecury.

example:

Acetone boils at about 56 deg C at atmospheric pressure. (132 deg F)
At about 39.5 deg C (103 deg F), the vapor pressure of acetone is 400mm.
At 7.7 deg C (45 deg F) the vapor pressure is 100 mm

This means that no matter how many times the jar is evauated, the lowest pressure that the jar will achieve is still over 1/2 an atmosphere--At about 100 deg F. Cool down to 45 deg F and the lowest pressure is about 1/7 atm. Of course, there will be a slight cooling because of the acetone evaporation. Only when all of the volatile acetone is gone (pumped out) will a significantly higher vacuum be achievable at a given temperature.

Toluene boils at about 110 deg C at atmospheric pressure. (about 230 deg F)
At 31.8 deg C (about 89 deg F) the vapor pressure of toluene is 40 mm (about 1/19 atm.)
At 6.4 deg C (about 43 deg F) the vapor pressure of toluene is 10 mm. (about 1/75 atm)

Quite a difference. Clearly, equipment to get maximum vacuum with acetone can be a lot less sophisticate than equipment to get the most out of toluene.

Some solvent will probably be trapped inside the wood when a rapid-hardening sealer is used. This may prevent the stabilizer from reaching full hardness and cause problems later if the handle is heated above the boiling point of the solvent.

Note that toluene's boiling point is higher than that of water.

I would think that some stress testing to simulate say, being left in a hot car might be a good idea. Say, leaving some stabilized material in an electric oven at 120 deg F for a day or two.

Has anyone tried a solvent that is normally applied to wood like turpentine or citrus oil (limonene?)

I've not tried to stabilize any wood myself--for what little I've done, I've just used tung oil. So feel free to tell me I'm full of crap on the effects or use of vacuum for stabilizing.

But don't try and argue with the vapor pressures;)
 
Steve, leave it cure longer after pulling from solution and the grain may not rise when wetted.

RL
 
firkin

That's great information, thanks. Very helpful, actually. I'll stick with the Toluene. Probably also going to try some tests under pressure. Any idea what the effects are on penetration might with only 125PSI?

RL,

Yeah I took another piece that had cured another 24 hours and same effect. Can't wait to try another run, but don't know how long it will take to dissolve a 30% solution! Next time I'll buy the pre-dissolved stuff.

Steve
 
Be careful with Toluene. It is a flammable liquid that is a dangerous fire risk. It produces explosive concentrations in air between 1.27 and 7%. It is also toxic by ingestion, inhalation and skin absorption with a TLV in air of 100 ppm. If you work with it in these volumes handle it outside and away from any souces of ignition where the fumes can disperse. Also, make sure that you wear nitrile gloves and not latex if handling.

While still dangerous, acetone is far less risky than toluene. It too is flammable, but produces explosive concentrations in air between 2.6 and 12.8%. It is only moderately toxic and is narcotic in high concentrations. It has a TLV of 750 ppm in air.
 
Good points hso.

Just because something is higher boiling doesn't mean that it's necessarily less likely to form a toxic or explosive vapor/air mixture.

Solvent toxicity is another reason to wonder what happens to the solvent that soaks deep into the handle when a hard shell cures on the outside.

(Maybe citrus oil/citrus solvent (limonene) deserves a look because of that? Wouldn't drink it, but it is generally accepted to be among the safest solvents.)

Another difference is that acetone will dissolve in water in any proportion--only a tiny bit of toluene will dissolve in water.

Acetone fire is like alcohol fire
toluene fire is like oil/gasoline fire.

Relatives of acetone exist with higher boiling points. Methyl ethyl ketone (MEK) is commonly used.
It boils at about 80 deg C (176 deg F).


RE using pressure--

Maybe looking up pressure-treated lumber would help to see what would happen to the wood? Don't really know how to compare the two processes.

About safety--
two words: BLAST SHIELD.

Protect yourself against broken equipment and accompanying spray and/or aerosol/foam of chemicals. Remember what happens if you shake up a beer and break, puncture, or simply open the container. Use a container intended for pressure. Inside such a container, you can put a glass liner, but some liquid may foam out of the liner when pressure is released.

(I posted a quite a bit here before on potential hazards with pressure, should be in the archives...
Won't take up space with it again:))

An evacuated glass container can implode, and once past the center, the pieces can fly out like an explosion. Criss-crossed duct-tape leaving little windows isn't a bad idea to keep the pieces of a jar together if you're achieving decent vacuum. A metal screen enclosure or a bucket with a lid works too, and will catch liquid. Do not evacuate or pressurize a glass container that is scratched. Tapping or striking the walls of an evacuated glass container is a bad idea.

Remember the docs will have a tough time finding bits of glass embedded in some part of you.

Have fun.
 
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