Stabilizing wood

[C_Claycomb]

A word of warning regarding thin material. It can have tendencies to warp when you do the cure. I had some curly Californian Redwood treated some years ago, the pieces cut 3/4" thick warped along their length. Had to take off about 1/8th thickness on a handle length. I also had trouble with a big slab not getting full penetration. I am told that this is due to Redwood having resin, although when cutting and working it is nothing like pine, no smell, no sticky saw dust.

The next batch I had done, for drying, I turned to my microwave. Having stored the pieces on top of the boiler for a week (they had already been dried in doors for some years as slabs, I then subjected them to short radiation blasts until they stopped expelling steam. After all the air drying I was surprised by just how much steam came out with the microwaves. I think I hit them for 20 seconds at a time.

It is good to have this info here, as you have no doubt seen, not many people here are doing their own stabilisation. A buddy of mine has the gear, although I don't know what his results have been. He too bought the Cactus Juice from the US. Have you searched around on places like BladeForums and Knifenetworks? If you have questions the folk there may have already discussed it and are certainly more likely to have the experience to help you than folk here, sadly.

Regarding bubbling, I wouldn't think it has to do with the cells, but the structure they form. Denser wood is likely going to have smaller pores and so be more reluctant to let all its air out in a rush.

Good luck! I am sure everyone will be keen to see results

 

[C_Claycomb]

I have a few scales I would like to vacuum chamber but I am having trouble finding liquids made for this anyone have a list of them that could be used?
I used to be able to get a wood hardener at the paint stores but none carry it any more I assume due to such a small call for it now it was used to harden up rotting wood in heritage buildings here...

As I mention above, the best place for finding information is going to be the US knife sites, with US pen turning being another group to look to. Wood hardener isn't a good fluid for treating handles, really, and not comparable in quality of result compared to the methacrylate monomers that are the standard. Wood hardener tends to be solvent based, with a high solvent content to carry the compound into the wood, but when the solvent evaporates there isn't much solid material left behind. Sure, its enough to make punky rotten wood (that had the consistency of a sponge) hard, but its effect on even soft hardwoods like birch is minimal. Not enough to stop them absorbing water and moving freely.

 

[gonzo_the_great]

I must admit, I've only used solvent based resin, for vac impregnating.
But From what I've seen (on good old YT), suggests that overnight soak in CJ, after releasing the vac, is about right.

 

[Janne]

When I released the vac, it was fascinating how quickly the level dropped. Had to top up. Overnight it went down further.
I will leave them until tonight, then drip dry ( to salvage as much resin as I can) and cook in the toaster oven.

All wood looks darker, more beautiful.

I know of several knife making fora, but prefer to stay on one, this one. Might (maybe) be of interest to people here. And I tap into the knowledge and skills of you guys!

 

[Robson Valley]

That's a good sign that you lost a lot of CJ volume with the incoming air pressure.
Tells me that your evacuation was quite successful.

Possibly useful to have a working knowledge of wood anatomy. They are all different, as different as fingerprints.
Redwood (Sequoia) has vastly different resin ducts when compared with pines and the great variation within that group.
Western Red Cedar and Yellow Cedar are quit aromatic to carve. Tomorrow, you can't smell a thing.

Perfusing wood with epoxy (araldite) was a daily routine in the lab that I studied in for years.
The greater variety in the anatomical details is among the hardwoods. Almost abstract art, some of them.
Times and temperatures varied wit the wood species.

Otherwise, an oven baked oil finish does not make the knife scale wood greasy. The oil is inside the wood.
You can't wash it out, even with boiling water. A few minutes and you are done forever.

 

[Janne]

Cooking now!

 

[C_Claycomb]

Not sure about Cactus Juice, but all the wood I have had professionally treated by WSSI or K&G came back to me smelling of chemicals, and with the resin still less than rock hard. Full hardness and loss of smell took some time after that. Not sure how long I am afraid. I just stuck all the stuff in a box and left it for several months before trying to work it (again). Might have been that it only took a week or two, but I think it was longer. Wood in question was that Redwood, quilted maple and birch burr.

Might not apply to you, but if it does, don't panic, give it some time to finish curing. All mine did and it was worth the wait.

 

[Janne]

I baked the chunks at around 210 F for around 2-2.5 hours last night. Let cool overnight and unwrapped them this morning.
The resin is nice and hard. The only two pieces that look like not much resin has penetrated are the Palm tree wood and Seagrape.

Still feels fairly light. Weird, those two were the 'bubbly' ones! Maybe the cell structure is not for a quick release of air ( hence the slow bubbling) and slow absorbtion.\?

I need to send samples of raw untreated wood to Robson V to have a look on!

 

[Stew]

I know of several knife making fora, but prefer to stay on one, this one. Might (maybe) be of interest to people here. And I tap into the knowledge and skills of you guys!

You should add some pictures of your set-up as well.

 

[Janne]

If you knew my computer skills you would not write that. I got back into Photobucket, posted 2 photos and the b-rds started to ask for a pound of flesh!

They still have all my pictures, including the ones of my watch collection.

I am not a member of any photo hosting site.

Very simple setup. Vacuum pump, pressure hose - 3 way connector with on/off valves , hose, three way connector with gauge, pressure hose and jar.

The jar is a Chinese made cookie jar with a badly fitting tin lid.

 

[Bazzworx]

What level of vacuum is required to stabilise wood? I work in the vacuum industry and we sometimes scrap various types of pumps that still work but don't provide the correct level of vacuum for their application and are too expensive to repair.

 

[Janne]

Mine gauge went down close to 30 something.

 

[Bazzworx]

Oh ok so I guess that's inches of mercury. Its not a unit I'm very familiar with but I think -29.92 inHG is absolute vacuum. So basically the more vacuum the better to out-gas the wood.

 

[Robson Valley]

Bazzworx: The vacuum needed is often done solely on the basis of observation of the aspiration process.

The concept is to drop the pressure to get the wood air to expand enough to see bubbles if not foaming.
Very slowly allowing the air pressure to rebuild pushes the perfusing liquid into the wood.
The wood anatomy resists rapid penetration, even if the process takes a day or two to accomplish.
If 1 atm = 760 Torr, I'm guessing that .5 - .3 atm is enough.

You can get 3-4mm spinach leaf disks to sink in aqueous bicarbonate but 3-5 cycles might be needed.
Students were using hand pumps over 125ml heavy erlenmyer flasks.

 

[Janne]

I am on the sea level, I think that influences the level of vacuum?

Well, 2 feet about the sea. During Hurricane Ivan I would have been 3 feet under the sea level......

 

[Robson Valley]

That's good enough for sea-level, including the tides! 1 atm = 14.7 psi. = 760mm Hg = 760 Torr.
You can use the very same scale at any altitude just that you won't be starting from 760mm = 1 atm
at your location.

The valley bottom here is about 750m, if my memory serves.
Peaks around my house are no more than approx. 2,700m (9,000').

Hope I got the numbers right. Like a fool, I gave away a pretty good rotary pump
originally used for exactly this: aspiration and perfusion of tissue samples.
I don't play with all my tools and toys as it is so should not bemoan the loss of the pump.

 

[Bazzworx]

Thanks Robson that's really interesting!! I might have to have a go at it.

 

[Robson Valley]

Well, try it. If you can cobble some kit together, do some experiments.
The tricky part, if there is one, is to build the vacuum containment vessel
with a window so you can watch.

Cactus Juice is a trade name for a thermosetting polymer and it is not cheap.
Do your messing about with something else like fiberglas resin.
Anything with a viscosity well above plain water.

Get it down to a routine and I predict the equipment will pay for itself and more.

 

[Janne]

The vacuum chamber, tubing, valves and stuff were the cheap part.
We have limited selection of stuff here on island compared to UK, US or Canada, but still plenty.
The jar cost me about USD 20, third one tested did not implode.

 

[Janne]

I let the bits after set, then ground off the seeped out hardened resin.
Quite a bit of colour change on all wood types.
Darker.
Had to use a respirator as the dust is extremely fine, like a cloud around me and the machine.

Have started to drill the holes for the tangs. Huge difference in feel when drilling. Harder, but smoother.