understanding stabilization

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JRay8

JRay8

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Arnold, MD
so when i purchase stabilized blanks from psi like the dyed boxelder how are these made. i have read up on the worthless wood but i feel like these are two differnt things entirely. if i read correctly the worthless wood you are just filling the voids in the wood. the stabilized blanks i have purchased the resin and dye go all the way through the wood so how does the process differ?
 
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Jim,

I was doing some research on this just last week. When using PR with worthless wood, you are using it to fill the gaps in the wood and make it usable (my simple interpretation). Stabilizing takes a piece of wood that you would otherwise not be able to turn because it is not "stable" enough and fills it with a hardener using a vacuum chamber. I am not endorsing Curtis' vaccum chamber, but I learned a lot about the process while I was reading up on his vacuum chamber on his website (http://www.turntex.com/index.php?pa...egory_id=144&option=com_virtuemart&Itemid=121).

Hope this helps!
Kevin
 
I saw Curtis's demo on stabilization at our meeting last weekend. Very interesting process. It is used to make soft, punky wood solid enough to turn. When you put the wood under vacuum with the stabilizing resin in the chamber, it forces the air out of the wood fibers. After leaving it under vacuum for 30 minutes to an hour, when you release the vacuum, it draws the stabilizing resin into the wood and once dried, it makes it solid enought to turn. That is why when stabilized with dye, it is dyed through out the block of wood. The dyed resin is drawn all the way into the wood blank. You can actually see the resin level drop as it is drawn into the wood replacing the air that was forced out under vacuum. Very cool to watch.
 
They are two different processes. When I make 'worthless wood' blanks, I use PR and pressure. The pressure gets rid of bubbles and forces the PR into cracks in the wood. When stabilizing, you use a special stabilizing solution and vacuum. The vacuum draws the air out of the wood. This air space gets replaced with the thin stabilizing solution. The blanks are then 'cooked' to cause the stabilizing solution to set up.
 
looking at that sexy spanish oak burl and oceans pen i wonder... why stabilize the wood first before casting? What effect did the stabilazation have in this case?
 
JRay8 said:
looking at that sexy spanish oak burl and oceans pen i wonder... why stabilize the wood first before casting? What effect did the stabilazation have in this case?
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The resin used in the worthless wood process doesn't enter the wood. Unstabilized wood would still be 'unstable' after casting.
 
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Have a vacuum chamber but haven't used it yet. The question I have is this -- does the stabilization fill any voids? What I mean is I have wood that has very fine cracks (max of 1/16") mostly from shake or from around knots. The wood is not punky, it is solid. Is this a candidate for stabilization or does it need casting, or both? Hope that makes sense.

Jeff in northern Wisconsin
 
ttpenman said:
Have a vacuum chamber but haven't used it yet. The question I have is this -- does the stabilization fill any voids? What I mean is I have wood that has very fine cracks (max of 1/16") mostly from shake or from around knots. The wood is not punky, it is solid. Is this a candidate for stabilization or does it need casting, or both? Hope that makes sense.

Jeff in northern Wisconsin
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Stabilization will fill the voids to an extent. To what extent I do not know for sure, but this is a good question for Curtis. What the stabilization process does not fill, the casting process should fill it unless the void has been filled and prevents the casting medium from entering it.

The denser the material the less effective the stabilization will be. Stabilization is better for softer porous materials such as something like Spanish Oak burl or Buckeye burl for example. Hard maple is not really a good candidate for stabilization, but spalted maple would be.

Dave
 
Stabilizing will fill some very small crack to varying degrees. I have had some that filled completely and some that still had some voids in it. Really hard to say for sure. Depends on the wood and the size of the crack.
 
Wood is like a bale of hay. It is hollow fibers. Now if you take out a big chunk of the bale of hay, somehow it needs to be replaced. Pouring resin will fill the void.Depending on the resin, it will also penetrate some of the hollow fibers too, which gives you better adhesion of the resin, but the resin will not penetrate the fibers all the way through, rather just the surface fibers. Stabilizing is trying to fill all the fibers, replacing the air with plastic. The idea is to suck out all the air from inside the wood, which allows the stabilizer plastic to seep in. The stabilizing plastic is thin to fit in the fibers, so it's going to also fill some cracks but not if they are huge. The stronger the vacuum you can produce, the more stabilizer you can get deeper into the wood. If you add a dye to the stabilizer, that will also color the wood at the same time. Obviously, the thicker the wood, the more power/vacuum you need to penetrate all the way through.
 
Close Jeff --- but the amount of vacuum you can draw is limited to having nothing to pump out of the chamber. Where pressure compresses gas, vacuum just empties space. Having more horsepower on a pump allows some marginal improvement in capture of those few stray atoms and compounds -- but 29 inches of mercury about as good as it gets at sealevel (14.8 psi equivalent pressure on the outside of the container). When there is something in the chamber what will "boil" - the pump will keep pulling the gas phase out until there is not much left. The more that goes to vapor phase, the longer it takes.
 
To answer Jray's question, why stabilize wood before casting. If you stabilize the wood, the resin fills the pores in the wood. When you cast it, no air or minimal air comes out of the stabilized wood, if a lot of air comes out of wood as the resin cures, there will be tiny air bubbles in the resin right at the surface of the wood. This causes weak bonding of the resin to the wood and makes it much more likely the blank will come apart on you while being turned.

_____________________

Steve
Novelpens.com
 
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