Seems the only way to save my tree ring is to soak it in peg. 36" across makes for a large vat. Question. Can a plastic container be used with peg, or will it be dissolved?
People report both ways on finishing a piece of wood preserved in this way; it will and will not take a finish. I want to get a clear finish on it. Will I be able to?
I use plastic. In your circumstance, you could certainly enclose in a large plastic bag, add solution, use a straw to extract excess air.
PEG is a slimy, waxlike substance which will leave your piece darker, deliquescent, and almost completely resistant to any finish. Are you SURE this is what you're after?
deliquescent 1. To melt away. 2. To disappear as if by melting.
Not sure I understand how that describes the results of soaking the ring in PEG.
Dave
This ring is over 100 years old. I want to finish it and mark significant dates on it ... a conversation piece. Any ideas?
I wonder if I could just cut a 30 deg wedge out and 'release' the stress in that way... keep it from cracking all over.
I would say let it crack, as that is what it will do eventually. You can try soaks in liquid dishwashing detergent denatured alcohol, (research on rec woodturning), and then drying. These methods will not cause problems with finishes. Steaming and boiling can also be done, but I haven't tried either yet. You could try some sort of huge band clamp around the slab, and that might work. Wood moves, and rounds will crack. robo hippy
Get another dictionary, where you'll discover the meaning:
Absorb moisture, to dissolve gradually by absorbing moisture from the air.
Cutting a single kerf from outside to center would be my choice. Low angle plane will reveal the growth rings. You can always Nakashima it if you decide to use it as a display.
Don't take anything out, it'll find comfort along the place you relieved the stress.
Layer either side with double layer newsprint, change one a day for a week, once a week for a month, and once a month until the whole thing stops losing weight.
NB - neither method "works" at all.
the unbroken circle, while contracting, will find a weak spot to create some space. Banding would do nothing, since it stresses in the direction the wood wants to go anyway.
I'd suggest googling (or asking) over at rec.woodturning. Bowls are often turned "green" and placed in a plastic bag. The bag is then opened occasionally for a while to let out the moisture, and resealed. Thus slowing down the drying process. It would seem your situation is similiar to seasoning a giant turning. This has worked well for my small turnings, but someone at the other group might know more about how to handle a large piece better. --dave
Doesn't work for disks. Bowls survive because the "rings" are effectively hollow and they can collapse inwards. There's some warping, which is why you only rough turn them thickly when green, then finish turn once dry after they've finished warping.
I'd make a couple of disks (or more, if I had them) then put a radial sawcut into the centre. This puts all the "crack" into one place, rather than allowing them to occur randomly, and probably multiply. When they're dry, pick the best matching pair, convert them to opposed half-disks and stick them together.
A big ring is usually stabilized by putting an iron band around it. You could adopt that principle, or you could simply let it split.
Plastic should work fine to contain the PEG. I have never used PEG, but have a book "Woodworking Factbook" by Donald G. Coleman, 1966 which describes the process of finishing with polyurethane. This is fairly old but he said polyurethane was the only finish know to dry properly on PEG treated wood.
Given that the thing is already doing its best to shrink anyway, what use is compressing it going to have?
Disks don't crack because they shrink, they crack because because tangential shrinkage is bigger than radial shrinkage (as has been posted in great detail many times before). The outer rings no longer fit around the inner rings. Avoiding cracking thus needs to either stop shrinkage (PEG), to remove the centre and allow the rings to collapse in on themselves (bowls), to allow the rings to stretch (halving) or possibly to crush the centre of the log to a smaller diameter (small disks, or stored energy for later sudden splits).
If you could invent an iron ring that compresses the centre preferentially to the outside, then it might work.
You're right so far, but you're missing something. When you compress the disk, you compress all the layers radially -- that is, you add radial shrinkage without adding more tangential shrinkage. This brings things back in proportion, thereby stopping the cracking.
An alternate way of thinking about it is that you're moving the outer rings in, by squeezing things. Thus, they end up in a circle with a smaller circumference, and thus they don't need to crack in order to fit. There's no need to "invent an iron ring that compresses the centre preferentially to the outside", as you suggest, because compressing the outside doesn't hurt anything.
- Brooks
Deliquescence describes the property of dissolving through the absorption of moisture in the air. Some chemicals exhibit this property (I think anhydrous NaOH might be one.) Polyethylene glycol is one, as well (I just checked.)
Since his workpiece will not lose form, but will absorb moisture, it would suffice to say it's going to be wet. You might get away with "hygroscopic".
er
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.