Preventing the dreaded CRACK (properly drying of a crosscut disk)
I recently took down a large red oak near my house…about 36″ diameter at base. Four logs are going on the LT40 for boards. There was a 4′ butt log that was to short for boards so I am going to cut it laterally and make round end tables to display the growth rings.
One of the arborists stated that they had done something similar and to use multiple applications of Butcher’s Wax to displace the water and prevent cracking.
Question. Has anyone else done this or something similar to prevent cracking along the rays? I don’t want a table full of corrugated nails or bow ties (although this could be an interesting look).
Will this displace the water? Apply to one side so the moisture is forced out the back? Apply to both sides simultaneously so the water is forced out the sides?
Also, by applying this much wax ,will this change the look of the red oak?
thanks for the advice in advance!!
Replies
Logs of most species ( I'm familiar mainly with Northwestern US woods) will shrink mostly in circumference and less so from the outside of the log to the center. I would say the best way to guard against a round splitting from the outside toward the center is to make a relief cut, a planned split if you will, from the outside toward the center. A proven method of controlling splitting in working with logs is to make a relief cut from the outside to center running the length of the log them simply place the log with the cut facing away from view. The part that you see will be prone to less splitting.
Bret
Cracking
Ace
When I was in school there were a few guys who had some success with a product called P.E.G. They would soak a fresh cut cross section in the P.E.G. and the material would displace the free and molecular water on the cells. The slice could then be worked without worry of splitting. I'm not sure what the practical size limits are if any. I think the stuff can be purchased fromLee Valley
cracking round
OK I've bought the P.E.G. How do I know how long to cover the round? It's redwood, about 15" x 15" and 3 inches thick.
I've been keeping it damp. Does anyone know how to use the P.E.G.?
thanks for any advice,
ggherron
As was mentioned, use PEG.. Polyethelyne Glycol. (I might have spelled that correctly.) I used to use this waxy like material on full rounds that I later turned on the lathe. There was an article in FWW way way back on the process and the material. A well known turner, Ed Moulthrop, used it on very large apple wood rounds.
Other than using PEG, I can't imagine any way to prevent discs from splitting as they dry out. Wood shrinks more tangent to the growth rings than radially (perpendicular to the growth rings) and that unbalanced shrinkage will sooner or later produce one or more splits. Perhaps the arborist watched his waxed disk for a short period of time. Wax will show drying and hence delay the eventual crack. "Understanding Wood" by R. Bruce Hoadley explains this phenomenon in depth.
PEG works...
http://www.vasamuseet.se/InEnglish/about.aspx
In the early 1960's the Swedes found a warship that was sunk in the Stockholm harbor on it's maiden voyage in the 1600's. They raised it up, built a museum around it and sprayed PEG on the entire ship, every 20 minutes for about 10 years, to make sure it displaced all the water. The museum (and the preserved ship) are incredible. You can see a small sampling of it at the link above, but the point is, PEG works very well at displacing water in wood.
Enjoy, Mike
it only works well on fresh green wood
ron
fresh green wood
Ron,
Since most of us are highly unlikely to find 350 year old oak at the bottom of the harbor, I'll have to agree. The ship was pretty darn wet when they started.
Mike
http://www.preservation-solutions.com/faq-pentacryl.php
PEG is old school. Pentacryl is new school. Haven't tried it myself but have heard that folks have done cross sections of wood successfully. The properties of pentacryl are so much better than PEG as well.
I used to be in school a long time ago. I guess this simply makes me old. So tell me (slowly) what makes Pentacryl "new school." And if PEG is "old school" what's wrong with it?
By the way, new or old, that Pentacryl stuff is $pendy stuff. I used to keep a 5 gal bucket of PEG.
PEG is a waxy substance that can replace the water in wood, but remains waxy and can come back out. Pentacryl appears to be an acryllic monomer that can soak into the wood like PEG, but it differs in what happens next. Within the wood it can polymerize (cure) to form a hard material that strengthens the wood and will not leach out.
Acryilic-impregnated wood has been around for a long time too, but I think that it used to be done with heat and pressure so it was not a do it yourself procedure. Pentacryl might be an improved version that's more convenient, but it seems from the FAQ that a lot less acryllic gets into the wood, so it will not be as dense or strong as the other sort that is sometimes used for durable tool handles.
Related Query - can the crack be fixed?
I have a lovely pear cross cut my uncle carefully preserved and gave his mother. When she died I asked for and got it. Had it on a bay window and it developed a crack! Oh dear. Is there anything I can do to fix this? I'm guessing not, but thought I'd ask while you all are talking about PEG ad penarcyl... whatever.
THanks
results?
What did you end up doing? What type of results did you get? I have a similar piece of wood that I am going to be making something out of.
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