I am getting an American elm log given to me soon. I want to saw some table tops from it. I am taking the thing to save a buddy from having to haul it off (no-one can split it for firewood) It is 60"across, the main reason I want it is because it so funky shaped, I can see wonderfull cross section slabs for table tops. I have flat sawed and dried elm before and had more than normal problems with cracks running up the lumber with the grain (some went 6" on thin stock). Any advice would be a big help, I know there are better species for this, but this tree has character. With the deep furrows and lobes by the time I sawed it to cant I would waste most of it trying to saw it for lumber. I am going to saw cross section slabs, just need some help on how to keep it together.
You can almost guarantee it will crack somewhere, so maybe plan where you want it to crack, and then make a sawcut (straight in a radial path, or crooked to match the 'funky' shape or like a jig-saw puzzle from the bark to the pith center) that will open up as they dry. If you place the crack as you want it, then a random crack from drying is less likely. Even then, you may get some short ones around the section.
Sometimes some relief can come from sawing the slab at an angle across the log, to get an oblong slab. Some of the drying stresses are relieved that way, but elm would be a tough one even at that.
Another way is to rob a pie shaped piece from an adjacent disc (slab) and carefully inlet it into the slab that has checked, trying to match up the growth rings (done after a long time drying).
I've seen little currugated pieces of metal pounded into he end of a log to help prevent this, not sure how big they were though.
Daren,
That's going to be a tough one.............Elm is beautiful and it's well worth the effort. I would try some green wood sealer. I get mine from Woodcaft. If you can't do that try melting parafin wax and coating it very liberaly with that. It will slow down the drying process. If it does crack, like Beenthere said you can inlay or I use clear porable epoxy to fill the cracks and then you can throw stuff in there to make it look like you meant for that to happen. Inlace granules work good. They come in all sorts of colors. I also use turquoise or quartz just something to detract from the crack.
Good luck and as always make sure you give us something to look at when you get going on it 8) 8) 8)
I was thinking Tung Oil to slow it down ? The tree is sort of a freak, I don't know how to describe it, but it has 10 big limbs all coming out within 2 feet of each other and pointing up like a basket. I am going to try to got some cross sections were the limb grain and pith is coming into the center of the butt log. I hope to have a bunch of little circles inside of the slab. Know what I am saying?
Actually the multibranch slice like that may have a better chance of drying relatively intact than a complete ring. You are likely to get localised star cracking in each knot, and maybe some between them, but the slab as a whole has a better chance of staying intact.
Like the others suggest, coat it with wax of some description and then think about filling the cracks later
Cheers
Ian
I've seen folks cut a bowtie section out of an area they knew would crack and hammer in a piece of ebony or walnut. I was told it stops the cracks and looks good.
With Elm, you need high tech help for sure :
Pentacryl or PEG (Polyethylene Glycol)
Soaking for a couple of weeks in PEG (Polyethylene Glycol) would help tremendously.
Pentacryl would be more expensive, but would give superior results.
Personal sources? Sorry, no, but these two chemicals provide amazing results.
Search engines showed several sources. Here are a couple:
Pentacryl:
http://www.preservation-solutions.com/pentacryl.php?pssessionid=e3881a4a47171e359c1098a8d9bc70e7
Polyethylene Glycol:
http://www.rockler.com/product.cfm?page=686&cookietest=1
Phil L.
I guess I need to do some reading on PEG, I have used 100's of gallons of it over the years in boilers and chillers. I have never seen any with out color (pink, yellow, blue). I am sure that is added in the stuff I am familiar with. It's going to take a kids swimming pool to soak it. At least it won't freeze left outside. ;), hope my barn cat doesn't get thirsty.
Daren
Read up, as ethylene glycol is not polyethylene glycol (PEG).
At the molecular weight (1000) that works best for stabilizing wood, PEG-1000 is a solid. It is not as solid as candle wax or paraffin, but close. More like lard (for those who remember lard) or butter at 40°. This PEG-1000 needs to be melted and mixed with water (50% by weight) and then the wood submersed in the solution. Best if the solution is kept warm (130-140°) while the wood is soaking. Something to keep the wood submersed that is not steel (ferrous) as it reacts with the solution and will turn the wood black. Borax is added to the solution because it will want to feed bacteria and form mold on top as the piece soaks for as long as it takes for the solution to penetrate the wood cell walls (that is the big unknown in this scenario, as there is no way to tell before final drying if the PEG is in the wood bulking the cell walls so they cannot shrink thus preventing cracks).
Various outfits sell PEG, but few sell PEG-1000. They like to either sell a lower molecular PEG like 400 as it will stay in solution and therefore is easier to work with. Or they want to shave PEG-3000 (which is more solid and more like paraffin wax) and sell it 'shaved'. However the higher molecular weight is much tougher to get into the wood cell walls and extends the treating time to 'light years' instead of ½ years. Once PEG is in the wood, it being hygroscopic, it will tend to move out of the wood in times of high humidity (lower molecular PEG worse than higher, and is why 1000 was settled on as a happy medium to use).
I don't mean for this to be discouraging, but only informative so you can make a decision to move ahead being better informed.
Chemical companies at one time would only sell PEG in bulk (55 gal drums) which had to be melted and repackaged for reasonable use. However, these companies decided they didn't want to sell less than a box car full of 55 gal drums, or a semi load at a time. Knocked the interest down in a hurry. I haven't followed the PEG treating of wood closely for the last 10 years, but don't think it is done so much anymore. The pentacryl treatment is a new one on me, and I have some doubts about how good it is (seems like a close extension of the PEG treatment, but I really do not know). I did talk to a wood stabilizing expert (IMO) who has done extensive research into stabilizing wood and he had never heard of 'pentacryl', which really surprised me.
If you can find a copy of "Treating Green Wood With PEG" by Patrick Spielman (Taunton Press, I think), you will get the best printed information available on the subject.
You can make a temporary soak tank the exact size you need with a wood frame and heavy (construction) plastic sheet.
Beenthere did a good job of covering everything else.
:P BeenThere is right on with his info.
The Bruce Hoadley textbook, Understanding Wood is also a good source on
the use of Polyethylene Glycol. Its absorption and effectiveness are tremendously
temperature dependent. A warm solution penetrates much more quickly.
Since this form of glycol is not poisonous (in great contrast to ethylene glycol or anti-freeze),
a simple way to treat a large item might be to dig out a shallow depression in your readily
available sawdust pile, line it with a few layers of polyethylene protected by cardboard,
then submerge the item and forget it for a while.
Fine Woodworking Magazine is also an excellent source on the use of both these products.
When I have checked with industrial suppliers about PEG in the 1000 molecular weight,
they seem mystified, but have no trouble locating the other less useful grades. After all,
I don't need it for its laxative value or as a prep for a colonoscopy;
:D :D I NEED IT FOR WOOD!
Phil L.
Daren,
Was this America Elm dead on the stump by any chance? I just milled a very large one like that into boards and it was very well behaved for elm. I saved some 20" wide boards from the cant and they were pretty flat out of the kiln. :) It had been dead for many years so it was dryer than usual. If yours was dead, you may have an easier time with it than you think.
cleqaux, it is part dead , that is why they are removing it but it looks sound. As far as the PEG goes, I am not a chemist. I did do some reading and now understand the difference between the liquid I am familiar with and the gel form that PEG is at in the higher molecular number. Same molecules, just arranged different. I have access to just about any chemical I would ever want, that part is a long story (wife works for a Fortune 100 processing plant, best friend is a chemical engineer for a Forture 500 company...) In my reading the things that disturbed me are the facts that the PEG is hard to finish over and it weeps for a long time after the treatment. I will not rule it out on a smaller piece in the future, a turned bowl or something, but I think I will keep stewing for this one. He is not going to cut it right away, and it will keep this winter till I decide.
Daren, If you have a place to store the log I would do that for a year or two. Sure it will be tougher to cut but it will be more stable.
The 56" DIB American Elm I got from my Grandparents land was dead standing for several years. I felled the tree, sealed the ends and then over a year later I cut the lumber. WOW. STABLE, FLAT, and BEUTIFUL!
I still have about 800 bf left and I am saving if for special projects.
You could send some out here for crating the corn planter. :D Then you would be guaranteed of getting it returned, maybe. ::)
Come on Frank, you know it would never make it back here :D
Yeah but think how sexy the corn planter would look surrounded by all that beautiful wood! Reid