Drying a slice of Maple tree

[tncruzin]

   I need some help guys.  I recently cut down a large Maple tree from my yard and am interested in drying a cross-section of the trunk to build a table.  I've learned that this is one of the most dificult things to do.  It's 4-5" thick with a diameter of about 30". I'm a green horn on the subject and would appreciate anything information anyone can provide. I'm hoping someone here can give me step by step directions on what to do.

[Weekend_Sawyer]

 I have been using Pentacryl latley on a wild cherry cut across grain about 1" thick. I cut 2 of them, treated one with Pentacryl and left the other one alone. Brought both of them in the house. My house is a bit too dry, about 35% rh.

The untreated one split within 2 days, the treated one is still looking good after about 2 weeks.

I used the search engine on this page to learn more about Pentacryl and then did a network search on it and found it at woodshop.com.

It is not cheep at just under $15 a quart.

Let us know how it comes out.

[Oregon_Rob]

It sounds like an interesting project, I would also be interested in knowing how to, too!

[beenthere]

tncruzin
If you have already sliced it off, then it is drying as we speak. PEG (polyethylene glycol) -1000 has been used effectively on some species (unfortunately not well on maple as penetration is difficult). Also, because you have already cut this one off, likely too much surface drying and checking has already occurred.
The use of PEG is somewhat over-rated, but with experimentation it can work for the intended purpose of keeping the wood from checking. The experimentation means that a one time treatment of a single item is very difficult to get right the first time. Walnut is one of the easier species to treat, and maple one of the more difficult ones, along with cherry.
PEG treatment works only on green material (the higher the moisture content the better). PEG-1000 (molecular weight of 1000) is a wax-ike chemical that is mixed with water in a 50:50 solution by volume, and the wood item is submerged in the solution for "as long as it takes" the solution to exchange with the water in the cell walls of the wood to a depth of 1-2". There is no way to know when the PEG solution has reached that depth without experimentation on a lot of "alike" pieces, all other conditions remaining the same. The way PEG works is it gets into the cell walls of the wood and will not allow the cell walls to shrink when the wood dries, keeping the wood cells in their green size - thus no shrinking, no checking.
IF the wood eventually is treated enough to stop any of the surface cells from shrinking, the PEG is hygroscopic and will bleed out of the wood over time from changes in humidity. So, applying a finish that will either restrict the bleeding (some epoxy's have been able to do this) or one that will allow the PEG to bleed through (an oil finish) and then it can be wiped off.
PEG is a very safe chemical, and at lower molecular weights is used in hand cremes and the like.
My recommendation would be to prepare it (good drawing by Jeff a week ago on the 19th under Gen.For., Sawmills&Milling, The biggest Tree in England...) with a "planned" crack routed or sawn to relieve the cross section and allow it to shrink normally.
Hope this helps. I don't have experience with Pentacryl, so cannot comment on it. Some techniques try to encapsulate the wood in "plastic" or epoxy, which will prolong the checking. Problem is that water vapor will escape through most coatings, paraffin wax being the best coating for restricting the movement of water vapor.

[Swing_blade_Andy]

Beenthere

Its amazing wot you know - where do you get this info.

Good for me because its difficult to get a conversaiton with anyone who really knows the science. I'm trying the find the scientists and even they don't seem to really know. Its a 'knowhow' technology I guess.

There has been some terrific work done in Sweden on the 'Vasa Ship' which is a 13th century Warship. I am pretty sure that they used PEG on it but after 20 years its leeched out and there is a curious build up of sulphuric oxide which will reek havoc. Naturally they are looking for more solutions.

I'll start doing experiments I think to get this one right. It sounds like it needs to be done. Do you know if the 'bath' of PEG/water is heated will it penetrate deeper /faster wot not?

Andrew

[Fla._Deadheader]

Just a guess here. Would it do any good to "band" the piece, so that, as it dries, the band could be tightened enough to keep up with the shrinkage??? On the old growth Cypress that I am messing with, it doesn't check as bad as it cups?? There is a LOT of stress. I am cross cutting stumps.

[Tom]

I don't think banding something like that would help Harold.  You would never keep up with pressure and it would split one night in your sleep. On the other hand, Cypress stumps cross-cut like the one you show are pretty forgiving.  If you don't cook it in the sun there is a good chance it will make  it on it's own.

[beenthere]

Swing_blade_Andy
Years ago I helped a couple guys treat a lot of wood with PEG. Frustrating times, but sometimes the results were truly amazing and rewarding - as I said -sometimes.  There is a very good book titled "Working Green Wood with PEG" by Patrick Spielman, Spielman Woodworks, Fish Creek, WI. I don't know if Patrick is still there, but he is an excellent writer and used good information for this book. I searched for it and see that there are copies available, including used copies.
Heating PEG does assist the penetration into the wood but the solution supports the growth of mold, so a bit of Borax in the solution will hold off the mold. I recall that one must avoid all steel in the solution, such as steel weights to hold the wood down, and use of a steel tub. Plastic or fiberglass seems to be the best for a container.
The best description I have found of the Pentacryl and its use as a wood treatment reminds me a lot of PEG. Some minor differences and different claims, but few of the claims are any different from what the PEG treaters (sellers) would claim, so I'm not sure just how different it is. I couldn't find an MSDS (material safety data sheet) for Pentacryl, so am at a dead end there. I doubt the two chemicals are the same.  PEG-1000 is a solid at room temperature and must be heated to get it into a liquid so it can be mixed with equal weight of water (I think that is right, and not equal volume of water). PEG of molecular weight less than 1000 is sometimes sold to treat wood, but it isn't a good idea, as this low-molecular weight PEG bleeds out of the wood over time.

[Don P]

Here's a chunk of wood I've had around a few years that I like cause it shows just what Harold is describing. Its an end cutoff from a 6x6 treated post that has dried. It shrank without checking because its so thin but it shows dramatically the stresses involved in drying. The tangential direction shrinks almost twice as much as the radial direction. Since this piece was thin it could go into the third dimension rather than checking. Imagine what would happen if you were to push down and flatten the piece, it would open up a check. Thats what a bigger piece or log has to do. The stone tile has a straight edge, notice the flat sides of the timber become convex.

I haven't got experience trying to dry cookies but I believe the Pentacryl is advertised as an acrylic monomer. I just bought some clear epoxy casting resin, wonder if thinning something like that and vacuum bagging it would do any good?

[Fla._Deadheader]

Excellent example, Don. I been messing with letting some slices get kinda dry, and they do just what you show. THEN, I soaked them with water and weighted them down. So far, they are FLAT. ?? We'll see how long they stay flat. I am giving plenty of time to let them dry.

[Tom]

Harold,
I've played around with thin stock and was concerned about the moisture getting out from under the weights.  I put a single layer of paper towel under and over the piece to allow the water a means of "wicking" out.  It seemed to work ok but I don't know if it was necessary.

[Larry]

I have cut a lot of fish boards and clock faces at angles from 30 to 45 degrees across the log and never had a problem with cracking.  It got me to thinking at what angle the cracking would start - 60 degrees - 75 degrees?  Might be something to think about or explore.
Larry

[Minnesota_boy]

fFound a nice description of what Pentacryl is and how to use it.

http://www.woodnshop.com/PENTACRYL.htm

[burlman]

Here is an experiment for you to try. A few years ago I was working at a woodworking show, I met an old fellow who told me his trick for drying discs for clock faces, and axe handles that won't shrink out of their heads, was to soak the wood in Prestone, or car anti-freeze. I was curious of course, always  trying new things for my rustic furniture projects.  I recently cut some large Manitba Maple(box elder) discs, as well as some great root burls. That was April, I used pure anti-freeze on them, brushed it on liberally every time they looked like they were dry. They were stickered and left in my  shed over the summer. The temperature was often over 90 degrees in there. I must of treated them a dozen times till about the start of August, then just let them be. I brought them into the workshop before Christmas, the moisture meter read all 8 pieces at around 12%. All pieces were 3 inches thick. I just planed down a future table top , a triple crotch  disc , lovely pink and cream color with the pattern of the three stems coming tgogether. the best part, not even a hair line crack to  be seen. This maple I have tried before with poor results, lots of shake, and the normal checking problems. I have used the  anti-freeze on all fresh cut burls, and other one of a kind pieces that  i hope will keep. Now that were into our deep freeze here in Canada,  I can't really gage how any of the  pieces are doing. If you try this, I think that if you can submerge the disc in some sort of pan, or tray, so the hardwood will have time to soak in would be better. I  havn't yet tried a hardwood disc as you are attempting. So far positive results in Butternut, pine, and cedar discs, all 2in. or so thick. And it seems to help so far on hardwood burls, but they do take along time to season anyway. well good luck let me know your results, at burlman@canoemail.com

[Tom]

Welcome Burlman.  Don't run off.

I think that chemically, anti-freeze and PEG are the same thing its just the molecular configuration  that causes one to be thicker or heavier or whatever than the other.  I've heard of anti-freeze being used to stabilize wood and also heard that it will leach out pretty quickly relative to the PEG formulas.  

That stuff is also poison.  I've heard of people putting it out to kill stray animals.  It's supposed to be a horrible way to die and I wouldn't do it to Dog or Man.  Putting it on stock that may be turned into eating containers might be  little iffy.

[Don P]

This is a good read on that subject, some of the borate solutions we were discussing earlier use propylene glycol as a non toxic carrier. I put up a search and found it at about $10/gal. Will look next time I'm at the auto parts, but I think its the non-tox antifreeze available now.

http://www.atsdr.cdc.gov/tfacts96.html

[beenthere]

Just to keep us on the right comparisons here, PEG is polyethylene glycol, and not propylene glycol.
Maybe some similarities in name, but I don't believe PEG is at all toxic (any more than water) according to MSDS (data sheets). Now one could probably be pumped full of the PEG stuff and become dead (which may disprove the "toxic" bit ), but within reason it is apparently safe, as PEG is allowed as a chemical in many hand creme's and lotions applied to the skin. (Now, please don't mis-understand me, I am not promoting PEG).  
I have also heard of anti-freeze being used to treat green wood to keep it from checking. Can't confirm any success over any long period of time however.
Not too many years ago a fellow in eastern TN claimed to have a method (system?) to treat wood and keep it from checking. He claimed he could not patent his method as it was too easy and too simple, and would just be stolen from him. So he was after someone (govt?) to pay him a few million to reveal the "simple" procedure and the public could have his information. Several attempts were made to convince people the expenditure (to him) would be worth it to have a method to dry wood without drying checks (along with numerous other claims), but to my knowledge, no money exchanged hands and no secret process, method, procedure, or whatever was revealed.

[Jason_WI]

Beenthere,

There is a Robert P. Speilman, Fish Creek in the Door County phone book. I would assum this is the same person you refered to. I live 10 miles from Fish Creek in Egg Harbor. Tourist trap capitol of world, especially for all those Chicago tourists. Locals call'em FIB's.

Jason

[DouginUtah]

Not too many years ago a fellow in eastern TN claimed to have a method (system?) to treat wood and keep it from checking.

Sounds like you are talking about Eugene Sexton's ESP-90 process. Here is his web page:

http://www.esp90.com/

A lot of other descriptive pages here:

http://www.esp90.com/page1.html/docs/

-Doug

[Don P]

The PEG is bulking the cell wall. I've heard several times about ethylene glycol and PG helping with drying. It is too thin to be bulking anything but does change the way things dry. I'm just guessing that they modify how the wood dries. Lower the gradient within the piece, the wood dries more uniformly, and so lowers the drying stresses, less checking?

[beenthere]

Jason_WI  I am not sure if that is Patrick. I think there is a Spielman Wood Works, or something akin to that name, in Fish Creek that is connected to Patrick. Beyond that, I don't know.

DouginUtah, Don P.
Both are correct IMO. Thanks for the ESP_90 link.