PEG Solution

[Wyatt Holm]

Has anyone used this? What was the reason, and how was your success?

 

[Bill Boehme]

When I first started turning I heard about it on various Internet forums -- it was a big fad for a very short period. I bought two "wheels" of PEG 1000 from Craft Supplies (they no longer sell it -- it came in what looked sort of like the big cheese wheels and had to be dissolved in hot water). The stuff is sort of like a soft wax at room temperature. PEG (polyethylene glycol) comes in various molecular weights from about 200 up to about 20,000. The 200 mw PEG is a thin watery liquid at room temperature and PEG 20000 is like a very hard plastic. PEG 1000 was thought to be a suitable mw for stabilizing wood. Various molecular weights of PEG can be found in an extremely wide variety of products from soft drinks to cosmetics to floor waxes to the stuff you drink before having a colonoscopy. It is completely inert and due to the size of the molecules, it can't pass through the intestinal wall into the bloodstream.

I should mention that PEG is not something that is used to dry wood as many seem to believe. It can only be used on very freshly cut green wood (preferably, open pored wood) and its purpose is to try to stabilize the wood by replacing the bound water (and, by necessary extension, much of the free water) in order to stop it from warping and cracking. There are still a few die-hard proponents of PEG, but most woodturners feel that it is far more trouble than it is worth and has a few characteristics that make it less than desirable. Here are some of the issues that I have heard about:

• hygroscopic -- in high humidity areas, it can sometimes make the wood feel wet
• The stuff is stable which is both good and bad. The bad part is that it never dries, so some woods always feel waxy and tend to ooze a bit of the stuff onto whatever surface it is sitting on.
• Hardly any finish is compatible with PEG.
• It darkens the wood and gives it a look like it was soaked in used motor oil. The wood also tends to get more drab looking as time goes by.
• It doesn't save you any time in going from raw wood to finished product -- it only stabilizes the wood against future movement.

Other than that, I hear it is really great stuff.

What did I do with my two "wheels" of PEG? I still have them. I am looking for a suitable way to get rid of this white elephant, but so far I have not come up with any firm plans. I am considering sending it to our senior moderator/administrator here on the AAW forum as a token of appreciation for all of the hard work that he has done over the years, but I am afraid that he will see through that sham right off the bat.

 

[MichaelMouse]

Has anyone used this? What was the reason, and how was your success?

The Moulthrops used it with fantastic success, but I found it had all the drawbacks indicated.

It doesn't "replace" the water in the wood, it is a bulking agent which keeps the cell walls expanded. Since it has to be there, and is slick and hygroscopic, I use it for mallets. Soak up a bunch of pith-centered hop-hornbeam or hard maple mallets, and you have something durable, heavy, and "soft blow" wet to help your elbow. Great stuff there.

 

[Bill Boehme]

..... It doesn't "replace" the water in the wood, it is a bulking agent which keeps the cell walls expanded.

I shouldn't have used the word "replace" since it implies "displace" as in what the "alkies" sometimes imply about using DNA. My intended meaning is that it will be still there after the water is gone. But anyway, as I mentioned, it doesn't do anything to hurry up the process.

 

[MichaelMouse]

Takes the same amount of time for air at the same relative humidity to soak up the water from a PEG-treated piece as a non treated. So you simply add the treatment time to the head of the line.

Of course, if you're using PEG, it really doesn't matter if the piece is wet, it's going nowhere, and it'll never be truly dry.

I had reasonable luck with microwaved overdry PEG pieces by flash-drying the surface with acetone. You could get the old phenolic Watco to stick afterward.