# Propylene Glycol



## djg

Maybe my understanding of this subject is all wrong, so feel free to correct me.  PEG, (Poly Ethylene Glycol) is used to slow(?) down the drying process by replacing the water with PEG in the wood structure, thus preventing/minimizing cracking. I don't know if this is done under vacuum as done in the "Wood Stablization, etc" section of this forum, or if it's simply 'basted' on the all surfaces. If my understsanding is right, then can the monomer of a related glycol be substituted? I thought maybe placing the wood in a tub and covering it with PE for a while.


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## Schroedc

djg said:


> Maybe my understanding of this subject is all wrong, so feel free to correct me. PEG, (Poly Ethylene Glycol) is used to slow(?) down the drying process by replacing the water with PEG in the wood structure, thus preventing/minimizing cracking. I don't know if this is done under vacuum as done in the "Wood Stablization, etc" section of this forum, or if it's simply 'basted' on the all surfaces. If my understsanding is right, then can the monomer of a related glycol be substituted? I thought maybe placing the wood in a tub and covering it with PE for a while.



Here's a good article from Oregon State with quite a bit of detail and the do's and don'ts, According to the article there are some specific properties needed that aren't in the other compounds so substitution is not recommended.......

http://owic.oregonstate.edu/sites/default/files/pubs/peg.pdf

Reactions: Like 2


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## djg

Thanks for the article. I've saved it and will study it after work.


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## Kevin

Not saying it isn't worth a damn but PEG isn't worth a damn IMO. I used it extensively beginning in 04 and continued to experiment with it into 05 and for the price in my book Anchorseal 2 works as good if not better in minimizing defects during drying, and AS doesn't make the wood sticky througout like PEG does (if you get it to even penetrate in the first place). Granted AS won't help with punky wood but neither does PEG even though some laim it does - that was never my experience. 

Pentacryl isn't much better IMO even though the company that makes it claims that pentacryl will penetrate in 1 day whereas PEG takes 6 months. Pentacryl is also formulated to minimize shrinkage during drying thus in theory minimizes drying defects.

My experience with both of them has been less than sterling and for the money I wouldn't use either one again. I still have some of each from the last order if you want to play with it - have no idea what the shelf life is.

Reactions: Informative 3


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## barry richardson

A gallery here recently did a Moulthrop family exhibit. They are a famous bowl turning clan, that commands very high $$$ for their pieces, they are in the Smithsonian and all the big galleries. Anyhow, The description of their process said they treated their bowls with PEG, but I also saw the attached article that says they had a problem with PEG and the epoxy finish they use, it is a pretty technical article... if ya really want to go deep with PEG
http://cool.conservation-us.org/coolaic/sg/wag/2006/pine_06.pdf


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## Graybeard

Interesting article Barry. Seems that PEG was used before Anchor Seal was around. Just guessing, anyone know?
Graybeard


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## Kevin

Barry I believe that was one of the many articles I read about it before I first started using it. It's a good article but it did not help my results. Maybe I was expecting too much.


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## Alan Sweet

I don't if my 2 cents matters here, but..

With bowls, which I have rough turned wet, I soak over night in DNA. Air dry for a an hour or so, then wrap in butcher paper and put on shelf to slow dry for a couple days. Then I finish turning. I get very little cracking, I have had some. Very little distortion, but I have had some.

Water content after I take them off shelf is lower than 12%. More often lower than 10%.

Most of the bowls I have turned are 10" or less in diameter and I normally rough turn to 1/2-5/8 inches wall thickness. Maybe more.

Reactions: Informative 1


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## norman vandyke

Schroedc said:


> Here's a good article from Oregon State with quite a bit of detail and the do's and don'ts, According to the article there are some specific properties needed that aren't in the other compounds so substitution is not recommended.......
> 
> http://owic.oregonstate.edu/sites/default/files/pubs/peg.pdf


This was a very informative article. An i to gather that wood will not shrink at all during drying process when treated?


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## Schroedc

norman vandyke said:


> This was a very informative article. An i to gather that wood will not shrink at all during drying process when treated?



I use Anchor Seal for the stuff I dry and I have noticed some slight dimensional changes and the occasional twist or bow but with a much more controlled drying the odds of the wood checking or splitting is way reduced. I always cut my stock oversized to account for final planing/turning/shaping after it's dry.


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## norman vandyke

Schroedc said:


> I use Anchor Seal for the stuff I dry and I have noticed some slight dimensional changes and the occasional twist or bow but with a much more controlled drying the odds of the wood checking or splitting is way reduced. I always cut my stock oversized to account for final planing/turning/shaping after it's dry.


Is anchorseal peg? I already use that on my green stock. I was looking up peg1000 and couldn't find any. I did find peg400, which appears to be a 40% solution.


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## Schroedc

norman vandyke said:


> Is anchorseal peg? I already use that on my green stock. I was looking up peg1000 and couldn't find any. I did find peg400, which appears to be a 40% solution.



Anchorseal is a different product. @Kevin has used PEG but up above he stated his results were sub par so.........

Reactions: Thank You! 1


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## djg

Thanks for moving this thread to a more appropriate section. I scanned the second cited article and it did answer my question about compatibility with finishes. If the glycol replaces water, then it seems like you'd still be putting a finish over a 'wet' surface, even if it's a water based finish. Sort of like putting a finish on after you've waxed the wood. Now if a blank, etc was soaked in propylene glycol for a time and then that allowed drying, I wonder if the PE would evaporate out of the wood like DNA does? I've never poured antifreeze on concrete and watched to see if it evaporates.
The point of all of this is I can get 5 gal of PE free (yeh, cheap [email protected], I know) and treat cookies with it to help slow the drying process. I've been warned by several of you in the past about being too optimistic about drying cookies, so I'm probably wasting my time.
Thanks


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## Schroedc

I know a guy that dries cookies by cleaning up one face and gluing them to a piece of 3/4 plywood and waxing the top with anchor seal. He seems to get better results but of course you do have to remove the plywood after its dry....

Reactions: Like 1 | Informative 1


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## Kevin

Schroedc said:


> I know a guy that dries cookies by cleaning up one face and gluing them to a piece of 3/4 plywood and waxing the top with anchor seal. He seems to get better results but of course you do have to remove the plywood after its dry....



Thought I'd heard it all but that's a new one on me.

Reactions: Agree 1


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## Schroedc

Kevin said:


> Thought I'd heard it all but that's a new one on me.



Yeah it does work but doubles your dry time since it's only drying from the top. I've thought about trying it with some smaller ones.....


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