PEG or polyethelene glycol

[Paul39]

I did a search and found one one reference in 2007.

Has anyone used it recently to stop cracking? How well did it work?

Process is to rough turn green wood and immerse in PEG for weeks or months, then finish turn.

Research indicates the turning can only be finished with polyester varnish.

[ticklingmedusa]

Pentacryl might be a good alternative
Pentacryl FAQ, Preservation Solutions (http://www.preservation-solutions.com/faq-pentacryl.php)
Not sure if it's available down under.

[Ironwood]

I havent used it myself, as I dont do much green turning these days, but I remember some people have been having luck soaking their blanks in detergent and water.
A search on the subject should bring up a couple of old threads.

[Paul39]

I found an archived Woodturning Forum thread that referred to Ron Kent's use of detergent and water.

I found a freshly uprooted Japanese Yew at the side of the street Thursday. It was so heavy I couldn't get into the van. I stuffed the top part in the back and tied it on the back and dragged it 4 blocks to the front of my house.

I had it home at 3:00 and by 6:10 I had the tree reduced to a trunk and the outside of a bowl roughed out. I hollowed it yesterday and today started soaking in 50 - 50 Ajax Liquid Dish Detergent and water.

The trunk is about 4 feet long and full of bulls eyes, bark inclusions and crazy grain. This bowl came from 1/4 of the left end of the trunk.

I have maintained for years that no matter how you treat timber, some crack and some don't. We will see.

P. S. I love the Woodfast.






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[rsser]

Nice work Paul.

...

From memory, PEG replaces the water in a piece. It was once touted as a silver bullet but it was exxy and changed the properties of the timber.

LDD soaking is sposed to reduce cracking as well but may not penetrate that far into the timber. An alt. is soaking in denatured alcohol and some folk swear by this.

Rough turning while green and sealing the end grain with emulsified wax is my first choice.

[Ed Reiss]

Paul, Ed Moulthrop used peg for all his turnings and years later the finish "blushed". He had a lot of pieces back for repair.I know he lost a lot of $$$ because of the issue.

You might want to get in touch with him and find out just what the finish was and steer clear of it.

[tea lady]

Isn't Glycerin derived from wood somehow? :think: Or is it soap making. :hmm: Wouldn't it just try and keep the water in, instead of replace the water and so assist in drying? Isn';t it put in hand cream for just that reason? Not that I've tried any of these things (Except hand cream:doh: ), but metho seems like it would be the more useful soaking stuff. :shrug:

[Paul39]

Thanks for all the replies. For now I'm going to try the 50 - 50 detergent. I have a bunch of fruit wood and soppy wet timber just off the stump.

There is enough to have half a chunk of timber in the juice, and the other half rough turned and put in layers of newspaper and slowly let dry.

See: Ron Kent (http://www.ronkent.com/techniques.php)

AS Ron went from PEG to the detergent, and sells some pretty fancy stuff, I'll follow along without trying the PEG.

I'll let you all know how things turn out.

[turnerted]

Paul
Back in the days when I was still working ,I used to use PEG in the laboratory although not for removeing water from wood . We used to use it for concentrating aquous solutions . It is expensive .
I have seen reference to it being used by marine archaeologists to stabilise old ship timbers .I think it is also used in some polishes .
I think the detergent or alcohol are more practical options or even just soaking in repeted changes of water for a few weeks helps . The theory is that the water dilutes the more viscous sap making drying easier .
Ted

[powderpost]

I have in the past rough turned a lot of bowl blanks. The blanks were stored in card board boxes full of sawdust and shavings, cheap and 100% effective. The blanks were weighed periodically (about monthly) to guage weight loss. They were finished off when there was negligible weight loss. One bowl from a local pine was finished and polished six weeks, using this method, from cutting the tree down. Different timbers will take different time spans to dry sufficiently to finish off.
Jim

[rsser]

I leave my rough turnings out for a couple of weeks, with endgrain sealed, just to keep an eye on creeping cracks. If small ones appear I'll squirt some cheap CA into them and that normally does the job. Bigger ones, the bowl goes into a plakky bag for 2-4 weeks. Hardwood; not softwood - that'll be claimed by mould.

I also use a cheap pin-type moisture meter and when the rough turning is done write the figure between the pin holes. That's just a relative measure to come back to when I estimate the thing is ready to be finish turned.

Jim's approach is a good one if you're working in volume.

Another variable is when the tree was felled. In winter here in SE Aus the moisture content is lower usually and there's less faffing around with drying.

[hughie]

Different timbers will take different time spans to dry sufficiently to finish off.

my findings as well.



Pentacryl might be a good alternative
Pentacryl FAQ, Preservation Solutions (http://www.preservation-solutions.com/faq-pentacryl.php)
Not sure if it's available down under.


Last time I inquired I had to buy a oil drum full :C bit much I thought :U plus shipping . It was not available here retail.