by Professor Gene Wengert
Q.
I have some specific questions regarding peg.
1. What are the water/peg ratios for mixing it up? The peg I have purchased is in liquid form.
2. Is there some sort of average time for soaking the wood in relation to the thickness?
3. How do you know when a piece of wood has been soaked long enough?
4. How do you test the strength of the peg?
5. Most wood darkens with age--does peg stop this?
6. Is peg food safe?
7. Is it safe to get on the skin?
8. Will any metal put in the solution affect the peg?
9. What is peg made from?
A.
2. 30% solution-- Approximately: 20 days for 1 to 1-1/2 inch thick pieces; 60 days for 2 to 3 inch stock at 70 F. Approximately: 7 days or 30 days for 1 to 1-1/2 inch material at 140 F.
50% solution--Approximately: 15 days for 1 to 1-1/2 inch thick pieces; 45 days for 2 to 3 inch stock at 70 F. Approximately: 3 days or 14 days for 1 to 1-1/2 inch material at 140 F.
3. Experimentation.
4. Measure the specific gravity. For 30%, the SG=1.05. For 50%, SG=1.093.
5. Nope.
6. PEG is used as a laxative when under 1000. Probably not too safe.
7. Probably okay for brief exposures, but see the manufacturer.
8. No, but metal will discolor the wood.
9. Polyethylene glycol (also used as antifreeze when not put into a long chain molecule), but for wood, there are 1000 molecules tied together to form the waxy stuff we use--hence the name PEG-1000.
Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison.
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