DNA soaking for blanks

[keithz]

I am sure this topic has been covered, but I was unable to find anything is a search on it, so I am asking these questions.

Does anyone soak green pen blanks in DNA? If so, how long do you soak for, and how long does it generally take for them to dry and be ready for turning?

I appreciate any dialog on this subject.

Thanks in advance.

 

[wdcav1952]

http://www.penturners.org/forum/topic.asp?TOPIC_ID=17273&SearchTerms=DNA,drying

Try this link for some information on drying blanks.

 

[Dario]

Keithz,

DNA drying works by osmosis. It adsorbs (with the "D") water in the blank replacing it with alcohol. When you take the blank out of the solution, you have less water (more alcohol). Since alcohol dries faster, your blank will dry faster.

Several factors that will affect the drying are:
1. DNA freshness. Re-used DNA will have water in it already and will be less effective.
2. DNA volume. The more DNA you use, the more it can dilute the water it is taking out of the blank(s).
3. Length/duration of soaking
4. Air circulation
5. Wood type
6. Humidity
etc.

So there is no fast and easy answer to your question. Most I've heard/read soak their blanks for a day and dry for a week.

If you are in a hurry, try microwave...it is much faster. The rest can dry with the DNA treatment or just the natural way []

 

[keithz]

I guess I should have stated that I know how and why DNA works, I have been using it for bowls since Dave Smith introduced it.

I was mainly interested in finding out if others used DNA soaking for green pen blanks and what their experience was.

I currently have some cherry, mulberry, and siberian elm soaking. I put them in the DNA last night at 10PM and will be removing them after work today, about 5PM. That's a 18-19 hour soak. I will then allow them to dry for at least a couple of weeks, maybe more. I am in no hurry for them.

 

[Joe Melton]

After cutting down a largish elm tree in the back yard, I made about 50 bowl blanks and then cut the remaining parts into about 250 pen blanks. I started some experiments with fresh DNA, measuring how long it takes to reach equilibrium moisture content as a function of duration of the soak. I put all 250 into two plastic joint compound buckets, divided between the two with about 2.5 gallons of DNA in each. This was enough to keep them submerged, with weight on the blanks.
I'm at work now and don't have my papers with me, but I do remember that a day or two in the DNA is not enough time. Once the blank is removed, the alcohol leaves quickly, but then the blank seems to be on a normal drying schedule, but certainly further along on that schedule than if it had not been soaked. As I recall, the moisture content was at about 14% after a day or two (from in the high 20s when wet). After two or three weeks of soaking, the moisture in other samples a day after removal was down to about 10%. Here in Colorado Springs, equilibrium is about 8% at this time of year, so this was very close.
An advantage of even a short soak, in addition to speeding up the overall drying schedule, is that the blank doesn't seem to want to crack or curl, as it almost definitely will if it is cut into final size when still wet. Elm, at least, will.
I put a blank that was removed after two days, and was about 14% wet, on the top of my gas water heater and two days later it was down to about 8% and ready to turn. I made a nice pen from it and, a week or so later, it appears to be stable.
I would think that species will vary in terms of permeability, so a longer soak might be required for more dense woods. Also, different woods will probably crack or curl at different moisture content, so some species will probably require a longer soak to get past the point of cracking or curling.
My conclusion is that DNA definitely shortens the time to dry pen blanks. I've not compared it to microwave drying.
Now to find a place to store another 249 blanks!
HTH,
Joe