DNA-Why You Are All Wrong

[Roland Martin]

Wow, Steve! Don't get John going on dish soap now, he may overdose on lacquer You know, a sticky is actually a great idea, this subject can get quite lenghthy and repetative, why not a sticky.
BTW John, this was a very well done piece of work, thanx

[Nate Davey]

+1 for making this a sticky. Sitting in LAX waiting for a flight to the Phippines and this took smoetime to digest. Great write up.

[Kevin Stanbary]

Outstanding! Thanks for this. As I've read (and participated in) the many debates about DNA and other drying methods here and elsewhere on the web, I kept thinking that perhaps we were trying to over-generalize the results.. I think "It depends" sums it up nicely. Well done!

[David E Keller]

... I think "It depends" sums it up nicely. Well done!

You mean that John could have just typed, "It depends"? I hope he doesn't find out...

[John Hart]

You mean that John could have just typed, "It depends"? I hope he doesn't find out...

I am actually laughing out loud

[Jim Heikes]

Water does not react with water. You start out with C2H5OH when you start soaking the wood and you end up with C2H5OH at the end. The only difference is that the DNA is now diluted with water. The process becomes less effective as the water concentration increases. As far as boiling points, ethanol forms azeotropes which boil lower than either component.

[David E Keller]

Water does not react with water. You start out with C2H5OH when you start soaking the wood and you end up with C2H5OH at the end. The only difference is that the DNA is now diluted with water. The process becomes less effective as the water concentration increases. As far as boiling points, ethanol forms azeotropes which boil lower than either component.

Let's keep the language clean here... This is a family site.

[John Hart]

Yes Jim...thanks...and despite your profanity, I agree. When I originally typed this up, I stated that the alcohol bonds with the water, and that is not exactly what I meant. I was trying to figure out a way to word it....because the alcohol moves into the cell, and the water departs, the two interact, and supposedly, there is some interaction with the carbon in the alcohol...that frankly, I don't understand.....And I don't think I want to.

[Alan Schwabacher]

I don't pretend to have expertise in turning, but I do understand the chemistry.

There is no chemical reaction between the water and alcohol, and little reaction with the wood. But they all stick to one another, and when water is present wood swells. The reason you normally want wood to dry slowly is simply that the water is lost from the outside of the wood; if the outside dries first while the inside is still swollen, the wood develops a lot of stress and can warp or crack. What you want is for the water content to decrease evenly throughout the wood, even though it can take a while for water to travel within the wood. If the water moves around within the wood faster than it leaves the wood, that will minimize stresses caused by drying. This can be done either by speeding up water movement, or slowing down water loss. Drying slowly can provide time for movement, while heating to speed up water movement while exposing the outside to moisture (to keep it from drying too quickly) at a gradually decreasing level, as in a kiln, can keep the moisture levels more similar inside to out.

So what happens with alcohol? It also sticks to the wood, though not so tightly as water. It can diffuse in and replace water simply by chance. The reason to change the alcohol is simply that the water needs to go somewhere, and it slowly comes out of the wood into the alcohol, so you are changing the alcohol to get rid of that water. Because water sticks better to wood than does alcohol, you may need to get the water content of the alcohol fairly low to get most of the water out of the wood. Because the lost water is being replaced by alcohol, the wood does not shrink much. But because the alcohol evaporates more easily than water and does not stick to the wood as well, when you do take it out of the bath and let it dry, the alcohol can travel faster in the wood, so it can dry more evenly. If it dries evenly enough, the wood will not warp or crack.

I don't know to what extent the alcohol might damage the cells and provide a freer path for water and alcohol to travel within the wood, or if exchange of water for alcohol allows partial shrinkage of the wood so that when the alcohol goes away there is less shrinkage left to do, thus dividing the stress of drying between the two stages of shrinkage. I suspect this does happen because alcohol based stains are called non grain raising (NGR), and raising of the grain likely depends on swelling the wood. They probably should be called LGR (less grain raising.)

Your title is deceptive: to me, DNA refers to something completely different. But since you describe isopropyl alcohol, you are not talking about denatured alcohol anyway. The nature of isopropyl alcohol is to be poisonous. Denatured alcohol is ethyl alcohol (the kind in alcoholic drinks) with something added to change its nature by becoming poisonous to keep people from drinking it. This is done to avoid liquor taxes, allowing it to be sold at a lower price.

Edit: It looks as though Jim Heikes made my main point more succinctly as I was typing.

[Grant Wilkinson]

Fun and fascinating discussion. Just to add to the general confusion, all the talk about DNA could lead the reader to believe that everyone is talking about the same substance. When I first heard using DNA for drying wood, I tried to find out just which DNA product was being discussed. In Canada, we have, by law, over 50 formulae for DNA. All they have in common is that they all have some percentage of ethyl alcohol in them. As Alan said, what all these grades also have in common is that the alcohol in them has been rendered non-potable by adding something to it. This relieves the tax that would ordinarily apply to it.

[J.D.Redwine]

Would dry wood absorb the water from my used DNA?

[Jim Burr]

Sorry John...Mod and all, about 10 of your original criteria don't matter...it's just organic chemistry and Microbiology. The bottom line is that for some it will work, for some it won't. I did one by the book and it came out great..I did one badly and the final result showed. Perhaps a better use of bandwidth would be to offer a proven, without a doubt, can't miss, only do it this way, never fails soultion rather than trying to disprove what can work. Diffusion has no choice but to work unless it's mechanically changed. This subject is so dead...let's move on...please!!!!!

[John Hart]

Well, I'm not arguing with any of these guys. I work at a chemical manufacturer, but I do not pretend to understand it. I'm just an electronic engineer and the computer guy. I ask questions of our chemists and they explain to me as best as I can understand. If I have it wrong, it is probably my misinterpretation as to what they told me.

But I'll listen carefully to what others have to say....including Mr Burr who thinks I might want to just drop it.

As I said in the beginning, I usually don't get involved in these discussions because they generally go no where. But I thought I'd offer a description of how many variables are involved and that they come into play. I apologize for any ruffled feathers. That was not my intent.

[John Keeton]

That’s why, if you step into a bath tub filled with pure water, and drop a toaster in it, you will not be electrocuted. But, if you’ve been bathing a while and your bath water is dirty…..dropping a toaster in there, results in your immediate demise. (If it’s plugged in)

I have studied your hypothesis at length, Professor Hart, and I think I can accept all of it except this particular statement. I will need to see proof of this - not "hands on" mind you, but "eye witness" will work - preferably at some distance, and standing on dry ground with rubber tennis shoes!

[Ken Hill]

From DNA to a guy in the shower......full circle me thinks.