Reusing DNA

[Prashun Patel]

I've been using the DNA drying method recently. I've noticed that most people say you can reuse the DNA many times. The thing is, if the DNA is displacing the water in the wood, then over time doesn't the solution in the tank end up with a higher % of water with each drying? I'm hoping it just doesn't matter much.

Any insight appreciated.

[Jim Burr]

Correct on both counts...I've used the same bucket (it's well sealed) for 3 years and put another piece in yesterday.

[Keith E Byrd]

I have used the bucket over and over. But I do now have two buckets. I soaked some black walnut which stained the DNA. I put a couple of other non walnut pieces in it and they came out very dark from the walnut stain. So I now keep two buckets!

[Scott Hackler]

I use the same bucket over and over again. I have even soaked balck walnut and didn't know why, but it didn't stain my lighter woods. I really can't explain that because the juice while turning it stains everything else! If you just add more Dna every so often while you loose it to the wood, it helps maintain a usable % of Dna in the bucket. At least that is my experience.

On a semi-related note, I was fishing out some mango cut offs out of my bucket with my bare hand and later I noticed that my hand smelled like leather. I wonder if wood tannons are related to leather cells in some wierd way. It was quite odd to smell that!

[Dale Coons]

Dave Smith has a blog on alcohol soaking (alcoholsoaking.blogspot.com). He has done quite a bit of testing. The site has a lot of useful info. Over on the right side is a link "Determining Alcohol Percentage". Click on that and read his method for determining how much water is in there. At the bottom of that page is a link to a graph you'll need.

Like others, I've never had any problems, just add more when the bucket gets low. But this will give you a more scientific answer if you want one. He's also kept track of results people have gotten using DNA soak, so if you're interested in a particular species or whatever, you might find it there also.

[Bernie Weishapl]

I have used the same bucket now for over 4 yrs. When it starts getting low I just add fresh DNA. I have soaked walnut and the DNA is almost black but doesn't seem to effect any of the light woods.

[Prashun Patel]

I certainly don't need a scientific answer; just wanted to make sure I shouldn't be changing my DNA more often. I'm on my 7th or 8th rough blank. I have a devil of a time keeping oak bowls from cracking - even with anchorseal.

Oak isn't the easiest to turn or the most interesting to look at, but we have a LOT of it here. The acid (smells like butyric acid) coming off fresh blanks makes my basement smell like sweaty feet.

[Hilel Salomon]

If I'm not mistaken, DNA is harmful if handled. Certainly you're supposed to use it in a well ventilated setting.
Hilel

[Hilel Salomon]

Just to be sure that I wasn't whistling in the wind, I looked it up. Here is what I found:
2. Composition/Information on Ingredients
Ingredient CAS No Percent Hazardous
--------------------------------------- ------------ ------------ ---------
Ethyl Alcohol 64-17-5 91 - 93% Yes
Ethyl Acetate 141-78-6 1% Yes
Methyl Isobutyl Ketone 108-10-1 1% Yes
Gasoline 8006-61-9 1% Yes
Methyl Alcohol 67-56-1 4 - 6% Yes 3. Hazards Identification
Emergency Overview
--------------------------
POISON! DANGER! VAPOR HARMFUL. MAY BE FATAL OR CAUSE BLINDNESS IF SWALLOWED. CANNOT BE MADE NONPOISONOUS. HARMFUL IF INHALED OR ABSORBED THROUGH SKIN. FLAMMABLE LIQUID AND VAPOR. AFFECTS CENTRAL NERVOUS SYSTEM. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. MAY AFFECT LIVER, BLOOD, KIDNEYS, GASTROINTESTINAL TRACT AND REPRODUCTIVE SYSTEM.

-----------------------------------------------------------------------------------------------------------
Health Rating: 3 - Severe (Poison)
Flammability Rating: 4 - Extreme (Flammable)
Reactivity Rating: 2 - Moderate
Contact Rating: 2 - Moderate
Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT HOOD; PROPER GLOVES; CLASS B EXTINGUISHER
Storage Color Code: Red (Flammable)
-----------------------------------------------------------------------------------------------------------

Potential Health Effects
----------------------------------

Inhalation:
Causes irritation to the respiratory tract. Symptoms may include coughing, shortness of breath. Prolonged exposures to high concentration may cause drowsiness, loss of appetite, and inability to concentrate.
Ingestion:
Cause headaches, gastritis, intoxication, blindness and, in acute cases, death.
Skin Contact:
Causes skin irritation, cracking or flaking due to dehydration and defatting action.
Eye Contact:
Can cause eye irritation. Splashes may cause temporary pain and blurred vision.
Chronic Exposure:
Prolonged skin contact causes drying and cracking of skin. May affect the nervous system, liver, kidneys, blood, g.i. tract and reproductive system. Continued ingestion of small amounts could result in blindness.
Aggravation of Pre-existing Conditions:
Persons with pre-existing skin disorders or eye problems or impaired liver or kidney function may be more susceptible to the effects of the substance.

[Scott Hackler]

Hilel is correct, Dna is a dangeous chemical that is very flammable.... BUT so is gassoline, turpentine, paint thinner, paint stripper, wood stain(sort of), acetone ...ect. All of which I have in my garage or shop and all of which you handle and store using the proper method. I wouldn't (and don't) think twice about using Dna. Its evaporative nature actually works to your advantage if you spill or drip some on the floor or bench. 2-3 seconds later and its gone. Gasoline or thinner takes a lot longer to evaporate and will be flammable a lot longer.


It is all in the use of common sence and practical safety.


Prashun, 7-8 blanks? Shoot that is just getting started with a bucket of Dna! I wouldn't even think it being "weakened" until you've surpassed the 20-30 bowl range. :) I don't keep track of the # of bowls, just the level in the bucket. I add more Dna when the level drops noticably.

[Chris Colman]

I recently put a piece of Mulberry into the DNA I had been using for Black Walnut. It turned the Mulberry dark orange instead of its usual bright yellow.

I will let it dry and see how deep the stain is when I finish turn it.

I got some new DNA and keep two batches now.

[Ric Taylor]

Here is my experience: When the DNA is fresh, the wood sinks to the bottom of the bucket. As more and more water is displaced from the wood into the bucket, the wood tends to float. When I need to use a brick to hold the wood submerged in the DNA/water mixture, then I replace the mixture with fresh DNA.

Ric

[Faust M. Ruggiero]

Ric,
I found the same thing. The more used the DNA becomes, the more wood floats in it. Also, since I have soaked quite a few bowls in the current batch, it will darken light woods. I ruined a pear hollow form in it. I didn't weight it to the bottom and when it floated a small portion was not submerged. It stayed white while the rest darkened a bit. I was unable to sand enough to blend the colors. I will probably finish it and burn or otherwise embellish it to hide the difference.
faust