Better Lumber By Drying at Home Inexpensively - WOOD STERILIZATION

[jimithy]

Most people do not believe you can effectively sterilize wood at home. I do not share that view.

My Qualifications

My father quit the lumber business because pine beetles were eating the forests faster than they could be cut... and the remainder burned off. I was in Elementary school at the time and it had a major effect on my life. I was a "whiz kid". I am the only person ever to receive the Dowell Laboratories Award for Outstanding Achievement in Biology twice. I was one of 17 students in the U.S. that was "fast-tracked" by the National Science Foundation (There was paranoia in the early 1970's that the Russian students were way ahead of U.S. students). I was part of a graduate-level Bio-Medical research team at USC when I was 16. I've done a lot since then.

I am not an expert on woodworking. I do know a lot about biology and chemistry.

Sterilization Processes I Do Not Consider Suitable For Home Drying

Pressure processes (Using pressure to increase chemical penetration, autoclaving, etc.)

Tyndallization (3 Days of 212F for 30 min then 1 day at room temperature with facilitates the germination of spores and then kills them)

Copper based preservatives (i.e. Chromated Copper Arsenate (CCA) is bad stuff around homes and banned by the EPA; Alkaline Copper Quaternary (ACQ) often creates a greenish cast and is highly corrosive to steel and other alloys/metals with similar ionization; Ammoniacal Copper Zinc Arsenate (ACZA) is greenish cast and is generally used for marine applications; Copper Azole (CA-B or CA-C) sold as "Tanalith" or "Wolmanized" also creates a greenish cast.

Steaming (20 mi at 212f unpressurized)

EMF Treatments (i.e. Correct application of Gamma Ray or Microwave treatments will kill anything in wood with little effect on the wood itself.)

Brine and White Vinegar soak for a week creates a strong odor and changes the wood chemistry so that certain finishes are not possible, It also encourages corrosion.

Ethylene oxide gas is toxic when inhaled and is a registered carcinogen.


A Sterilization Process Safe To Use For Home Drying

In winter there is a fairly ineffective but popular home process called Reciprocal (or Reverse) Tyndallization. A kiln is heated in winter. When you have a major cold front come through; for a week, each evening turn off the heat and open the kiln to the night-time air. In the day, close up the kiln and heat it. The idea is that insect eggs are tricked into believing it is spring and they hatch. The bitter cold kills them before they can lay more eggs. Doing it over and over encourages germination of more eggs. This does nothing for mold/fungus/spore problems.


The Primary Sterilization Process I Use For Home Drying

After the initial planing preparation of the rough sawn wood, I use multiple methods to control the insect/eggs/mold/fungus/spores/bacteria problems in it.

I mix a strong citric acid solution ( 1 part dry citric acid to 3 parts water) and spray/wipe all six sides of all boards. One day later I mix a strong Baking Soda (Sodium Bicarbonate) or Washing Soda (Sodium Carbonate) or Soda Ash (Sodium Carbonate) solution ( 1 part dry Baking Soda to 3 parts water) and spray/wipe all six sides of all boards. The next day I mix a strong Borax (aka Sodium Tetraborate, Sodium Borate, Boric Salt, or Disodium Tetraborate) solution ( 1 part dry Borax to 3 parts water). I leave that on until I am ready to put the boards into the kiln... at that time I mop it off until the bucket water remains clear.

WHY...

Some organisms (especially bacteria that eat wood) hate certain ph environments. The acid bath followed soon by an alkaline bath does not give them time to adjust.

Borax, Boric acid, and various Boric oxides are fairly effective at insect, mold/fungus, and spore control. Lots of pest control companies use them (Terminix for one) as their first line of defense against termites, carpenter ants, mold, and fungus. Borax compounds generally have low toxicity to people and they do not become fixed in the wood. This allows wood to be treated and then most of the Borax can be easily leached out. NOTE: Pest Control Companies typically add chemicals of questionable efficacy to their Borax based products in order to give them a fancy trademarked name that has nothing to do with what chemicals are in it.

Borax is also a Base so it helps normalize the ph of the wood.

Why it is safe

Citric acid is the main acid in limes and a major food ingredient. I have tested it with a number of species of wood... and various ages of wood (all the way back to multiple types from the mid 1800's. It seems to have no effect. Also, it is often used to remove rust from vintage tools. I have never seen a corrosion problem from it.

Baking Soda is an alkaline substance that is a major food ingredient in most kitchens. I have tested it with a number of species of wood. It seems to have no effect. I have never seen a corrosion problem from it.

Borax is not longer a food ingredient in the U.S. but it is used a lot in food elsewhere. Caviar traditionally has borax added to it. NOTE: If you have trouble obtaining Borax in bulk then use Caviar.

NOTE: All 3 ingredients are available cheaply and in bulk.

I would love to hear what other people might be doing to sterilize wood before drying (or afterwords)

jimithy

[scsmith42]

Jim, you have a fascinating background, and your posts are thought provoking as well. Thanks for sharing the information.

I was aware of the benefits of using boric acid, but was not familiar with the benefits of the other methods that you shared. When I mill large beams that are not appropriate for my kiln, I've used a boric acid product called "Tim-bor" to saturate the beams and boards, to good effect. I will add the citric acid and baking soda information to my knowledge base.

Typically I will sterilize the load at 135 degrees F in my kiln for 24 hours at the end of the cycle. For small quantities, since most attics in our region reach in excess of 135 10 months or more out of the year, another good option for home sterilization of small quantities is to simply stack/sticker them in your attic and store them there. This seems to me that it would have a similar effect to the Reverse Tyndallization process that you mentioned during your posts.

Your information is great - please keep it coming.

Scott

[Glennbear]

Thanks for sharing your knowledge and experience Jim, it is a wealth of information. I have had some root burls stored in my metal storage shed for over a year and it appears that the dramatic summer temps reached out there in conjunction with a fumigation using an aerosol can fumigator have killed off the PP beetles. Scott's comments seem to validate my thoughts but before cutting them into turning blanks I will follow up with a boric acid product.

[jimithy]

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