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Sterilizing wood with ozone?

Discussion in 'Woodturning Discussion Forum' started by Arthur Crozier, Sep 11, 2020.

  1. Arthur Crozier

    Arthur Crozier

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    I have been doing a lot of research on ozone as a means to kill bacteria, viruses, and insects. The reason I was looking into this was because I want to eliminate potentially transmitting insects in my turning if I sell them abroad. I use a microwave to get the wood to the temperature recommended by the USDA for international transport, and I kiln dry my wood as well but I was thinking of exposing my turnings to ozone as an additional way to ensure I do not transport invasive insects or biological organisms. I know it will not kill eggs but it will kill larva and adult insects. In order to kill everything you need to treat the wood multiple days until the eggs have hatched.

    Ozone is unhealthy to breath and affects all organic products but it dissipates within about four hours which is why it has been used to kill bacteria and viruses on food products since the 1930’s.

    From what I have read ozone is very affective a killing insects and various organisms but I can’t find information if it is used to sterilize wood. I know it is used to bleach wood but I can’t find information about sterilizing.

    Does anyone know if this is feasible or know where I could find information?
     
  2. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Hydrogen peroxide (H₂O₂) is used to bleach wood, but I wasn't aware that Ozone (O₃) was used for bleaching wood. I doubt that the ozone would penetrate to any significant depth. I think that heat is your best option.
     
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  3. DON FRANK

    DON FRANK

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    I would lean towards simply boiling rough turned blanks. That would get the core temperature above the range that anything could survive.
     
  4. Glenn Lefley

    Glenn Lefley

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    Good article on cleaning oak barrels. https://www.anseros.de/ozone-applications/sterilizing-barrels/
     
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  5. Arthur Crozier

    Arthur Crozier

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    What prompted me to ask about ozone here was because I came across an article about eliminating insects and bacteria in grain bins that contained some impressive statistics. Grain bins are not small and with what I would consider relatively short treatments ( 3 to 8 hours) they had 100% kill rates on an assortment of insects using relatively weak concentrations of ozone. The primary issue was re-infestation when eggs hatched. The kill rate was better at higher temperatures because it typically increased the breathing rates of the insects.

    Since a lot of insects that affect trees create holes and passageways and often live near the phloem which is very porous I thought ozone might have a reasonable penetration once an item was turned.

    The bleaching of wood with ozone was mentioned in one of the articles I read, but they didn’t go into detail. I also found articles about changing the colour of wood on violins by using ozone but again there were no details. It was a music forum and you had to create an account to ask questions, which I didn’t do. According to one person on the forum the combination of ozone and lignin produced nitric acid which made the wood brittle. What I couldn’t find out was how long they treated the wood or the strength of the ozone they used to alter the colour of the wood. Also the woods used in violins is extremely thin compared to my turnings.

    I read the article on sterilizing wine barrels. It seems that the ozone does penetrate the cells of the wood.

    I was aware of boiling wood, and that soaking wood for long periods also helps prevent cracking, but I was looking for ways that wouldn’t require long periods to dry. My Swedish uncle owned a sawmill and he would leave log booms soaking in the lake for months. I also came across a YouTube video about a Dutch company that soaked there logs for a year. The explanation was the the saturation affected the lignin in such a way that it reduced stresses on the cellulose when the wood dried which prevented cracking. I don’t know if this was ever confirmed scientifically or if it is just tradition. I imagine the soaking would also help reduce insect infestation.
     
  6. Richard Coers

    Richard Coers

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    None of your research nor DIY methods will account for spit if the inspector at the country you ship to doesn't see approved paperwork saying your wood has been sterilized to some rules they have adopted. If they don't like your documentation, it goes to an incinerator. I'd switch your research to what those countries will accept.
     
  7. Arthur Crozier

    Arthur Crozier

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    I was considering ozone as an enhancement to standards so I thought I would ask if anyone knew of any research on the subject. I have contacted some scientist in Europe that were doing research on ozone.
     
  8. Mark Jundanian

    Mark Jundanian

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    Arthur, in your research did you come across any methods to produce ozone in a hobby workshop?
     
  9. Arthur Crozier

    Arthur Crozier

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    You can buy commercial ozone generators and there are a number of YouTube videos on how to make ozone generators. Commercial components to make your own are available. I intend to make my own system. I thought about using it in my kiln but decided against it even though the higher temperatures would have been beneficial in killing insects. My kiln is inside but I plan to make a plexiglass box that I can put outside and then put my ozone generator and bowls in the box. Ozone generates a lot of oxidation which causes rust so I wouldn’t want to expose my shop to the oxidation. Besides it being used to kill bacteria, viruses, and insects it also isn’t safe for humans, pets, or plants. According to my research it takes up to 4 hours for ozone to dissipate so you have to factor that into how you intend to use it.
     
  10. Dean Center

    Dean Center

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    Thinking out loud, here. If ozone was a safe, effective, economical method for killing insects in wood products, wouldn't somebody have already figured that out and developed a commercially viable system?
     
  11. John Walls

    John Walls

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    If ozone is bad for humans, then my CPAP cleaner, SoClean is bad for me to use? That's how it cleans mask/machine.
     
  12. Arthur Crozier

    Arthur Crozier

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    Ozone is used to clean medical equipment, buildings, and a host of other uses. It has been used on fruits and vegetables since the 1930’s. It is unsafe for “humans to breath” ozone but it is excellent for disinfecting and removing orders. Ozone dissipates in a relatively short period.
     
  13. Glenn Lefley

    Glenn Lefley

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    There are only two treatments that are recognized by Canada Or the Usa I believe. To get a phytosanitary certificate for wood. A heat treatment and the methyl bromide treatment. You don’t want the heat treatment as all the wood would crack. I’ve gotten lots of wood shipments from all over the world and they all require the methyl bromide treatment done by a government approved company. The customer usually gives it to a company that does large exporting of wood and it gets put in the huge size tent and they Pump in the gas for 24 hours I believe at a certain temp. And then issue certificates. Nothing will penetrate bark so that has to be removed.
     
  14. Glenn Lefley

    Glenn Lefley

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    I do know Canada looked into banning ozone generators for home use and realized they did not have the authority to do do. So they did an end run and will not give any ozone generator an electrical approval for home use. So if it burns your home down your liable as it is not ulc or CSa approved
     
  15. Arthur Crozier

    Arthur Crozier

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  16. Glenn Lefley

    Glenn Lefley

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    It was phased out in 2005 but not in critical use areas. As there is no other way to effectively debug wood it is used all over the world for that reason. All my wood from Australia, USA is methyl bromide . I just got a shipment last month from the USA with the certificate stating time and duration of use of methyl bromide.
     
  17. Glenn Lefley

    Glenn Lefley

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  18. Arthur Crozier

    Arthur Crozier

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  19. Arthur Crozier

    Arthur Crozier

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    Thanks. Good to know about the Methyl bromide. Does that also apply to finished wood products?
     
  20. Arthur Crozier

    Arthur Crozier

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    I found my answer about using ozone to remove insects. It does kill insects but it also affects the lignin and cellulose in the wood so I will stick to using heat as a means of eliminating pests.
     
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  21. Lamar Wright

    Lamar Wright

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    Arthur, I agree, heat is your safest way to eliminate bugs.
     
  22. Lamar Wright

    Lamar Wright

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    Arthur, I agree, heat is your safest way to eliminate bugs.
     

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