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Mold in the barrel

Discussion in 'Woodturning Discussion Forum' started by Lou Jacobs, Oct 7, 2020.

  1. Lou Jacobs

    Lou Jacobs

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    I have been filling my two cardboard barrels with recently rough-turned maple and white oak bowls. I just looked and discovered mold (black spots and white fuzz) on several of the pieces. The larger oak bowl on the lathe was first rough turned two months ago. It showed no mold until today. I put the maple bowls in the barrel over the last two days. I was able to turn off the black spots (see photos) but am worried that I’ve got too much moisture in the barrels. The maple, in particular, was shedding water as I was turning it. Most of the pieces in the barrels are not treated with Anchor Seal. That would be counter productive productive, wouldn’t it? Any suggestions would be appreciated. 47D0BB2B-6D2A-4D94-B91C-A51C94B0F2BC.jpeg 312C3BEC-A3DA-4A89-B637-9F48D569CFFE.jpeg 8FE1CDB1-C8BB-47AC-8ADB-6A0A063F8C19.jpeg D2A1AEA7-0A5C-41BF-BBAE-F65598C0650F.jpeg
     
  2. robo hippy

    robo hippy

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    The black spots on your oak are most likely metal stains from the dust on your hands and tools after you sharpen. If you catch it quick, concentrated lemon juice will erase it almost instantly. I make sure to wipe my tools and hands off with wet shavings before applying tool to the wood for final finish cut. As for the mold, on maple, it happens almost instantly. I figure it is the high sugar content in maple, and the mold and other things that like to turn good wood into compost love the sugar for a quick and easy start. Your pieces need a little more ventilation.

    robo hippy
     
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  3. Lou Jacobs

    Lou Jacobs

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    Interesting idea about the black spots being iron stains. I’ll check to see if they come back after I’ve surfaced off the bowl. What would you think about wiping the moldy bowls down with a Clorox solution and leaving out to air for a day or so at a time? I’ve had good luck with the barrels before now, but I think I overloaded them with the maple.
     
  4. Bernie Hrytzak

    Bernie Hrytzak

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    I have recently tried full strength white vinegar and sponge to wash and wipe off the mold (apply a generous amount of vinegar to the surface. Seems to stay off after that.
     
  5. Richard Coers

    Richard Coers

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    I once did a huge stack of oak bowls and put them in my bowl kiln until it was full. Within a couple days, everything was covered with white fuzz. I washed it all down with a Clorox wash and put them back in the kiln. I frequently opened the door for the next two days to lower the humidity. Everything came out fine when dried. No hint of color change from the Clorox. True lemon juice on the black spots and see if they disappear. Probably easier to get than Clorox these days.
     
  6. Don Wattenhofer

    Don Wattenhofer

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    The little black spots are tannic acid, which is common in oak and you will probably notice that the tips of your fingers get black when turning green oak.
    I have gotten mold on green oak rough turnings especially if they are contained without air circulation. I use anchor seal on the end grain areas, never stack them and store in open air. The first time I heard about the "barrel method" I wondered why, but I didn't comment because I had never tried it now I know why not. There are times when I don't want to get the piece all waxy so I used the bag method and occasionally get mold but it never leaves a stain. I have recently once turned several items in red oak that is less than a month from being a live standing tree and had the black spots and even black finger prints and they all disappeared with the finish sanding
    20063Bowl1.JPG This end grain bowl had the black spots and finger prints that all came off with light sanding.
     
  7. Lou Jacobs

    Lou Jacobs

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    Don, thanks for this advice. I’ve wiped all the pieces down with a bleach solution to kill the mold. On about 25 fresh rough bowls (6 oak and about 19 maple) only three oak bowls and two maple seemed to have any mold. I’ll apply Anchor Seal to the end grain on the oak blanks tomorrow. The maple I’m less worried about, but may experiment by coating half of them, and leaving half uncoated.
    I love the bowl you included in this last post. The feet really help make it very special.
     
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  8. charlie knighton

    charlie knighton

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    see u finding plenty of wood Lou....keep experimenting....how are the cracks.....try just putting some blanks in barrels
     
  9. Lou Jacobs

    Lou Jacobs

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    Charlie, you’re right, I can afford to experiment. I plan to. So far the blanks in the barrels are not suffering from cracks. It seems to leave me with a choice between cracks or possible mold. As Don suggested above, the mold seems to be not more than skin deep, so I’ll coat some, put some in the barrel, and keep an eye on them. Time will tell.
     
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  10. JeffSmith

    JeffSmith

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    Bleach will work for a while - it kills the mold until it evaporates off, leaving the water component behind; the water can stimulate growth of more mold. Living in the damp part of the Pacific Northwest, mold is a recurring problem. Several years ago a chemist friend suggested misting on a solution of Boric acid instead of the bleach. It leaves behind a residue of the boric acid that prevents further growth better and far longer than chlorine bleach and doesn't alter the color of the wood. Boraxo or any of the boric acid powders you find at the hardware store work just fine. Dissolve in water and keep it in a spray bottle.
    Robo's suggestion of more ventilation seems like a good idea. When roughing very wet wood, I give them a spray of boric acid then stack them on the shop floor on edge and let them sit for a few days until the surface is pretty dry. After that they're stacked on wire shelves until dry. I check every now and again to make sure they're still mold free - and give them a spray if I see anything growing.
     
  11. Lars Hansen

    Lars Hansen

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    Lou, you may have missed this recipe from an older thread. I use it on Maple, Birch etc. to prevent mold:
    One (weight) part citric acid (C6 H8 O7) to five parts warm water, stirred, cooled and applied to the fresh cut surface. Cheap, very little bleaching effect and the mold doesn't even start.
    Anchor seal works fine on top of it.
     
  12. Lou Jacobs

    Lou Jacobs

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    Lars and Jeff, thanks so much for both citric acid and boric acid. Sounds like both are the same principle. I’ll start experimenting!
     
  13. robo hippy

    robo hippy

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    I am wondering if the boric acid is also a bug repellant... I know a boric acid powder is good for killing powder post beetles and ants....

    robo hippy
     
  14. Lars Hansen

    Lars Hansen

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    Come to think of it: They used to add a few drops of citric acid to hide glue to prevent mold...
    No idea about bug killing qualities, though..

    Lars
     
  15. charlie knighton

    charlie knighton

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    Lou as your wood collection/hoarding expands your will decide which woods need the barrel and which outside off the ground covered. Oak in the barrel...cherry iffy.....some in some out ....maple out....bradford pear out......etc etc
     
  16. Lou Jacobs

    Lou Jacobs

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    I’m beginning to realize that Charlie. Thanks! I’m expecting a delivery of some citric acid today, which I’ll treat the maple with. Then find a quiet place for it in the shop to allow it to begin drying. Oak is already back in the barrel, where it has been doing well for the past few weeks.
     
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  17. Gerald Lawrence

    Gerald Lawrence

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    Short answer is YES. Mix boric acid and sugar for roaches, been doing that for years. CAUTION this is poison to children and pets also be careful notto inhale the dust. If inhaled in large enough quantities it coats the bronchioles and stops Oxygen absorption.
     
  18. Don Wattenhofer

    Don Wattenhofer

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    This thread has seen many comments and solutions for removing mold but no one I believe has indicated that they have had stains in the finished product if the mold was not removed and I know I haven't. I would be interested to hear about any lasting stain problems.
     
  19. Lou Jacobs

    Lou Jacobs

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    It’s a good question, but I’d rather not have the mold start, as I’m concerned about the potential for allergic reaction to mold and also would prefer not to create an environment in the shop where mold has a foothold. If mold on wood is anything like bread mold, or other fungi on wood, filaments go deep pretty quickly. Clearing it from the surface, unless with a toxic agent like one of those previousOy mentioned, is only clearing it from the surface.
     
  20. robo hippy

    robo hippy

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    Hmm, I have had mold stains that would not come out. If I remember, the end grain spots would penetrate all the way through the bowl wall. The side grain spots could be turned off.

    robo hippy
     
  21. Paul Gilbert

    Paul Gilbert

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    I am a bit puzzled about using citric acid as a mold inhibitor. I once was a chemist specializing in water treatment. We used a low pH agar to cultivate fungi and inhibit the growth of bacteria. Fungi love an acidic environment.
     
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  22. Lou Jacobs

    Lou Jacobs

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    Paul,
    You throw a new twist into the question. Thanks for raising this. I received my delivery of citric acid yesterday. I’ll now be more careful about conducting a careful experiment. I’ll choose a few of my maple rough turned bowls to treat with citric acid and leave out, a few more to leave out untreated, a few to coat with anchor seal and leave in the open, and a few to treat with anchor seal and put in a barrel. I’m dedicating one barrel to this experiment, as I want to leave the oak, as Charlie suggested above, and other species I’ve got drying (locust, mulberry and ash) unaffected.
     
  23. Lou Jacobs

    Lou Jacobs

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    Paul, are you sure you’re remembering correctly? All my quick internet research indicates citric acid kills mold. (I had a client who liked to say he got his medical degree from The New York Times. I realize my chemistry education from the internet might be equally valuable, but on this issue, it looks solid).
     
  24. Paul Gilbert

    Paul Gilbert

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    Lou - you are right about citric being used as a mold inhibitor. When I said that mold loves an acidic environment that was also correct. I the difference is how acidic. My quick look seems to say that fungi thrive at a pH of 4.5 to 7.0 (7.0 being neutral). At pH's above 7.0 bacteria thrive and fungi are inhibited. Our petri dishes for bacteria were buffered some where in the low 8's, for fungi in the mid to high 4's. When the acidity level is driven way up (or pH driven way down) by organic acids at the % range all of the preceding is moot. Sorry about my mistake. Please note that I said I was a chemist. Microbiology was something that got thrown into my speciality, but I never really mastered any part of that discipline that was not related to water treatment.
     
  25. Lou Jacobs

    Lou Jacobs

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    No apology necessary at all Paul. I didn’t return the citric acid! My first degree was in forestry, but I morphed over to social work (don’t ask how). I still am drawn to the forestry - obviously, I’m a turner, among other wood and woods related activities - but I remember enough of the forestry to be dangerous, and every once in a while get a jolt when I realize how far the field has moved, and how much I’ve forgotten, since I was in school.
     
  26. JeffSmith

    JeffSmith

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    Yep - same stuff, just in a diluted solution. Haven’t used it on wood with an infestation, but it wouldn’t surprised me if it worked the same. I bought some extra and ran a line of powder around the foundation of our house - keeps the ants and most bugs away (we live in the forest...)
     
  27. Lou Jacobs

    Lou Jacobs

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    This was curious. I just finished applying a mist of citric acid solution to many of the blanks. Originally it seemed that the maple was where most of the mold occurred, however I found this white oak blank with a band of mold right at the edge between heartwood and where sapwood began. Mold was growing only on the sapwood. B9DE3780-174C-4BA9-AF80-3274F86CFCF6.jpeg
     
  28. Don Wattenhofer

    Don Wattenhofer

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    The 4th picture on the start of this tread showed the same thing on a white oak rough turn.
     
  29. Lou Jacobs

    Lou Jacobs

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    You’re right. I assumed then that it was because it was in contact with one of the maple bowls in the barrel. It was cleaned off, and in the barrel with only other oak pieces. I’ve now taken even those out of the barrel and sprayed everything with citric acid.
     
  30. Timothy Allen

    Timothy Allen

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    That's the same piece in both pictures, is it not?
     
  31. Lou Jacobs

    Lou Jacobs

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    Yes, it is. First before bleach treatment. Then after bleach and the a few days later, citric acid.
     

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