A recipe for mold inhibition of 200ml hydrogen peroxide/200ml H2O/20 mg boric acid has been posted here in the past for roughouts/twice-turned pieces. Would it affect the finish on once-turned pieces? Should it be rinsed off after application?
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Hydrogen peroxide/ boric acid for mold.
- Thread starter Kevin Jenness
- Start date
The peroxide (H2O2?) and water will simply evaporate, and pretty quickly, leaving behind the boric acid (I think). It won't soak in enough to affect your final turned surface. Peroxide kills bacteria/germs, but I do not know if it will affect mold like chlorine will. (I would not put chlorine in that mix!) The boric acid will help with insects, but mold is everywhere on the planet (even you after stepping out of the shower), just waiting for the right conditions to sprout. Nature's little garbage men, along with flies, and... I don't know if boric acid diminishes the chances of mold formation. Temperature, the right moisture, calm air, and an organic material, like wood, to munch on is what promotes mold growth.
I’ve used this formula - with high concentrate peroxide (like baciquel sp? - used in pool maintenance) for years now with no problems. It works well when mold is a problem. Not certain it’s as effective using drug store peroxide. Also helps keep insects out of the shop. I use it on our local woods - maple, madrone, alder, etc - never detected any change to the finish or residual effects. Most of my work gets boiled after roughing out, then sprayed after initial cool down and surface drying.
Jeff, I got the recipe from one of your posts and am using 12% peroxide as suggested. I do mostly once-turned work and have been getting instant mold spots on some pieces (sugar maple and yew recently). How do you think the formula will work with finishes when the surface is not turned again or sanded heavily?
I’ve generally either taken a light finish cut or sanded (usually both) even when once turning pieces, so I can’t say what affect it may have. Generally, anytime I use water containing treatments it’s going to raise the grain to some degree and require at least a little sanding. My experience has been that allowing the piece to dry then light hand sanding before applying the finish (for me it’s usually either a penetrating light oil finish or Osmo top oil) shows no change from no treatment.I do usually finish up with a coat of wax - ren or paste.
Instant mold spots? How soon after turning? If it’s instant, sounds like it could be a tanin reaction. Sure it’s mold?
Instant mold spots? How soon after turning? If it’s instant, sounds like it could be a tanin reaction. Sure it’s mold?
Thanks for the reply, that's helpful. Do you think the boric acid is necessary to inhibit mold, or is it in there to discourage insects?
Not literally instant, but within an hour or two of putting a piece into a paper bag. I made several sugar maple bowls that showed grey spots under the dilute glue sealer I applied to the end grain, deep enough that they may not come out in the second turning.
Not literally instant, but within an hour or two of putting a piece into a paper bag. I made several sugar maple bowls that showed grey spots under the dilute glue sealer I applied to the end grain, deep enough that they may not come out in the second turning.
I just google searched the term "does boric acid kill mold". Short answer seems to be yes, but I did not read far enough for an authoritative answer or source. It also serves as an insecticide when I changed my search from mold to insects.
Here in alberta in the summer I have to let the bowls sit for a couple of days before putting sealer on, hoping for no cracks, otherwise I will for sure get mold under the sealer. Paper bags for me have just given me mold issues within a day here.
Will have to try some of the recommendations here