Boron treatment for bamboo

[Brian Erickson]

To make my particular type of bamboo furniture (utilizing Guadua angustifolia aff.), I saw the large diameter poles into strips and go from there. The treatment I use against insect attack is a boron compound (foliar fertilizer---sodium octaborate tetrahydrate) in water soultion, which is very effective. The sawdust produced in the various workshop processes is carried to the plantation and spread around, also composted. This sawdust carries some small concentration of boron with it, and I don't know whether this presents a risk or not. Since my workshop is quite small, we are not talking about vast amounts here, but still I want to know what the tendencies are. Am I going to get a buildup in the soils? Are plants going to be helped or hindered? What about the water table? Anyone with a chemistry backgound out there?

[Mark Meckes]

Brian, thanks for bringing forward this very important issue.
As many of us spend a considerable amount of time working with bamboo, we need to know if prolonged exposure to any ingredient we use can be detrimental to our health and environment.
50 years ago we thought nothing about using toxic chemicals to preserve bamboo, and the debate is still ongoing as to what chemicals, and in what concentration should be considered hazardous.
Fortunately, because production of domestic (US) bamboo materials never really eventuated in the last century, we don't have stacks of recycled toxic bamboo laying around in our workshops, creating toxic dust clouds, while being made into new products.

As interest and use of bamboo in the arts craft and construction continues to grow, we need to find the safest methods of treating and preserving bamboo.

In the US at least, there is no `official institution' working on behalf of the bamboo materials/manufacturing industries.

It's essentially down to us to figure things out for ourselves.

Basically, the only clear advice we are given is...

"Individuals receiving the information (on chemical ingredients, application and use) must exercise their independent judgment in determining its appropriateness for a particular purpose."

Here are several internet sources on the subject of boron and boric acid etc:

* International Conference of Building Officials
ACCEPTANCE CRITERIA FOR DISODIUM OCTABORATE TETRAHYDRATE WOOD-PRESERVATIVE TREATMENT BY PRESSURE PROCESSES (http://www.icbo.org/ICBO_ES/Acceptance_Criteria/pdf/ac62.pdf) This is a pdf file.

* Boric Acid (http://www.jtbaker.com/msds/b3696.htm) - Environmental Health & Safety info provided by a chemical supplier.

Here is this link's contents list, illustrating the number and complexity of issues involved in evaluating and regulating a chemical ingredient.

1. Product Identification
Synonyms: ortho-Boric acid; boracic acid; Borofax, boric acid (H3BO3)
2. Composition/Information on Ingredients
3. Hazards Identification

Potential Health Effects
4. First Aid Measures
5. Fire Fighting Measures
6. Accidental Release Measures
7. Handling and Storage
8. Exposure Controls/Personal Protection
9. Physical and Chemical Properties
10. Stability and Reactivity
11. Toxicological Information
12. Ecological Information
13. Disposal Considerations
14. Transport Information
15. Regulatory Information
16. Other Information

Label Hazard Warning:
WARNING! HARMFUL IF SWALLOWED OR INHALED. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. AFFECTS CENTRAL NERVOUS SYSTEM, LIVER AND KIDNEYS.
Label Precautions:
Avoid breathing dust.
Keep container closed.
Use with adequate ventilation.
Avoid contact with eyes, skin and clothing.
Wash thoroughly after handling.

...hmmm

***********************
ToxFAQs for Boron (http://www.atsdr.cdc.gov/tfacts26.html)
- prepared by the Agency for Toxic Substances and Disease Registry,
Division of Toxicology

***********************

The Safe Use of Boric Acid and Boron No. 10 (http://www.natbat.com/docs/boron.htm)
Prepared by the National Cotton Batting Institute Memphis, TN USA
... Used by this industry as a fire retardant in cotton fiber insulation...
quote...
"If you believe aspirin or table salt is dangerous, poisonous or in some other way life threatening, then you probably should not use borates. If, on the other hand, you can rationally look at the comparative data..."

***********************
Opinion & Information on Boric Acid (http://devinefarm.net/rp/rpboric.htm)
By Michael R. Cartwright, Sr
Mastiff Reporter Archive Index
Quote
"I'm writing this article even though a California environmentalist group advised me not to say anything against boric acid and that I would pay dearly for only trying to mislead the public..."

**********************

well, it's quite apparent that short term, high exposure to these chemicals is hazardous to one's health and the environment, and that more research to determine the effects of long term/low level exposure is needed.
Derived from a naturally occurring substance, and considered a `safer' alternative as a bamboo preservative, opinions will probably continue to vary as to it's safety and application of use.

Note: The only experience I've had with borons, is using the Borax Laundry Detergent to soak and wash pieces of bamboo, and the boric acid powder for silverfish and roaches.

~ Mark

[Brian Erickson]

Thanks once again, Mark, for the sleuthing you did on the subject of boron. A very interesting array of sources. Reading them I don't believe I have a serious concern with the disposal of my sawdust, altho the relevant variable is always the concentration. I will simply spread it wider and thinner. On the other hand I learned that boron/borates are also a fungicide which comes as a pleasant surprise to me in this very wet climate. The minimal problems I have with fungal staining are probably minimal due to my use of the boron treatment, a benefit I was unaware of.
Thanks again,
Brian

[Mark Meckes]

We'd appreciate any info that you come across on this subject, Brian.

Boron treatment is considered as being a safer form of chemical treatment to help preserve bamboo against insects (where they are a problem), though I'm unsure to what extent, or for how long it would slow biodegradation of bamboo that is used outdoors in adverse conditions.

Over the last couple of decades many new woodworking and arts and craft products like dyes, glues, paints, varnishes etc. have entered the marketplace, claiming to be `Non-toxic', or the environmentally safest product known.

This is great news, but we must be cautious of interpretations, as no one really knows the long-term effects, or the effects on specific individuals,
being that all of us have different tolerances.

There is also the question of whether the `safer' products perform as effectively, are as long-lasting and durable as the more dangerous products.
An example is the challange to make acrylic (water-based) varnishes as durable as polyurethane (solvent/petroleum-based) varnishes.

Regards,
Mark

[sybelle]

I would use caution given that certain fungi establsih a symbiotic relationship with growing bamboo, making more nutrients accesible to the host bamboo plant.

The boron might kill these fungi with negative impact on your bamboo grove's intake of nutrients.

I am searching for the reference file on this info, will post it asap.

Sybelle

[knome]

Hello all! Just a wannabe bamboo guy in Massachussetts an I thought I would contribute.

Re: Fungus love for Bamboo

ALL soil has fungi in it that are vital nutrient uptake and delivery mechanisms. 'Modern' farming practice kills these organisms, and so that is why you see industrial farms losing yield every year, even with (and BECAUSE of) increase in fertilizer amounts.

http://www.fungi.com/

Now here's a guy who knows! :)

--T

[Brian Erickson]

Thank you, Knome, that's an interesting thread. I will check out the fungus website, but could you enlarge a little on this theme here? I know for a fact that boron is not always a fungicide because I still get some fungal "bloom" on finished furniture made with boron-treated bamboo, IF the moisture level of the wood is still too high. But, on the other hand, as in the situation referred to in my original post, it may be enough of a fungicide (depending on moisture, temperature, and concentration) to kill some fungal communities in the ground and thus upset a delicate balance.....

[knome]

Brian, Im going to guess that what you really want to do is use Boric Acid as an anti fungal after treatment and in the maintainence of the bamboo. I don't think it is possible to completely rid the bamboo of the fungi and one has to occasionally re apply the fungicide.

You could also try Ethelyene Glycol, aka AntiFreeze. Archaelogical folks use it to stabalize very old wood and kill fungus. Propylene Glycol MIGHT work, but Dave Carnell, a retired chemical engineer, swears by ethylene G for this use. He uses it in wooden boatbuilding and preservation.

--T

[Brian Erickson]

Thanks, Knome, for the tip about antifreeze, I will check it out for this purpose. Usually comes with a color additive though.
I use sodium octaborate tetrahydrate, soluble in water, not boric acid. The latter is cheaper but not nearly so soluble.

[bambooda]

Hello Brian,

I've been off the Forum for some time and just logged in to see what was happening and saw your post. I've been using a product called "Solubor" made by U.S. Borax, which is disodium octaborate tetrahydrate and is a soil additive. I asked for literature on this product from the company (which is misplaced at this time), but as I recall the rating for toxicity is very low to negligeable given you don't swallow it by the spoonful - it is basically a soil additive to increase the boron level for certain soils lacking this element. My recipe is one pound to one gallon of water which comes out to roughly 12% by weight, which is maximum saturation before it precipitates out of solution. I've used it for dipping, Bouchorie (sp?), and Vertical Soak Diffussion (VSD). For the effort and my uses the VSD method seems to work the best. I believe this method was developed by Dr. Liese for bamboo preservation in Indonesia. My personal experience is that it doesn't do much to prevent mildew/fungus, but does seem effective against the post powder beetle given an indoor environment. I would not recommend it for outdoor exposures as it is water soluable and will eventually leach out. Hope this helps your research.

Regards, Cal

[Brian Erickson]

Hello Cal,
Thanks for your comments. I believe Solubor is the best choice for bamboo treatment here also, though it costs over $42 a sack. (Is your cost similar in Hawaii?----just curious.) My current preoccupation is the superficial mold that I get on some new pieces recently finished, and my latest solution has been to enlarge and improve my outdoor drying area so that I'm always working with the dryest possible material. I'm only too aware that boron is ineffective against molds, though very effective against termites and powderpost beetles. Have you had any experience with ethylene glycol as a fungicide, suggested by Knome in an earlier post?
Brian

[bambooda]

Hola Brian,

I found two 50 pound bags of Solubor (99.8% disodium octaborate tetrahydrate) at an Ag. Supply store years ago and they were $28- each. I'm still working with that same supply at present so I don't know the current pricing. This works out to roughly 28 cents a gallon compared to a commercial product called "Timbor" which has the same exact active ingredient at 10-1/2% and priced at about $8- per gallon! Boy!, someone is making a killing! I use a variety of propane heating devices to drive out the "oils/resin" from the outside surface of the bamboo that I use for my work (mostly phyllostachys family). The heat also allows me to change the color of the bamboo and straighten the culms out if necessary. I finish with at least two coats of precatalyzed lacquer and I have had no problems with mold after that. I think we have similar tropical climates so I'm not sure what is happening to your bamboo. I use mostly whole culms in my work so I don't really know what is happening to the interior of the culms. When I expose the interior of the culm (splits) and wire brush the inside surface and apply the lacquer I don't get mold either. There are anti-fungal additives that you can buy at paint stores that can be added to the finish that will prevent mold, but I have not tried them yet. I have not used the ethylene glycol, but have the same concerns with the color additive. I have used polyethylene glycol (PEG) on wood and I found it is both a pain in the ass and expensive and makes finishing a problem. My opinion is that harvesting the bamboo when it is mature (5-7yrs) and during the time of the year when the moisture content and starches are at it's lowest (When the new shoots are up and it is the dry season - if you can arrange that...) you will have a product with the least amount of mold problem.

-Cal

[BambuBrasil]

Hello everyone,

I thought I would join this thread because bamboo treatment presents the largest puzzle for me. For several years, I have spoken to countless people and bought every book on bamboo I could get. Even Walter Liese was generous enough to mail me some photocopies on his treatment methods in Costa Rica and research!

However, recently I met Will Pierson from Big Bamboo Trading Company in Miami (www.koolbamboo.com). He imports Guadua Angustifolia ver. Kunt from Armenia, Colombia. He noted that the poles treated with Boric Acid were not holding up in Florida. Apparently, power post beetles are more prelevant in this tropical climate.

He does have, however, some poles treated with Diesel. They have holes near each node, drilled. Apparently, these poles hold up the best.

In Brazil, some artisans use PENTOX which is highly toxic.

At the Brazilian Bamboo Institute (INBAMBU), they are experimenting with NEEM, a natural substance..

Those are my 2 centavos..

Cheers,
João

[Brian Erickson]

Hello Joao,
Thanks for your comments. I think this topic gets confused when boron comes up. Boron is sold in different compounds, depending on the use. Boric acid is probably what most people think of (besides Boraxo), given that it is relatively cheap and used in many households. But it is not very soluble in water and thus not the best compound to use in order to make a boron/water solution. I have seen it in the treatment tank of a well-known bamboo technical mission, and much of it stayed floating around the edges, while at the same time much of the so-called "treated" bamboo in their exhibition space was exuding the dread dust of Dinoderus minutus! Clearly the lower cost of boric acid ( a third the price of Solubor) is attractive, but once again cheap turns out to be expensive if and when the bamboo fails to be protected. I would bet we have just as many powder post beetles here in Costa Rica as in Florida, if not more, but the treatment with Solubor, not boric acid, has proven to be very effective against infestations in bamboo, given the proper handling.
Brian