Treating/preserving bamboo for outdoor use - Ammoniacal Copper Arsenate (ACA) or Copper Chrome Arsenic (CCA)
I was looking at different methods of preserving bamboo/wood there are a few methods that allow for outdoor use which resist pests & rot (if
buried in ground). The two most attractive as far as usefulness/longevity use arsenic unfortunately. One uses arsenic trioxide and the other the
pentoxide.
The options look like this:
Copper Chrome Arsenic (CCA) - As2O5 : CuSO4 : Na/K dichromate 1:3:4 ratio
Copper Chrome-Boron (CCB) - Boric Acid : CuSO4 : Na/K dichromate 1.5:3:4 ratio
(ACA) - CuSO4 & As2O3 - IDK the ratio and IDK where the "ammoniacal" term comes from, maybe ammonia is added to this compound?
I'm also thinking if I use the ACA I don't have to deal with the dichromate, which is pretty toxic as well.
The other options sound pretty nasty - chlorinated phenols:
Trichlorophenol
Pentachlorophenol
I did find that the As2O5 can be made by heating the trioxide under O2 but it also says it can be made with an oxidizer like H2O2, ozone and nitric
acid will convert it but IDK what kind of concentrations are required for this. If I were to try the recipe with the pentoxide, I'm wondering if I
can use 35% H2O2 + As2O3 and then add the appropriate CuSO4 + dichromate since it will have the excess water from the 35% H2O2. I'm sure I will need
to add more water to get it to the concentration needed for treatment.
I'd REALLY prefer to not deal with the pentoxide b/c of how toxic it is, and there are special reporting requirements for it, but if it is made
in-situ and then mixed with the other compounds, IDK if I would ever have to report it. Here's the "community rights-to-know act" that reuqires it...
https://en.wikipedia.org/wiki/Emergency_Planning_and_Communi...
If anyone knows anything about the ACA with the ammoniacal prefix, I'd be very interested in knowing what I need to add to get this compound correct.
I'm wondering if I can bubble ammonia through a solution of CuSO4 + As2O3 until it gains the proper weight, or I can make some I guess - it's not
super easy to buy where I'm at - only ~5% unless you get anhydrous as a farmer.
I have A LOT of bamboo that will need to be preserved. the largest is about 2.75" diameter and maybe 20ft lengths. I have at least 500 pieces and
may have more than that if I find others that want this as well, there is no shortage of the bamboo at the moment. I expect the poles to be at most
4-6" into the ground, so there isn't going to be a lot of this treated wood exposed to the soil (pollution wise) and these are supposed to last 50-70
years with this treatment vs 5-8 with other "natural" treatments, which aren't really much cheaper and MUCH more expensive if you calculate replacing
every 8 years - material, time & labor - that's A LOT of cost compared to doing it with something that can be toxic.
Any suggestions on which way to go I'd appreciate it. If you know of any other methods of long term wood preservation (bamboo), please let me know.
Thanks!
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