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made up a batch of boric wood treatment.

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I have been using the borax, boric acid and antifreeze mixture and I find it to be much better than the borax and boric acid.  Heating to 260 F helps remove water of crystallization from the concentrate.  When using, I use a 1:1 mixture for hardwoods and 2 parts water to one part concentrate for SYP.  This gives about the same coverage for both types of wood but the SYP seems to need more water to get a more even coverage. From what I have read, you should use the working solution within one day but I have found that when I had some left over, it was still usable a week or two later.  There is a little crystallization but it is not near as bad as the borax/boric acid solution is after one hour.  Also with the antifreeze solution, I have not observed the crystals on the surface of the wood. The chemicals seem to penetrate the wood much better.

Pinenut, you didn't use the borax just the boric acid?

Was your mix basically 50 anti freeze 50 boric acid? Have you noticed any corrosion on anything hit with the over spray? I've heard the borax does two things in the mix.
1st it added more boriates to the mix and neutralizes the acidic part of the boric acid. I know boric acid is really a lite acid but wondered if you had problems with anything because of it.


I use 4.5 lb of borax, 3.5 lb of boric acid (roach powder) to 1 gal of antifreeze.  All products are available at Wal-Mart.  You can get the boric acid from in 50 pound bags cheaper than you can at Wal-Mart (even after shipping) but the borax and antifreeze are cheaper at Wal-Mart.  When mixing, I put the antifreeze on the heat and start mixing the borax and boric acid and then heat it to 260 F.

I have noticed a slight bit of corrosion but not much. The lumber is frequently on the FEL when I spray it and there may be light rust spots from the spray.   

fencerowphil (Phil L.):
The ready made commercial Borate products are expensive!  Their source of Borate is Sodium Octoborate, which is very soluable in water.  Making your own saves about 70%.

I buy Borax (Sodium Tetraborate) and Boric Acid from industrial chemical suppliers who sell locally to the factories.  Both are non-hazardous compounds, so no one jumps up and down about selling to the average guy.  (Of course I know the salesman and keep up his wife's piano.  That may help, too.)  Industrial quantities start at 100 lbs on the Borax and 50 lbs. on the Boric Acid.

"Cooking" the mixture of Borax and Boric Acid in glycol does several things:
1.   Borax is hard to dissolve in water, but dissolves magnificently in ethylene glycol
       (dats the anti-freeze, o' course).  Heat makes the process go even quicker.
2.   When you cook, the idea is that the acid loses its water molecule and jumps in with
      the Tetraborate to become Disodium Octoborate.
3.   Unless you use too much Boric Acid, you won't have an "acid" at the end of the
      cooking process.

I only dilute the mix when I have a reason to and use that up, but I have never had any recrystalize.   I only go with 40oz. Borax and 22 Boric Acid per gallon, however.  Not as concentrated as PineNut.  (I didn't even realize you could get that much to dissolve per gallon!)  I sometimes spray the diluted version, but often just use a roller and roll it on full strength.  I keep a 5-gal. paid handy and the roller hanging on a wall which I use over and over again.  Snap on the lid to keep chillun or pets out ...fer shore!

It's always been interesting to me how you can pour the  very warm (not hot) mixture right back into the 1 gal antifreeze jug, in spite of the fact that you have added several pounds of solids into the solution.  Heavy jug!

Phil L.

fencerowphil (Phil L.):
Just a little follow-up on the idea of whether Borate treatments "cooked-up"
this way are corrosive.  I refiltered some left over portions of my mix, so that
it would be clean enough for a spray application.  This caught my eye:
I use #1 steel wool stuffed into the pour spout of a one gallon antifreeze jug
as a giant funnel/filter when I pour up my Home Brew.   The side of the jug is
cut away.  That way I can pour the big pan of the large roaster I use as the
cooker into this large side opening.  (The jug is lying on its side.)  This steel
wool hasn't corroded, in spite of the fact that I have been using this same rig
and the same wool for over two years.   The Borate has concentrated on the
wool over time.  Sometimes the wool is dried out - just the Borate compounds
on it.

No rust.   This seems to prove that the Boric Acid content does indeed become
a part of the larger compound when you cook it, unless  you use too much Boric Acid.

Phil L.                     P.S.  I do a final filtering through a paper paint strainer.


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