[JC]

I have a formula for wood preservative and fire protectant. It consists of 2 cups boric acid, 9 cups water, 1 cup propylene glycol. I heat the water with the boric acid to near boiling (while stirring) to dissolve it. Next I add the propylene glycol. This stays in solution while warm but as soon as it cools the boric acid becomes hard crystals.
How can I make this formula to keep it combined in liquid form? Any good variations on the recipe ingredients?

[billnotgatez]

When you warm it up again do the crystals dissolve?
Do you have to stir it as well?

[JC]

I haven't tried warming it again. When I mixed it the first time I stirred it; stirring it now does not keep the borax in solution. What is a good temperature to heat it to now that the mixture contains the propylene glycol? Do I need to worry about getting it too hot?