06-14-2012, 09:41 AM
Phosphoric acid can be bought cheaply for Hydroponics purposes, they use it to lower the pH of the nutrient solutions they use, so they sell it at the maximum possible concentration. I last paid 7 pounds for a litre, In Australia I used to pay $10-15, it is quite thick and heavy as well, always a good sign that your acid is concentrated.
I've not used it on files though, I would guess it's really good at cleaning off the rust which is the primary use for phosphoric acid, but it doesn't eat away much metal.
My Dad used to say that you use Sulfuric acid to sharpen files and it works by taking an even amount of every face of the teeth, which leaves the tips of the teeth sharper even than they were when new.
I've not used it on files though, I would guess it's really good at cleaning off the rust which is the primary use for phosphoric acid, but it doesn't eat away much metal.
My Dad used to say that you use Sulfuric acid to sharpen files and it works by taking an even amount of every face of the teeth, which leaves the tips of the teeth sharper even than they were when new.
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