Re: How much acid in bath?
From my notes.
The traditional electrolyte concentration of 165 grams H2SO4 to 1 liter (1 liter = 1000 grams) of water is 165/1000 = 16.5% by weight. This corresponds to a 9.4% concentration by volume. Since no one commonly weighs sulfuric acid, water, or other liquids, its usually measured by volume in practice.
To sum it up:
Concentrated sulfuric acid; 100% by weight and volume.
Commercial battery acid; 35% by weight, and 19.2% by volume.
"Professional" electrolyte; 16.5% by weight, and 9.4% by volume.
Caswell's 1:2 electrolyte; 6.4% by volume.
LCD electrolyte; 4.8% by volume.
The book quote looks to be prior to the introduction of LCD (Low Current Density) anodizing. It also appears to me to mix the ratios of by weight and by volume. It's confusing enough as it is without the mixing of the different methods. Mixing dry acids by weight is a more accurate method since you don't have to concern with material density but converting ratios takes a bit of figuring. Another way to think about it is a 16 ounce Coke doesn't weigh a pound.
Any questions you have, I'll try to help. I hope I didn't add to the confusion.
SS
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