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4.1 Water Resistance RW(p) and Acid Resistance RA(p) (Powder Method)
The glass to be tested is crushed to 425 µm ~ 600 µm grains. A sample of this powder equivalent
to the specific gravity in grams is placed on a platinum basket. It is then placed in a flask of silica glass
containing a reagent and boiled for 60 minutes. The sample is then carefully dried and re-weighed to determine
loss of weight (percent) and classified as per tables 3 and 4.
The reagent used for the water resistance test is distilled water (pH 6.5 ~ 7.5). 1/100 N nitric acid is used
for the acid resistance test.
| Class |
1 |
2 |
3 |
4 |
5 |
6 |
Loss of wt
% |
< 0.05 |
>= 0.05
< 0.10 |
>= 0.10
< 0.25 |
>= 0.25
< 0.60 |
>= 0.60
< 1.10 |
>= 0.10 |
| Table 3: Water Resistance |
| Class |
1 |
2 |
3 |
4 |
5 |
6 |
Loss of wt
% |
< 0.20 |
>= 0.20
< 0.35 |
>= 0.35
< 0.65 |
>= 0.65
< 1.20 |
>= 1.20
< 2.20 |
>= 2.20 |
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