hi,do we need to buy a hanneman specific gravity scale for test 4?as they seem really expensive and hard to come by.Do we need to measure specific gravity for test 4,if so how else can u do it without a hanneman scale?
Hi, not sure how much you paid for the scale and the SG contraption. I’ve got a set for $60.-. It really works to my entire satisfaction.
Pricewise, a converted powder scale could be a reasonable alternative.
Does anyone have experience using such a scale for SG testing?
Hi SG test is not absolutely needed to pass test 4 I did it with out , But you will need the RI , optic sign, microscope (inclusions are your friends) ect. If you do not have a microscope and have not spent some time working with one may be SG is a good way to go. In collage we used SG tests the school had a very expensive set up and it was still a pain in the butt. You must clean and degrease the stone really clean it, look at it with a lope 20x, if you have one ,if you can see any fine polish marks you may have it clean enough now clean it one more time . Distilled deionized water only, The ions in the water along with the grease can case micro bubbles that will (float) the stone this is a real problem with small stones. The hanneman scale saves you some math.All this said if you are comfortable with doing SG test it is a way to go and you some times dont have to mess with the RI fluid . Oh you will most likely need the RI s for test 4