Mix Ratio by Volume = 1A:1B
Mix Ratio by Weight = 100A:90B
Specific Volume = 26.4 cu.in per pound
Find out how much resin I need either by volume or weight that can be easily mixed.
Volume to Weight Conversion of Materials
1 cu.in. of Van Aken Modeling Clay (which is the oil clay I use) weighs 30.9 grams.
1 cu.in. of my Carving Wax weighs 25.3 grams.
To get these numbers, I just made a cube that was 1" all around and weighed it. Of course these numbers are just rough estimates.
The head used to make the 4-part mold weighs 23.6 grams. The head is mostly Carving Wax, but also has some oil clay.
If the head was pure oil clay, I would need 0.76 cu.in. of resin.
Volume of resin = Weight of sculpt in grams / Weight of 1 cu.in. of oil clay
Volume of resin = 23.6/30.9 = 0.76
If the head was pure carving wax, I would need 0.93 cu.in. of resin.
Volume of resin = Weight of sculpt in grams / Weight of 1 cu.in. of carving wax
Volume of resin = 23.6/25.3 = 0.93
If you notice I would need less resin if the head was made of oil clay than if it was made of carving wax. The head is mostly carving wax, so I have decided to just go with assuming it is pure carving wax. I will also round up and say the head was 1 cu.in.
Amount of resin needed is: 1 cu.in. (which is volume)
Is that easily measured out? No. So I will convert to measuring by weight.
If a pound of resin is 26.4 cu.in. So 1 cu.in. of resin would weigh 0.61 oz.
1 cu.in. of resin = 1 (lb) / 26.4 = 16 (oz) / 26.4 = 0.61 oz.
So if the head is 1 cu.in. and 1 cu.in. of resin weighs 0.61 oz. Then it is safe to say I need 0.61 oz of resin for the head cast.
So now I need to figure out how much of A and B I need. The ratio is 100A:90B.
Part A = (1.65 / (A+B)) * A = 0.61 / 190 * 100 = 0.32 oz.
Part B = (1.65 / (A+B)) * B = 0.61 / 190 * 90 = 0.29 oz
So, how much resin do I need by weight?
0.32 oz A : 0.29 oz B
9.07 g A : 8.22 g B
But because there are vents and the pour gate to consider, I will increase the amount by 10%.
So using grams, I would need 9.98g A and 9.04g B. Lets just round it up to 10g A and 9g B for a total of 19g of resin.