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Post by bearcat on Apr 4, 2018 6:07:50 GMT -5
Trying to calculate how much resin needed to fill a 1"x1"x6" mold. I come up with 6 cubic inches. If I use .554 as the amount of Alumilite in one cubic inch of volume, then I need 3.3 ounces of Alumilite Clear. So, how many grams of Alumilite Clear are in 1 cubic inch? Is it the same for Alumilite White? Thanks!
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Post by mike on Apr 5, 2018 14:56:34 GMT -5
The mixed specific gravity of Alumilite Clear is approximately 1.08 meaning there is approximately 9 lbs per gallon. So how I would do this by weight is to multiply 9 lbs/gallon times 454 grams/lb which will give us a number of grams per gallon = 4,036 grams per gallon of mixed Alumilite Clear.
There are also 231 cubic inches in a gallon so we need to figure out how many grams we need per cubic inch. So if we divide 4036 grams by 231 cubic inches per gallon it will tell us we need 17.47 grams per cubic inch. To do 6 cubic inches ... multiply 17.47 times 6 = 104.8 total number of grams ... 52.4 of the A side, 52.4 of the B side. I'd probably round up to 55 grams or a little more of each side for what will be left over in the mix cup.
To convert that back into wt oz ... google tells us 17.47 grams = .616 wt oz. per cubic inch. Which multiplied 6 gives you a total of 3.696 wt oz to fill that 6 cubic inch cavity. Then divide that by 2 to see how much A side and B side you need.
Whew ... there is all that math we never thought we would ever need again back in school.
Hope this helps.
Mike
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Post by bearcat on Apr 5, 2018 15:29:05 GMT -5
Mike, thank you for that very complete answer (and using that math we tried to forget a while ago)! Your response is very helpful.
Jon
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Post by Brian on Apr 5, 2018 19:29:47 GMT -5
......................Whew ... there is all that math we never thought we would ever need again back in school......... Mike When I think back
On all the crap I learned in high school
It's a wonder
I can think at all
And though my lack of education
Hasn't hurt me none
I can read the writing on the wall 
Thanks for the Advanced Mathematics 101 class Mike......
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Post by DanO on Nov 8, 2018 9:09:51 GMT -5
Here is a different way to get at it in case your brain is wired like mine.
___.554 ounce____ X ____1 milliliter___ X ____ 1.05 grams____ = 17.2 grams mixed Alumilite per cubic inch
1 cubic inch Alumilite .03381402 ounce milliliter Alumilite mixed
So, if you have 6 cubic inch mold, 6 cubic inches x ___17.2 grams Alumilite___= 103.2 grams Alumilte mixed
cubic inch
Note: My answer differs slightly because Carol at Alumilite just confirmed with me that the mixed specific gravity of Alumilite Clear is 1.05 even though the tech sheet says 1.04.
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Post by DavidP on Nov 11, 2020 21:37:04 GMT -5
Sorry to be reviving an old thread, but this doesn't work at all for me with Clear Slow.
The spec sheet says the specific gravity is 1.04 on that one. Same calculation as above says that would lead to 17 grams per cubic inch. I just made a pour into a mold intended to give a 9 inch x 2 x 0.75 blank (13.5 cubic inches). I used 250 grams based on what I had been using for regular blanks molds of 1x1x6 for that and came up short be several mm in thickness. The result was about 16.5mm thickness instead of about 19mm. The calculation above says I would need 230g, even less than my 250g, while my calculation based on what I got and how much resin I used says I would need 300g to get the intended volume.
Does the resin cure to less volume when it's getting old? It also doesn't seem shrinkage would be this much, so what's going on?
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Post by notoes on Nov 16, 2020 7:33:13 GMT -5
I don't normally try to calculate the resin volume on most of my molds and when I need to do it, I usually use water to get a better idea of the weight. I put the mold itself on the scale, hit the Tare button to zero it out, and then add water until the cavity is full. I then carefully pour the water into my measuring cup to get how much volume needed. The water volume should be close to what you need and give you a better idea of how much resin is needed.
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