density of alumilite

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jason_r said:
I know I've seen this number somewhere, but can't find the post here
or on their site.

What's the density of alumilite (g/fl oz)?

Thanks
Click to expand...

don't know that one, but it is .554 oz / cubic inch.. I'd have to dig out
conversion notes I've scribbled on pieces of paper in the 8th grade..
 
not sure I understand.. grams and ounces are both weight, no?
there's 28.47 grams in an ounce? Are you using a container that
has weight marked on it and you're going by that? Liquids have
different weights depending on their specific gravity.

If you fill two containers to the same volume, one with water and
one with PR or alumilite, they will have different weights. I've got some
molds marked with a line (fill to here) and if I pour Alumilite the weight
is different than if I pour water. I've under-filled molds by mixing up
those numbers..
 
According to the MSDS

Alumilite White
Part A/B - Specific Gravity 1.05

The links are broken to the MSDS for Clear but I seem to recall that A and B had slightly different Specific Gravities from one another that averaged to 1.08.

For those unfamiliar with Specific Gravity this is the density relative to water which has a Specific Gravity of 1.0 so you can calculate how much mass you would need for a given volume of water, multiply by 1.04 for Alumilite White and that's how much mass you need for that product.

I do believe that Alumilite contracts slightly upon curing but thats hard to tell for sure
 
Crystal Clear also has a specific gravity of 1.05, according to the msds that came with my last order.

GK

holmqer said:
According to the MSDS

Alumilite White
Part A/B - Specific Gravity 1.05

The links are broken to the MSDS for Clear but I seem to recall that A and B had slightly different Specific Gravities from one another that averaged to 1.08.

For those unfamiliar with Specific Gravity this is the density relative to water which has a Specific Gravity of 1.0 so you can calculate how much mass you would need for a given volume of water, multiply by 1.04 for Alumilite White and that's how much mass you need for that product.

I do believe that Alumilite contracts slightly upon curing but thats hard to tell for sure
Click to expand...
 
The reason you need to mix alumilite by weight is because the 2 parts have different specific gravities. (I think) One part of the resin has a different volume by weight than the other part. I bought a postal digital scale to weigh out the resin parts A and B. It will weigh to 0.1 oz. so I figure that will work.
 
Alumilite does not need to be measured so precisely. I think some folks are getting a little too hung up on the "equal" in "equal parts by weight". I have always used a cheap old dial postal scale that has .5 ounce graduations. I get close to my mark and I am good to go. If I am doing 6 ounces, I may actually have 3.29485736 ounces of A and 2.84739274 ounces of B. No big deal at all. On my scale, they show basically 3 of A and 3 of B and that is close enough. Don't make it harder then it needs to be!

I have been doing this for a long time and have never had a failure due to improper ratio. In fact, the only failures I have ever had (2 to be exact) have been foaming because my material was not dried enough. That is after using nearly 100 gallons of the stuff and every formulation they make!
 
NewLondon88 said:
don't know that one, but it is .554 oz / cubic inch.. I'd have to dig out
conversion notes I've scribbled on pieces of paper in the 8th grade..
Click to expand...

Specific Gravity can basically be calculated as the Weight in grams of a liquid divided by the volume in milliliters of the liquid at 25ËšC. If you weigh out 100 milliliters of DI water, it will weigh 100 grams. 100/100 (weight in grams / volume in milliliter.) will give you 1.000, so DI water has a Specific Gravity of 1 (the standard)

Using the number .554 oz / cubic inch, in metric. One cubic inch is equal to 16.38706 milliliters. .544 of an ounce is 16.92 grams. So 16.92/16.38706 gives you a Specific Gravity of 1.03
 
Ok.. now that I've figured out the reason I couldn't login was
Firefox, I can reply here.

Specific gravity of 1.05 yields:

31 g/fl oz
17.1 g/in^3


As for worrying about how precise to make it, my HF scale will
do grams and I try to match A/B to a gram or 2 since I've not done
enough to test the tolerances, and because a 100g mix is
a large one for most of my pours.

The biggest reason I wanted this was for planning. If I'm doing a
pour of 5 fl oz of Alumilite in 3 colors, it's easiest to figure out
how much of each I want, then make sure the total weight comes
up to 155g. No marking on cups, no grumbling about how much
I left in the cup, no half-full molds. And since I know how much
resin I'm going to use, I can make sure to put in the right amount
of pigment the recipe calls for.
 
jason_r said:
Ok.. now that I've figured out the reason I couldn't login was
Firefox, I can reply here.

Specific gravity of 1.05 yields:

31 g/fl oz
17.1 g/in^3
Click to expand...

OK, I'm lost. Alumilite's web page says .554 oz/in^3
Doesn't that convert to 15.7056 grams?
 
My simple experience agrees with Curtis. I put away the postal scale, and now do equal "squirts" from my gallon size alumilite pumps.

Tom
 
NewLondon88 said:
OK, I'm lost. Alumilite's web page says .554 oz/in^3
Doesn't that convert to 15.7056 grams?
Click to expand...


128 fl oz / gallon
231 in^3 / gallon

0.554 fl oz / in^3

31 * 0.554 = 17.1 g/in^3 (at least according to my calculator)

If we keep this going we'll have a big enough table to put in the library.
 
ok .. I guess.
Maybe it's because I'm not sure where the fluid ounce comes into it.
They gave the weight as ounces, not fluid ounces.
Fluid ounce is volume. So is a cubic inch. Wouldn't that be a constant?

I'm getting more confused.. and I was doing OK at first.. :tongue:
 
Charlie,

I think they are trying to complicate things way too much! Alumilite is .554 ounces (weight) per cubic inch. That is the bottom line information that Jason was looking for, I believe. If he needs it in grams, then I am sure the math can be done pretty easy.
 
Hmm.. from Google:

1 ounce = 28.3495231 grams
1 gram = 0.0352739619 ounces

So:
128 fl oz / gallon
231 in^3 / gallon

0.554 fl oz / in^3

31 * 0.554 = 17.1 g of alumilite WC / in^3 (at least according to my calculator)
17.*.0352 = 0.603

Yes, way too precise. But from these numbers I don't think the
alumilite site was referring to weight when it said 0.554 - that #'s
on the page for calculating the volume of stuff you need for casting.
Which makes sense, since the densities vary.

I just wanted to measure with my scale instead
of a measuring cup.
 
jason_r said:
Yes, way too precise. But from these numbers I don't think the
alumilite site was referring to weight when it said 0.554 - that #'s
on the page for calculating the volume of stuff you need for casting.
Which makes sense, since the densities vary.

I just wanted to measure with my scale instead
of a measuring cup.
Click to expand...

That's where I thought we started.. somehow we got all turned around
with math.

From the Alumilite website:
Amount of Resin Needed to Cast a Part

top
Note: There is .554 ounces in 1 cubic inch of Alumilite Resin.
 
NewLondon88 said:
Note: There is .554 ounces in 1 cubic inch of Alumilite Resin.
Click to expand...

That's the problem. It should say:

"one cubic inch of alumilite weighs .554 ounces",
or

".554 fluid ounces of alumilite equals one cubic inch"

So which one is it?

Tom
 
TomW said:
That's the problem. It should say:

"one cubic inch of alumilite weighs .554 ounces",
or

".554 fluid ounces of alumilite equals one cubic inch"

So which one is it?

Tom
Click to expand...

1 fluid ounce equals 1.80468 cubic inches.

Ounce is a measure of weight. Fluid ounce is a measure of volume.
So the second one won't work.. it would be like saying that two gallons
equals one gallon.
 
Up at the top, where the calculator outputs its answers it says:
"Fluid ounces of casting resin needed:"


They can't say 0.554 oz of Alumilite = 1 cubic inch and mean weight
since the different resins vary.
 
Last edited:
When you reference weight/volume, the first is always WEIGHT. Specific Gravity is always calculated as Weight over Volume.

The ounce in 0.554 oz / in^3 is a MASS ounce, not a fluid ounce. They are saying that a volume of 1 cubic inch weighs 0.553 ounces (0.03463 of a pound, 15.71 grams etc)

That's one of the problem with US/British weights, an 'ounce' can refer to a weight or a volume. In the above example, the oz is weight, not fluid.

Give me metric anytime. It's much more precise and the calculations tend to be easier.

The main reason that the US will never go metric is that metric is too precise, and we are not always precise. There is no metric equivilant to 'Sh%tload'. (maybe a Decadump?)

It can't refer to a Fluid ounce, as a Fluid Ounce is a Volume, as it a cubic inch. Dividing a volume by a volume only works in ratios and has nothing to do with Specific Gravity.
 
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