Hi Bass, sad to hear you are having problems.
Scott is not far off, but I don't totally agree when it comes to HS3. I have used a lot of the HS2 and HS3 and once had your issue, so perhaps I can help.
First, if you bought it 3 days ago, it is most likely just fine. That does not mean it has not separated, it can, but if you stir it well it will be fine. I suspect you bought the 1 pound container locally, so it is easy to open the top and stir it well with a flat stick, like an ice cream stick or craft stick. Mix it until there are no clumps left, then mix some more. YOU DO NOT NEED TO TOSS it.
Second, it will start to cure much faster then 2 to three hours so you can't mix, take a nap, then come back and pour.
Still, you don't need to hurry either. The link to cure times and pot life is as follows:
http://www.alumilite.com/store/p/921-Al ... gth-3.aspx I find that the 45 minutes open time (mixed pot life) is pretty accurate.
Third, exact measurements are not as important as suggested. Yes, I use a scale, and the one you can get at Harbor Freight is just fine. I got my current scale at Cabalas and it is a reloader quality and I find no improvement in results. You can also use the included dipper/scoop, but I find the scale from Harbor Freight is so easy to use. Of course the one sold by Alumilite is excellent as well. If in doubt, add a little extra catalyst.
Forth, assuming you got close on the ratios, you mixed the silicone well to undo separation, you probably failed to mix the catalyst into the silicone sufficiently. That is a possibility, but not my first guess. Still.......if all of the mold was sticky, this would be my guess.
One last possibility exist that I can think of. This might be the most likely option. You mention that one side is cured and the other is "Kinda Gooey". Was the "gooey" side against the "mold box"? Certain contaminates prevent the silicone from reacting properly. This can cause the one side to cure but the side against the contaminate to remain uncured. If you slice into the uncured mold, is it just a fairly thin layer that did not cure? If so, you can slice off the uncured layer and get a new mold box, then pour a new mix against it to fill out the mold and complete the pour. The HS3 is a Tin base silicone, so it is not negatively impacted by most clays or substrates, but I still find some things, like some clays, even some oils, can cause issues.
The following is part of the technical data sheet you can download as well.
Mix Instructions: The proper mix ratio for Alumilite’s High Strength 2 & 3 liquid silicones is 10:1 by weight. Use an accurate scale and measure out 10 parts of base to 1 part catalyst by wt. If you are using the 1 lb kit, use the 1 oz cups and scoop provided in the kit. Measure 1 SCOOP OF CATALYST for every 2 FLUID OUNCES OF BASE. Follow the instruction sheet provided with the kit. Read all MSDS and cautions on the bottle prior to using.