Mold

Questions about Making Your Own Lures

Mold

Postby bassfighter1 » Tue Aug 11, 2015 2:37 pm

To Larry Or Mike,I Made A One Piece Mold From HS3 Two Days Ago And Today I Touched It And One Side Is Cured And The Other Side Is Kinda Gooey,Do I Need To Set The Mold In A Heated Area.
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Re: Mold

Postby Fomen38 » Tue Aug 11, 2015 5:28 pm

I know I'm not Larry or Mike, but I have poured lots of silicon molds, so I definitely have some experience. Your mold should have been cured a LONG time ago, like within 24 hours MAX after mixing and pouring. I had this happen to me one time. I tried using old silicon rubber (about 1.5 years old), where the silicon had settled and separated. I mixed it well, then added my catalyst, but it never would cure. So there are a couple of scenarios that are potentially causing your problem:

1. You're not fully mixing the silicon and the catalyst. It has a really long pot life, so you don't have to be in a hurry to mix and pour. You won't even see signs of it curing for 2 to 3 hours after pouring. Placing it in a warm place/environment will definitely expedite the process. Make sure you mix them in a clear container, so you can see if there's any unmixed silicon rubber clinging to the side of the container. Degass the silicon if you have a vacuum chamber. It makes a huge difference in the quality of the final product (bubbles). The HS3 turns pink when mixed. If you're having trouble distinguishing between the pink catalyst, and the white rubber when you're mixing it, add a tiny amount of red Alumilite dye (less than a drop) to the mix. This will make the color change more drastic, and you will definitely be able to tell if all the components have been fully incorporated.

2. Your silicon is old, and it has separated. Silicon "cures" via a chemical reaction between the silicon rubber and the catalyst. So heat will definitely expedite the curing process, but cooler temps won't inhibit it from happening. Now I'm not saying mixing it in the snow, and letting it cure in your freezer is a good idea, but I don't think that heat is an issue with your curing problem. I only mentioned the temperatures because you seemed to question if it was the temperature of the room that might be the cause of the product not curing. I can say with a level of confidence, that's probably not what the problem is. If your silicon is old, and has separated, there is a VERY easy way to tell. Take a stick that is long enough to reach the bottom of the plastic jug that the silicon rubber is in. Stick it down to the bottom, and gently stir it for 5 or 10 seconds. Pull it up, and if you can see there is some thicker material clumped up on the bottom of the stick, and there is thinner material kind of oozing over the top of it and dripping around it, then your silicon is old and it has separated. GET RID OF IT!

3. Your mix ratios of catalyst to silicon rubber are off. HS3 uses a 10:1 mix ratio. 100 grams of silicon should be mixed with 10 grams of catalyst. But if your ratios are off, it's due to you not using enough catalyst. It's not due to you using too much. You can't "eyeball" the amounts, or mix by volume. It MUST be mixed by weight, and it must be as close to 10:1 ratio as possible. It's important to use a quality digital scale. They aren't expensive. You can buy a decent one on Amazon for $15-$20.

So there you have it. It's one of those 3 scenarios that's causing your problem. Good luck amigo.

Scott
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Re: Mold

Postby bassfighter1 » Tue Aug 11, 2015 6:42 pm

Thanks Scott,This Is The First Time This Has Happened,I Bought The HS3 Three Days Ago,Hopefully It Will Cure Completely
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Re: Mold

Postby aka anglinarcher » Tue Aug 11, 2015 7:53 pm

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. :lol: 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.
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Re: Mold

Postby bassfighter1 » Tue Aug 11, 2015 8:03 pm

Hello AA,Yes The Gooeyness Is Near The Mold Box,I Just Cut From A Cardboard Box, Would It Be Safe To Put In Microwave To Finish Curing.
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Re: Mold

Postby aka anglinarcher » Tue Aug 11, 2015 8:26 pm

It is possible that it was a wax on the box that caused the problem. It is doubtful that heating it will fix it. IF I were to try, I would put a pan of water into an oven and put the two in the oven at 200 degrees for two or three hours. Humidity and heat speed up the cure..... but...... if it is a contaminate it won't cure, it must be removed. You can mix a small amount and "paint it" over the spot and sometimes that will be sufficient to cure it.

Give the oven a try first then if it doesn't work, ...........
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