High Strength 1

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Use High Strength 1, a tin-based silicone mold making rubber, when your mold requires a little more stiffness but still need exceptional tear strength.

  • Doesn’t require degassing, but recommend when possible
  • Great for one- or two-piece molds that require stiff mold properties
  • Use Rubber to Rubber mold release or petroleum jelly when making 2-piece molds

Prior to using product, please read all Technical Data, Safety Data, and Instruction sheets linked below.

$33.99 - $199.99
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Technical Specifications

High Strength 1
Mix Ratio:
10:1 by weight
Pot Life:
45 minutes
Demold Time (100 gram mass):
12-18 hours
Mixed Viscosity (cps) at 130º F:
Specific Gravity:
Linear Shrinkage:
Shore Hardness (ASTM D2240):
38 A
Tear Strength (ppi):
Elongation (in./in.):
Tensile Strength (ASTM D638, psi):
Temperature Resistance:
-67º to 395º F

More Information

Prior to using product, please read all Technical Data, Safety Data, and Instruction sheets linked below.


  • 5
    Update to my previous review

    Posted by MARY TOTZKE on Oct 13th 2021

    Customer Service reached out to me and acknowledged they were having some kind of production issues. She sent me replacement product, and it works like it used to. Now I just wish they could make it pink like before. The liquid is clear, which makes it difficult to tell whether you have mixed it completely. I am adding one of their colored powders to the clear liquid to make it pink.

  • 2
    Not the same stuff

    Posted by Unknown on Sep 20th 2021

    Not sure what Alumilite is doing to their stuff, but its definitely not good as before. This batch of high Strength 1 is way thicker than the high Strength 1 I've always used. You can't even hardly pour it after you mix it. Sadly Alumilite products are going down hill.

  • 2
    This used to be perfect

    Posted by MARY TOTZKE on Sep 14th 2021

    I have been using this product for over 5 years and it's always been perfect. However, the last two batches I received are not the same as usual. I purchased one batch in March 2021 but had to wait a couple of months before I could use it. It was very thick and hard to de-gas. I chalked it up to letting it sit around for too long. Ordered another batch a few weeks ago, and it is even worse! Four of the 11 molds I poured are ruined - and I only get one chance to make a mold. I compared it to my "older" batch, and this recent batch is even thicker. I've made 200+ molds using the product, so it is not operator error. Something is wrong with this product.

  • 4
    High strength mold

    Posted by Dale Fischer on Jul 17th 2021

    The stuff started to kick off faster than I had anticipated it would. So, degassing it did not work the best. Still, it worked out well. Just got to start using it now.