Problem with Alumilite Mold material

Resin jewelry making resin art supplies Forums Molds and moldmaking Problem with Alumilite Mold material

This topic contains 9 replies, has 2 voices, and was last updated by  Myleigh O’Neill 3 months, 3 weeks ago.

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  • #5421 Reply


    Hello! Happy to find this forum! I have had an issue driving me nuts. I actually was successful in the past, but when I went larger had the issue.

    I used the Amazing Mold Rubber to make some molds. I then used ice resin and the molds were small, but it worked and they cured fine.

    Maybe a year or more later decided to make some more molds. I used the entire amount in the package of the amazing mold rubber to make what came out to be really nice molds! Then, when casting the pieces do not cure and come out oily. I thought maybe the molds were not cured enough so waited weeks. Tried a couple types of resin (ice resin and little windows resin) and neither will cure right.

    Now I have noticed I don’t see this specific type of mold rubber (amazing mold rubber) for sale. But I do see a couple others from alumilite for sale here. I am wondering if I used the cheaper stuff they have and what is the chemical conflict? Anyone? Thanks in advance so much for your help. I spent over $50 and made these molds I cannot use it seems! a real bummer. I also contacted alumilite about their product with no reply. blah


  • #5422 Reply

    Katherine Swift

    HI Dawn,

    Let me see what I can find out.

  • #5425 Reply

    Katherine Swift

    Hi Dawn,

    I have spoken with my tech support contact at the company. She is sorry to hear you didn’t receive a response about your question and is happy to work with you directly. Her name is Carol and her direct email is world [at] alumilite (dot) com. In the meantime, here are a couple of her thoughts:

    There is approximately 6-8 months shelf life on silicone. The fact the mold cured is good and it should be alright, but a test is in order. I would like to test the molds myself to see if it is a problem with the silicone or the resin used.

  • #5429 Reply


    Thanks so much! Well I did order it from amazon so it would not have been too old product. I also used a plastic card box top, the thin clear plastic to create the mold. I used some glass cabochons with e6000, which I have thought maybe the glue fumes contaminated it? I did wait a day or so for the mold base to dry before pouring the silicone. I will gladly send you one to try! thanks for your help.

  • #6084 Reply


    I came to this forum hoping to find answers, because I am having the exact same problem! I purchased Amazing Mold Rubber (High Strength Liquid Mold Making Rubber) by Alumilite from a local store and made some small molds of beads. The molds seemed to set up just fine. But when I poured Ice Resin into them, the surface of the resin was sticky and tacky after demolding and remained sticky even after curing for days. I know it’s not an issue with my resin, because I poured some of the same batch into bezels and another silicone mold, and it hardened normally. I tried it again without adding any powders or colors to the resin, and it still is sticky, and again, the same batch of resin hardened normally in other molds. Perhaps Ice Resin doesn’t go well with this type of mold making material, or perhaps it has gone bad?

    • #6096 Reply

      Katherine Swift

      I emailed the manufacturer for help and this was their suggestion:

      Every once and while we here of this issue, rarely but we don’t run into it in shop. The only thing we can attribute it to is that possibly there could be some left over uncured molecules on the surface of the mold. That may interfere with the first couple of castings leaving you with a tacky/sticky feel to your pieces. Wash the mold out with some rubbing alcohol or dish soap. Make sure the mold is completely DRY before pouring resin into the mold, urethanes or epoxy resins do not like moisture (humidity) or anything with water in it.

  • #7411 Reply


    Interesting – I just had the same thing happen to me with some Alumilite #3 that I bought from Amazon. I posted on a different thread through this site. Maybe there was an off batch sent to Amazon? I am trying to wash mine, but I don’t think I will get a nice smooth finish that allows for the super clean shine on the finished resin piece. Next batch I buy will be from here!
    I’ll let you know if my next castings turn out smoother.

    • #7420 Reply

      Katherine Swift

      We are very fussy about making sure we rotate stock and sell it as ‘fresh’ as possible.

      Let us know how this works out for you.

  • #7425 Reply


    The washing in soaping water did get the greasy/oily feel off of the molds, but they still are not casting items with the shine I was hoping for. Guess I’m starting over.

  • #36370 Reply

    Myleigh O’Neill

    I have had this problem as well. I washed, dried, alcohol rubbed, mold released, powdered, used all types of things, and I still can not stop that sticky residue! Until I tried soaking my resin pieces in warm water (a wash of sorts) and then glazed over it with either clear nail polish or a brush and resin (which wastes the brush/sponge). I want to keep from wasting and be able to use my molds I’ve made for full production.

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