Using “Plastex” for molding?

Craft & Design
Using “Plastex” for molding?

PlastexA Make reader is wondering about using “Plastex” – “Have you heard of ‘Plastex’? I’m interested in the home casting materials of plastex and friendly plastic – the former, in particular, anecdotally seems like it make have enough structural integrity to actually make useful items from and not just use it for gap-filling repair work as it is sold, yet seems much easier to work with than the entry-bar for other types of molding. I have not experimented with these items on my ‘to do’ list. (actually I did use friendly plastic as a kid – it melts however at high temperatures which could be a liability).” Have any Makers out there used this stuff? I’ve only see it here and here.

10 thoughts on “Using “Plastex” for molding?

  1. waylan says:

    Thats a good question. Anyone know how well vinyl dye works on the stuff?

  2. travis j icorcoran says:

    Lots of hobbyists, model makers, architects and special effects folks use various silicone, room-temperature vulcanizing, etc. casting technologies.

    There are a few different technologies on the market, and they all work.

    Using the stuff isn’t super hard, but there are a few little tricks, like making a break-away mould, getting the parting line right so you can remove your item after casting, getting the surface detail to show, etc.

    There’s a good video (I’ve watched it a few times) called
    “Reproduce Almost Anything” with Ben Ridge.

    You can buy it at, or you can rent it from
    Technical Video Rental.


    (Note: I am affiliated with TVR).

  3. rodaniel says:

    I haven’t used it myself, but Magic Sculp sure seems promising. The Gallery on the manufacturer’s website shows some incredible stuff.

  4. TeutonicLove says:

    Alumilite really doesn’t work too well and will prove to be quite frustrating for the beginning user. I found in my experiences with it that it tends to not mix well enough to produce a consistent casting. The stuff that I found to work the best were the various Smooth-On products, especially C-1508. Smooth-on also makes a number of molding silicones, some of which have amazing tear strengths and high detail replication.

    To achieve a high caliber casting it’s also necessary that you use a pressure pot to insure a gap-free end product.

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