• Tutorial - How to make a Silicone Mold and Resin/Plastic Castings

    If you find this boring then blame old Kytey

    These photos were all mocked up using using already finished components.

    First thing to do is find a flat, non-porous, base (I'm using the glass of a cheap photo frame. Perspex is ideal) and place it on a perfectly level surface (check in both directions).



    Place the items (Masters) on the base. I use a non-permanent adhesive to secure them from moving (double-sided tape in this case)



    Now comes the Lego bit (KEN!!!)

    Build a retaining wall around the masters to contain the liquid silicone. This can be made out of any non-porous material such as modelling clay etc. I always use Lego bricks as they are totally re-useable and it's so easy to make walls of any size.



    Then mix up the silicone moulding compound. All of the ones that I have used are mixed 9:1 by weight.



    I usually pour the required amount of silicone into a disposable plastic beaker, then place it on a set of digital scales (Yes I use the kitchen scales, but don't tell the Base Commander), poor in the accelerator, mix it until it has a uniform colour, leave to stand for about 10 minutes (or use a vacuum chamber), and then poor over the masters. Be aware that this will seep through the walls slightly, if you are using Lego, so you need to have about a couple of inches of clear space around the sides.



    Leave this to cure, at least over night, or preferably for 24 hrs.



    Once the silicone has cured remove the Lego bricks. This is another reason why I like them, because they are so easy to break away one at a time. This will leave you with a solid block of silicone like so:



    Gently prise this from the base and turn over to reveal the masters.



    Don't be surprised if the silicone has seeped under the masters. Just take a very sharp modelling knife and carefully cut as close to the edge as you can. Be careful to aviod going beyond the edge of the masters and damaging the mold.



    Now flex the mold and carefully remove the masters to leave the mold ready for casting. A little trimming of any excess silicone may be require or desired here.

    When you are ready to start casting, place the mould on a flat and completely level surface.

    Then mix the casting compound.



    This is a new liquid plastic resin compound that is mixed 1:1 and pours like water. You have 2 minutes working time to mix it and poor into the mold.



    After only 10 minutes (much longer for fibreglass resin) the plastic has cured and can be removed from the mold.



    Hey presto! You now have some lovely light weight plastic casting that is extremely strong...



    ...and very flexable. Now all you need to do is clean it up and away you go.

    Any questions?
    This article was originally published in forum thread: Tutorial - How to make a Silicone Mold and Resin/Plastic Castings started by tonyc206 View original post
  • Donations


    If you like our website and want to give something back, you can make a donation.

    Please select a preferred amount of the donation, and then click the poster image below.

    Donation Amount