How To Make Your Own Silicone Soap Mold Liners Tutorial

How To Make Your Own Silicone Soap Mold Liners Tutorial

ou can make your own silicone liners for your soap moulds, all
you need is some RTV silicone (easily sourced from the internet or
locally) and some simple supplies you can usually find around the
house. Silicone is not a cheap material, so making your own can
save you labor cost , as well as make soaping easier and more fun
without having to line your moulds all the time! You can also pour
your liners onto cool textures to make all sorts of uniquely
textured soaps. Try pouring on engraved plaster to create a liner
custom made with your logo. It takes a bit of patience, but is
certainly not too hard for anyone to accomplish in a weekend.

Silicone is the only material that will adhere to silicone. It does not
“glue” the pieces together, it chemically welds them, which means
that when joining two pieces of silicone with silicone they become
chemically and physically the same object. This is like metal
welding, only with silicone, so the finished product is just as
strong as one that was made with one pour. There isnt much
difference to the end user having a liner made in one pour vs. one
welded from pieces, although they take longer to make, but as
long as the pieced one is put together with care and attention to
detail, they are just as good. Welded silicone liners are strong and
practical for those wanting to make liners and save some money.

**For even cheaper liners, you could try Polyurethane Rubber.
Polyurethane is not ”self-releasing“ like silicone, so will require
mould release agents like food grade silicone and wax, but savings
of up to 50% off the cost of silicone can be realized. The pros for
this material are its much cheaper than silicone, firm but flexible
material, and very durable and much longer lasting than silicone.
The cons are that when molding soap the mould will need a
release agent like food grade silicone or wax, so its a bit more
work than silicone.



Planning the layout and height of your liner,
and then arrange into one or two flat areas as in the diagram. Remember, silicone is expensive,
measure twice and pour/cut once!

Determining the amount of silicone for your mould
I would suggest a liner thickness of 3mm for the most cost
effective use of your silicone as well as not taking up too much
space in your mould, while retaining adequate strength.
After you have determined the surface area you will need to cover
with silicone (the internal surface area), ensure the measurements
are in cm, and determine the total surface area in cm squared. If
you want a 0.3cm thick mould (3mm), multiply the surface area by
the thickness of the liner to get the volume of silicone in cm cubed,
or ccs, or mls. This volume is equivalent to the material in weight
(as 1cc/ml of silicone is approximately 1g of silicone), so for
measurement purposes convert the volume to weight.

Here is an example to illustrate:

Liner surface area (as contained in the frame) is 39x32cm = 1,248cm2

1,248cm2 x 0.3cm(thick) = 374.4ml (or ccs) = 375g

With the average cost of silicone at $0.05/g = $18.75

As you can see increasing the thickness will greatly
increase the price of the liner:

1,248cm2 x 0.5cm(thick) = 624ml (or ccs) = 624g silicone. = $31.20

1,248cm2 x 1cm(thick) = 1,248ml (or ccs) = 1,248g silicone. = $62.40


  • Long wooden battens or strips of cardboard or any other straight objects to make frames.
  • Stirring stick/spatula, plastic tub, and gloves.
  • RTV Silicone (I would suggest starting with about 1kg for cost
    effectiveness and for just enough volume without huge
    investment. If you plan to make many liners or if you have large
    liners, 5kg packages are the most economical and cost effective of
    the smaller packages, ranging from $200 to $250AUD)

Desirable properties (guide only):

Low to medium viscosity (45,000 cps or less) for
smooth pouring, medium cure time (min about 6 hours
to full cure and 30min pot life to allow working time,
real cure time is usually half of advertised cure time),
and Shore A hardness of 25 or greater the firmer the
silicone (Shore A of 35-50) the thinner the liner can be
while retaining the same strength and support (as long
as the other qualities are still present).

Australian Resources and Suggestions:

Webmasters Note: there are many
similar products available in different countries, I currently reside in the
USA and upon searching for similar products available both online and in my
local area via Google, I did not find it hard to locate these products. If
you need help please visit our forum and pose any
question you may wish to ask]


Adelaide Molding and Casting


(made by Barnes Silicone)

Maximould, M4503, Ultrasil.

Barnes Silicone (


Use caution if you choose to use
Pinky Silicone, as this silicone must be molded in
about 6minutes, which may not be enough time to
pour/spread your liner, otherwise its the best silicone
so may be worth a try! Tufsil 25, Maximould, M4503,

Solid Solutions

Suggestions (Tin Catalyzed): Solid Mould 500,
Polytek TinSil 70-30.


Check your local Fiberglass and Mould Making
Supplies Store; many carry RTV silicone and the
Barnes range of products (their website lists
stores that supply their silicone). Just look up
“fiberglass” or “molding and casting” in the
yellow pages.


    • Layout the batons into the surface
      area rectangles required for
      your size liner, to contain/mould the silicone. Be sure to use a
      right angle tool or the corner of a sheet of paper to square your


    • Tape around the edges of your walls to
      prevent any silicone leaking out.
    • Ensure the surface you are pouring
      onto is clean. You can pour
      onto any surface, including cool textures (bubble wrap, sandpaper,
      needle point grid, ect.. beware of fabrics or carpet, silicone can
      soak in and be hard to get out!).


      You can use the side of the silicone that is touching the
      surface as the inner or outer part of your liner depending on which
      you prefer. Sometimes it is better to pour your liner onto a slightly
      textured surface like paper or MDF and use the side that contacts
      the MDF or paper as the outer side of your liner, because it will
      not grip onto your outer wooden mould when inserting.

    • Mix your silicone as per the
      manufactures guidelines (search for
      pouring silicone and the “bombs away” method on the internet for
      some really good videos. Tap Plastics makes great instructional
      videos). Pour into your frame using the “bombs away” method to
      reduce air bubbles. The bombs away method is essentially pouring
      a very thin stream from a height to stretch and pop any bubbles that
      were trapped in the silicone during mixing. Using a plastic spatula
      spread the silicone into the corners and even-out thin or thick


    • Blow across the silicone with a hair
      drier set to cool and with an
      air funnel/straightening attachment to make a concentrated blast,
      or just blow across the top of the silicone with your mouth, to pop
      any remaining bubbles (just be careful not to accidentally spit on it
      or hyperventilate lol).
    • Cover your frame with a board or other
      stiff cover if you are
      worried about lint or pets/kids getting into it while it hardens.
      Allow curing for the recommended time, heat generally speeds up
      the cure (as the reaction is endothermic), so a blast with a hair
      drier, heater or keeping it in a warn room will quicken the process.
      Do not use a heat gun or flame on the silicone as this is TOO hot.
      To clean up your mix pot and spoon, just let the silicone cure and
      peal off, its really easy to clean! Or you can put the silicone pot
      with the extra silicone on the sides in the freezer to prevent it from
      curing for about 1-2 days, and use it later to join/weld your liner


    • When dry, peal off the frame and
      surface. Trim/slice the silicone
      sides to fit into your mould.




    • Mix a small batch of silicone (about
      10g is enough) or get the
      remainder you saved from the freezer and apply to the edges of
      your liner sides and weld together supported inside your wooden
      mould (you may need blocks or other objects to hold your sides up
      from the inside as well). Wipe away excess, and allow curing.
      Youre done!silicone8


      It is less messy, easier, and fills gaps better, putting the
      silicone on the thin edges of your sides and putting in place, rather
      than smearing onto the receiving surface.

Enjoy Your Liners!


(Please do not reproduce, distribute or sell without
permission information is given in good will
and we are not responsible for damages or losses resulting from the use of
our instructions and tips)

Author: Kaseen Coo

soap moulds