Silicone & FuseFX

Silicone & FuseFX

What is the NUMBER ONE RULE of silicone?

Test, test, TEST!

Platinum silicone* is a wonderful, amazing, versatile material. You can cast it in a mold, you can thicken it and build it up over a form, you can thin it to let it flow into a smooth, glass-like surface. It's relatively inert and non-toxic, wonderfully translucent, and a little tends to go a long way.

But aside from being a bit messy it has one major flaw...... inhibition.

No, your silicone is not shy. Silicone is normally comprised of a liquid A part and a liquid B part. When mixed together a chemical reaction occurs which solidifies the viscous fluid into the stretchy, rubbery silicone we know and love. Inhibition then, is when something (usually a foreign chemical in the mix) prevents the proper reaction between the A & B parts and keeps the silicone from solidifying. In other words - a big goopy mess.
The extremely frustrating thing about inhibition is it seems to be caused by extremely random things! Something as simple as wearing latex rubber gloves (latex and silicone are mortal enemies!) while handling and mixing your silicone will cause inhibition.

Which is why it's extremely important to ALWAYS DO A TEST FIRST!

Need to wash off your silicone pieces before painting/adding further detail etc? Test that soap first! Aloe inhibits silicone (see? Told you it was random) and guess what? A lot of soaps have aloe in them.

How do you do a test? While wearing vinyl or nitrile gloves (which don't cause inhibition) wash out a small mixing cup with the soap you are thinking of using. Rinse well. Then mix a small batch of silicone in the cup. It doesn't have to be big at all - less that a teaspoon in total will more than suffice. Leave it for the recommended curing time (which will vary depending on the brand and type of silicone you are using). When you return, give it a poke. Has it solidified? Yes? Great - go ahead and use that soap! No? Then something in the soap is causing inhibition and you need to switch brands.

You need to do a test every time you add an untested substance into your process. Just because one type of soap works doesn't mean all of them will. Ditto with glues, if you are attaching foam pieces together before you coat them in silicone.

T'is a far, FAR better thing to sacrifice a teaspoon or two of silicone then forge on ahead and potentially ruin ALL your expensive silicone and all the time and effort you have put into your piece.

if you learn nothing else about silicone your mantra** should always be - TEST! TEST! TEST!

* This article talks mainly about Platinum-based silicones. Tin-based silicones are less prone to inhibition but have their own unique challenges.

** A mantra which, by the way, will serve you very well for a lot of non-silicone stuff too! Scientist-like habits can lead you to great artistic triumphs!

What is  the difference between Tin and Platinum Silicone?

Tin Silicones are high-tear silicone rubbers that are known as the “work horse” of the industry because of their performance and economy. Tin cured silicone molds are used for casting wax, gypsum, polymer modifed gypsum, etc. but are best known for standing up to production casting of urethane, epoxy and polyester resins. They are also known as “condensation-cure” silicone. Platinum silicones exhibit the lowest long-term shrinkage and have the longest library life of all mold rubbers. While good for making molds for casting a variety of materials, platinums also have application and physical properties that other rubbers do not. They are also used for making prosthetic and orthotic devices, skin safe appliances and effects, etc. Platinum silicones are also known as “addition-cure” silicones.

What is "inhibition"?

Platinum silicones are very sensitive to certain compounds which may prevent the silicone from “curing,” or turning solid. This is called inhibition. The most common inhibitor of platinum silicone is sulfur compounds, which is present in latex, natural rubber, neoprene, and wood. Make sure your work gloves are vinyl or nitrile.

Help! My FuseFX paint is not setting!

1) Make sure the piece you are painting is made platinum silicone. 2) If the piece being painted is made of tin silicone, make sure the surface is primed with a layer of BondFX Silicone primer. 3) Make sure the surface is completely clean. We recommend cleaning the surface with isopropyl alcohol (rubbing alcohol). 4) Make sure you have mixed Part A and the paint colour in the ratio of 1:1.

How do I know if my FuseFX product is expired?

FuseFX Silicone Pigments, as well as Smoothie concentrate have an indefinite shelf life. Once mixed, Smoothie is still useable as long as no mold develops.
FuseFX Silicone paints have a 3 year shelf life from the time of manufacture. Paints may work after 3 years, but it is not guaranteed.
FuseFX Royal Jel-E silicone mold release should be used within 3 years of purchase. While Royal Jel-E doesn’t truly ‘expire’, it becomes less effective over time and may need more coats to ensure a smooth release after three years.

Can I use FuseFX to paint a vinyl/latex/unidentified "rubber" ____?

No, FuseFX paints may only be applied to painting pieces made with platinum silicone. The paint will not adhere to the surface, or may not cure at all. The only exception is that FuseFX CAN be used to paint tin silicone but ONLY if the piece is first primed with FuseFX's BondFX primer.

What is the difference between FuseFX intrinsic colours (pigments) and extrinsic colours (paints)?

Intrinsic colours (pigments) include the S, SFX, and BC series pigments. These products come in a single bottle and are meant to be mixed into a batch of uncured silicone to tint the entire batch a uniform colour. Extrinsic colours (paints) include the M, F, and LY series paints. These come in 2-part "kits" - an uncoloured, 'Part A', catalyst, and the coloured 'Part B'. They are meant to be mixed 1a:1b and then applied to the surface of a cured, cleaned, silicone piece to paint it.

In this package of FuseFX there is a "Part A" but where is the "Part B" mentioned in the instructions?

With all FuseFX 2-part products (the F, LY, and M-series paints) the "Part B" is the coloured bottle. To activate the product you need to mix it 1:1 with the included Part A.

Can I add more/less Part A to make the mixture more/less transparent?

NO - you MUST mix the Part A in a 50:50 ratio with the Part B otherwise the product will NOT cure. You can mix these by eye, as long as the ratio is close to 50:50 but other ratios will not work.

To make a colour more transparent you can thin the mixed paint with an appropriate solvent (Toluene, Xylene, or Naptha) or you can add M/F-110 Clear PART B to the coloured Part B of your choice BEFORE adding enough Part A to equal the two B's _combined_. For example you might mix 1 part M/F-110 Part B to 1 part F-230 Darkest Brown and then add 2 PARTS of Part A to activate the mixture for painting.

Can I airbrush silicone?

Yes! You will need an appropriate silicone solvent (such as Toluene, Xylene, or Naptha).

To airbrush FuseFX: mix the FuseFX paint as normal (50:50 Part A and the coloured Part B) then dilute the mixture with 1.5-2 parts of solvent and continue to mix until smooth.

Spray at approximately 15 PSI.

What solvents can I use to thin silicone?

Mixed silicone can be thinned with Toluene, Xylene, or Naptha. These solvents are not always sold under these names (often they are sold as odorless paint thinner). It is recommended to do a test before using a new brand or type of odorless paint thinner to make sure it contains the correct solvent and does not contain other fillers which may inhibit platinum silicones. Alternately you can get a dedicated silicone solvent such as Smooth-On's NOVOCS Glossy or NOVOCS Matte thinner.

BEFORE mixing you can purchase a silicone thinner add-in from a supplier such as Smooth-On. Follow directions carefully as too much thinner can inhibit the mix.

Are FuseFX products skin safe?

Yes ... and No.

For FuseFX paints and pigments the products are skin safe once they have cured. While the products are in an uncured state, however, you should wear vinyl or nitrile gloves (NOT latex) while handling the product.

Smoothie and Royal Jel-E should be used while wearing vinyl or nitrile gloves.

How should I prepare a silicone piece for painting?

You will have the best result by painting a silicone piece fresh out of its mold. In this case simply wash the piece thoroughly with soap and warm water to remove any mold release residue then dry the piece with a lint free cloth or lint free tisues. If you are trying to paint an older piece that has been used or been on display it is best to wash it thoroughly with soap and water, scrubbing gently or even wet sanding with 400 grit sandpaper, then wipe it down with a lint free tissue or cloth and isopropyl alcohol or a silicone appropriate solvent (see the Solvent question in this FAQ for some suggestions). You may wish to apply a thin layer of BondFX as a primer before painting. Older pieces are prone to paint delamination (see previous FAQ question on "I have an older silicone piece - can I still paint it with FuseFX?" for more information). If you know you will not have a chance to paint your piece right away after demolding it is best to either place your piece in a sealed plastic bag, plastic tote, or wrap it securely in plastic wrap. This will protect your piece from collecting dust and you should be able to paint the piece at a later date with no problem.

How much FuseFX paint do I need for my project?

30g of catalyzed F-series paint can cover approximately 12sq ft if stippled in a thin layer. M and LY-series paints will go even further as they are typically painted sparingly to create a realistic skin look instead of applied as a continous layer. For the S and BC pigments one 30g bottle can tint over 3,300g of catalyzed silicone (or approx. 7.2 pounds or 116.4 oz). The 500g bottle can tint over 100,000g or 100 kilos (approx. 27 gallons or 220 pounds) or more depending on the softness of the silicone. See the video below on using S-series pigments for tips on calculating the amount of pigment needed for a project.

If I make a mistake while painting can I fix it?

YES! As long as the paint has not yet cured you can simply wipe it off with a lint free tissue and a bit of isopropyl alcohol.

Once the paint has cured however, it permanently bonds to the piece and will have to be cut off to be removed.