Why Doesn't My Silicone Paint Stick?

Original Post here ~ Why Doesn't My Silicone Paint Stick?

Let’s talk about why paint won’t stick to silicone.

I’ll start off by saying, “Every Silicone Artist is going to have their paint not stick,  more times than you’re expecting.” It is all part of the job. A Baker deals with flour on his shirt, a Chimney Sweeper deals with soot on his face, and a Silicone Artist deals with paint not sticking. In fact, it happens so often that I know many people who would never pour and sell silicone kits to others because they just can’t deal with their customers saying ‘ my paint is not sticking’.

So, if your paint doesn’t stick, you are not alone. But if you are planning on painting more than one doll, then you are going to have to learn how to battle and conquer this for yourself.  And that is why I am going to break down a troubleshooting list for painters to go through to help when your paint doesn’t stick.

*this article is written for PLATINUM-based silicone. NOT FOR TIN-based! Make sure your kit and all silicone supplies are Platinum-based. Lots of knock-offs and Chinese silicone and factory manufactured silicone dolls are tin-based to keep costs down. If your silicone doll was inexpensive it’s a good indication it is most likely poured in TIN.

1.) Did you properly wash your silicone piece? Most of all the Silicone Castor/Pourers I know will always go the extra mile and effort to thoroughly clean their kits before sending them off to their customers. When a silicone doll/piece is being poured, Pourers will spray/coat a release mold into their molds to prevent the silicone from bonding to it. This release agent remains on each pulled piece and the Pourer will then scrub with soap and solvents to wash off the release so it is easier for the Painter to paint. Sometimes the release agent lingers or spots are missed on a prepped kit and it is the responsibility of each Painter to go through the process of re-cleaning and prepping their piece before painting. Maybe even twice.

This is how I clean my pieces: Scrub down each piece with Dawn dish Soap, hot, hot water, and a soft toothbrush. You can even leave your piece in soapy water overnight and all the dirt will float to the top! RINSE THOROUGHLY (soap is also a release agent)!!!!  Then I wipe down with 99% isopropyl alcohol and will do a pass of NOVOC gloss (these two chemicals can be done in either order). These solvents dissolve any soap residue or any remaining oils. Now the piece is ready to paint.

*some use a different method. If unsure you can ask the Pourer what they recommend.

*some also use matting powder on their kit before shipping it to take away the stickiness. This also needs to be washed off! Go ahead and read my Blog Post ‘Prepping Silicone Kits’.

 2.) Is your paint old? Manufacturers say most Silicone ( we are talking mainly about Psycho Paint Silicone in this post) have a shelf life of about a year. Here are the SmoothOn recommendations for Psycho Paint:

This being said I’ve had my paints sit on a shelf longer than the recommended shelf life and they were still great. So, if your silicone paints have been sitting for a while just do a little test (you’re going to hear me say ‘TEST’ a lot in this post!) of mixing A and B together in a pot or palette and see if it cures. If it does… they should be still good.

3.) Was your paint properly mixed? This area can have a few mistakes. Most all Platinum Silicones I know of are mixed by adding equal amounts by volume or weight of Part A to Silicone Part B. When mixing your Silicone you need to be careful to be accurate. A teaspoon of Part A needs a teaspoon of Part B.  250grams of Part A needs 250grams of Part B. 1oz of Part A needs 1oz of Part B… to catalyze properly. This is important.

Here are a few scenarios that have happened where mixing wasn’t done properly (and it happens to everyone and more often than you think):

• Improper amount (volume or weight) of A to B (or vice versa)

• Not carefully and clearly marking your bottles of A and B and mixing A and A together (or B and B together).

• Forgetting which Part you put into your pot and then mixing together the wrong Part to catalyze.

• Too much or the wrong thinner with your silicone. I’ve accidentally put my alcohol into my Silicone instead of my NOVOC (bottles looked the same.. try and get different color bottles or labels, lol) and then it was completely ruined. Recommended amounts of thinner are:

• Improper amount of pigment added to your silicone (if you’re not using a pre-mixed color). If you’re using a Psycho Paint base the recommendations of pigments are 2-5% of total weight of A and B TOGETHER. So you may be adding too much pigment to your Silicone. OR some pigments can be oily and if you don’t shake them well enough you just get the oil on the top and that can inhibit cure. Recommended amounts of pigment are:

4.) Did your piece touch something to inhibit the cure? Your reputable Pourer will NOT have anything in their workplace that will hurt the pieces they poured. They will go above and beyond not to have anything even NEAR their Silicone Pieces because they know that even the smell of these inhibitors could affect their Silicone.  Latex, Sulfer, Tin Silicone…. all of these will inhibit the cure of your Silicone. And all of these things are in many many things. Gloves, sponges, pacifiers, other dolls… etc. So when you opened your box and pulled out your kit was there anything it could have touched from that moment to painting it, that could have inhibited your kit…. even on your hands? Here are some materials that will cause Platinum Silicone Inhibition:

• Sulfur-based clay or gloves

• Tin-cured silicone rubbers

• Polyurethane rubbers

• Latex rubber

• Some paint products

• Some 3D printed plastic materials

• Bondo (and other polyester resin products)

• Amines, (ammonia)

* I give credit to Tom McLaughlin who says it perfectly, ‘ Platinum Silicone will not cure in the PRESENCE of these materials.’

5.) What are your sponges made of? This is HUGE! In the last year, more and more people are starting to paint silicone and they don’t realize that their sponges have latex in them. And I will say, it’s not their fault because some sponge brands are deceiving… because they say LATEX-FREE. But what is deceiving is there is both synthetic and natural latex… So the package may say Latex-free but that is because there is no SYNTHETIC Latex in them….. BUT NATURAL Latex can still be there. Some sponges even have lotions like Vitamin E or some other additive in them. So, ALWAYS, ALWAYS, ALWAYS, every time you get a new package of sponges, TEST THEM!!!! Even if you get them from a recommended silicone source, TEST THEM!!

Simple test: Mix Part A and Part B together in a pot and apply a nice size glob on a sponge (two sponges if you wanna make double sure). If it cures solid in the proper curing time, they are ok to use. If the silicone is gummy to the touch or when you stamp it, throw it out, they are BAD!

These are my favorite: (STILL TEST!)

 6.) What are your gloves made of? This one is the same as sponges!!! So many issues with gloves!!! It is very important to pay attention to because sometimes gloves will say latex-free but they may have something in them that will inhibit Silicone cure. Nitrile gloves are one of those gloves that you really need to watch out for because they may have sulfur in them to make them stronger than an average vinyl glove. A tell-tale sign is your silicone isn’t sticking to the back of the head but it is on the face. The spot where you cradle in your hands is the place where you will get inhibition. So what do I say???? ALWAYS, ALWAYS, ALWAYS, every time you get a new package of gloves or on EVERY glove, TEST THEM!!!!

Simple test: Mix Part A and Part B together in a pot and apply a nice size glob all over the glove and fingertips. If it cures solid in the proper curing time, they are ok to use (the silicone should just peel off and you’re able to use the glove again).

7.) Are you even wearing gloves? There are oils on your hand along with other transfers and those oils can inhibit the cure of silicone. OR it can even act as a barrier between the piece and your silicone paint so that the paint will cure but possibly can be rubbed off because it didn’t get a proper bond. Clean gloves or even Saran wrap (acting as a glove) is always recommended. I don’t like gloves so I will scrub my hands clean and use Cling-Wrap or Saran wrap as a glove between my hand and piece.

8.) What are your other materials made of? Brushes, palettes, other supplies.  What you are laying your piece on? Someone used a plastic table setting Mat for their work surface…. but when she applied silicone to it it wouldn’t cure. And it was affecting the cure of her paint because all her pieces were resting on it. Heartbreaking!!! What is touching your piece as it dries. Everything your silicone piece touches should be analyzed as to whether it could cause Silicone Inhibition (re-read Point 4 for materials that cause Inhibition)… Again, if you think it could be something specific, TEST IT!

9.) Have you heat-cured? This is a little hidden gem. Silicone can be very finicky about the temperature in the room. Too cold and it will NOT cure. And if cold for too long, it will just never cure. So if your room is too cold OR your paint isn’t curing in proper time OR you just want to hurry the process up, heat works like a gem! A regular hair dryer is great or a crafters heat gun. (i don’t recommend an oven). Here is the recommendations:

10.) What are the solvents you are using? The recommended thinner/solvent from me is Smooth On’s NOVOC Gloss (or Matte but I personally never use this). However, there are other solvents you can use to thin your silicone. I will make a list but AGAIN ….hahahaha.. you know it…. TEST!

Simple test:  STEP 1: Mix Part A and Part B together in a pot and add your chosen thinner. If it cures in the pot, its good.

STEP 2: Apply some of this thinned silicone to the unseen flange of your silicone kit or in a spot that will not be seen. Cure. If it cures, your good to go.

Please remember Point 3 about thinners. Too much can inhibit cure.

Here is a list of other Solvents: (please remember some are flammable and are not good for the lungs. Read directions first!)

Naptha, Colman Lighter Fluid, SAM Odorless Silicone Solvent, Odorless Paint Thinner, Mineral Spirits, Mona Lisa Thinner.

11.) What does your environment look like? Room Temperature; too hot, too cold? Is there Latex in the room? In the next room? You may think this is ridiculous but I went to a workshop years ago in a Reynolds Class (silicone pros) and they talked about how latex was in the next room and just passing from room to room was inhibiting cure. Silicone is SOO SOO finicky that you may not always know what the issue is other than it being a stubborn, traumatic teenager who is just NOT gonna listen!!!

So, what happens if 1 and all 11 of these things occur???? What can you do? Here are some of ‘my recommendations’ along with what others have found helpful:

First, find out what is causing the inhibition and fix it.

Second, your piece needs to be cleaned again. I will clean it, prep it, heat it, and then clean and prep it again. (soap, water, alcohol, NOVOC). Usually, this works just great and my paint will now stick. To make sure, I will do a tiny, thin test patch of CLEAR PartA and PartB and cure it with heat. And then see if I can rub it off. If it’s cured and not budging, you’re good to go.

Third, sometimes the inhibition is REAL. You need some major help and thankfully there are some great products out there to get your Silicone Paint to stick! I advise every long-term Silicone Artist out there to have one or all of these products on hand at all times:

You can use a product called InhibitX (I love the stuff, others don’t, just preference).

There is a full page of instructions for this amazing product that I will let you research for yourself but basically, it’s a liquid you brush or spray on that acts as an adhesive and bond for your paint to your piece. Some say it causes browning. I have never had that happen so ‘User Be Responsible’.

Some will use just NOVOC GLOSS for their cleaning and re-prepping. I learned from Christina Whiting that NOVOC can help open the actual “pores” of the silicone allowing your silicone piece to take paint more easily. A particulate mask (respirator) is always advised when using chemicals but I don’t because it doesn’t have any “volatile organic compounds” and that’s where the name NOVOCS came from but please, use one if you feel it’s necessary.   Here is what that looks like:

I also REALLY LOVE FuseFX’s BONDFX. Expensive BUT is a two-part Platinum silicone coating that can be brushed or sprayed over tin based silicones, rendering the surface compatible with platinum silicones. And that also means surfaces that have been contaminated with inhibitors.

Well, that’s it for now! A bit of a long post, eh!!! Let me say now, that this is all from my, ( KrisC from The Dainty Loft), experience. Some may have other ideas or suggestions and that is GREAT! Whatever works! These are the things that work for me! AND I will gladly and gratefully add to this whatever information other Professional Pourers/Painters/Silicone Makers (rhymes, lol) have to offer!!! So please write me if you do!!!

Once I couldn’t figure out why my kit, fresh out of the box and washed and prepped, wouldn’t allow my paint to stick. I TRIED EVERYTHING. In the end, the Pourer helped me and I covered that baby head to toe with Inhibit X and it was a DREAM to paint!!! Once, on another kit, I had to do the same with BondFX because the InhibitX wouldn’t work. I guess what I am saying is if you’re going to work with Silicone, there are guarantees to have paint issues and you’re going to have to be a Detective and go through a rigorous (and yes! stressful, especially if its a custom) time to figure things out and fix it.

* I do want to say, that in the past we may have thought if our paint wasn’t sticking the problem could lie with the Pourer or the place where we got the kit. That they made a bad kit or a kit that just inhibits paint. With much research from many Smooth-On Reps that information for me has changed. Unless the Pourer made its kit or mold out of tin or another non-platinum based silicone, the problems that occur with inhibition have predominately been issues that are the ones listed above and not with the Pourer. What CAN happen is it still has the Release agent on the kit and it’s being stubborn to come off.)ALSO, on the topic of Pourers, it’s so important to buy from a reputable Pourer or Company. Chinese KnockOffs and Silicone dolls have WRECKED the industry and I 100% do not recommend painting their silicone or vinyl dolls.

I hope this post and information helps you and thank you for taking the time to read it.

*some information has been referenced from Tom McLaughlin’s book Silicone Art… an excellent source for any Silicone Artist’s toolbox 🙂