Cornstarch is widely used in polymer clay crafting to smooth surface imperfections, prevent burning during baking, and to help support pieces while they are curing. Because of its widespread use, people new to the craft are often left wondering how to remove cornstarch from polymer clay.
As long as the cornstarch was not pressed into the surface of the clay, then it’s pretty easy to remove. Most of it will easily brush away after baking if you rub the piece on some denim. If there are patches of cornstarch left on the surface after this, then you will need to soak the piece in some warm water and scrub it with an old toothbrush. Pieces that have stubborn patches of cornstarch may require sanding or a solvent to fully remove the residue.
What is cornstarch used for with polymer clay?
Cornstarch is widely used for preventing polymer clay from sticking to things. You can put a thin layer of it on your work surface, dip your tools in it to work more precisely, or rub a bit on your fingers to smooth out any imperfections. It is often promoted for removing fingerprints or dents.
It also can help protect the clay during baking both from moving around the pan and browning. You can roll your whole piece in cornstarch to create a barrier between it and the direct heat from your oven. This way it will get hot enough to cure properly but won’t burn in the meantime.
Remember to cure your pieces for a longer period of time when they’re coated like that. The heat will need more time to reach the clay, particularly at lower temperatures.
If you bake your pieces in a bed of cornstarch, you can be sure that their original form will be kept intact, and that there won’t be any sagging or parts stuck together.
A cornstarch bed is really useful for curing beads. It will stop them from rolling and damaging each other in the process.
You can also coat your molds or other textured tools you’ll be using with it to protect clay bits from leaking out and damaging them.
Will cornstarch change the surface of the polymer clay?
If you overdo your smoothing with cornstarch, it can cause a white coating. Do not scrub hard on your piece. That will cause the cornstarch to get inside your piece’s surface and you won’t be able to get it out easily – at the very least you will have to sand the surface.
Despite the fact that cornstarch can be a useful tool, it’s important to avoid using it in excessive quantities. Use as little as possible. You can always add more if your piece needs it.
Do not use cornstarch on pieces that have liquid polymer clay in them. It will bake into the surface and you won’t be able to remove the white particles later.
Do you have to sand cornstarch off of polymer clay?
As long as you don’t press the cornstarch into the clay, or use too much, then most of it should rub or brush off after baking. However, it does sometimes have to be sanded off the piece using successive grits of sandpaper to create a smooth finish.
Will cornstarch change the color of polymer clay?
Cornstarch is used to protect the colors of your polymer clay when baking, not to damage them. But sometimes some of its particles can get stuck into your clay when curing.
Very soft brands of clay that tend to get sticky while being worked are more likely to get patches of cornstarch stuck. This can change the color of your piece’s top layer causing light spots and discoloration. Most of the time this is preventable or reversible.
Do you remove cornstarch from polymer clay before or after baking?
It is usually easy to remove cornstarch residue after baking. All you need is running cold water, a little bit of soap, and a soft toothbrush to gently scrub off the white particles.
You can leave your piece to rest in the water for 10-20 minutes. This will get rid of most of the particles and leave you to scrub off only the most stubborn ones.
If for some reason the cornstarch is still there after rinsing, try rubbing your piece with a mild abrasive or coating it with liquid clay and rebaking it. The layer of liquid clay will leave its surface shiny and hide any imperfections.
If the residue is visible in a small area, use a cotton swab dipped in a stronger solvent like alcohol or acetone to remove it. Or just paint over it with acrylic paint.
Will cornstarch make polymer clay weaker?
If you leave your unbaked polymer clay piece in cornstarch for more than a couple of minutes, then the plasticizers will be absorbed into the cornstarch which will lead to a much weaker surface. This will make the cured piece way more brittle and will possibly cause cracks.
It’s best to use the cornstarch right before putting your pieces in the pre-heated oven.
Some brands of clay react worse than cornstarch than others, and some don’t seem to react at all.
Are there are alternatives to using cornstarch with polymer clay?
Baking soda (sodium bicarbonate) is sometimes used as an alternative to cornstarch.
However, baking soda has a rougher texture and won’t help you smooth the surface of the polymer clay. In fact, it can leave dents and surface imperfections if it isn’t used carefully. Some people report that it also leaves stains on clay that are hard to remove.
Some crafters use baby powder or other starches, like arrowroot, potato, or tapioca powder as a substitute for cornstarch. It’s important to keep in mind that most flours and powders found in the kitchen will become very difficult to remove once they get wet and heated – so make sure you always experiment with a test piece of clay first.