Comparing Liquid Polymer Clay Brands as a Coating

Which brand of liquid polymer clay is the clearest? Which can be used as a sealer or as a resin substitute?Wait. Is that right? How can there be LIQUID polymer clay? Isn’t that an oxymoron like “jumbo shrimp? Well, I think that causes a lot of confusion about what, exactly, liquid polymer clay is and how it can be used. Liquid clay is just what the name says, it’s a liquid version of polymer clay. There are three major brands of liquid polymer clay (Sculpey, Kato, and Fimo). Soon Sculpey will have a new member of the liquid clay family, Sculpey Clear (Transparent). I sat down with these common brands and put them through their paces. Here’s what I found when I compared these four liquid polymer clay varieties.

Summary

  • Liquid polymer clay is just polymer clay without binders and fillers
  • In April 2017, there will be a new Sculpey Clear that looks very promising
  • Translucent Liquid Sculpey (TLS) makes an excellent matte surface coating
  • All liquid clays will clear further with a heat gun, but Kato Liquid will clear completely
  • Kato Liquid makes an excellent glass-like glossy clear coating when used with a heat gun
  • Thin coatings of liquid polymer clay will cure frosty-to-clear, but thick coatings can plaque and be quite opaque
  • Sculpey Clear is the clearest of those tested when used thick, as in a mold or bezel

What is Liquid Polymer Clay?

Polymer clay itself (the putty/dough/clay) that we know and love, is made from polyvinyl chloride (PVC) particles suspended in a plasticizer. To turn it into a dough, binders and fillers are added. Liquid polymer clay has the same basic ingredients as the dough, but it lacks the binders and fillers. So it’s runny like a liquid and comes in a squeeze bottle. But just like our beloved polymer clay putty, curing with heat causes the particles of PVC to fuse, locking with the plasticizer to form a solid, yet flexible, mass.

Here are the brands of liquid polymer clay that I tested for this article.
In this article, I compare Translucent Liquid Sculpey (TLS), Liquid Kato, Liquid Fimo, and Sculpey Clear. The new Sculpey Clear will be in stores in April 2017 and the advance sample I received did not yet have a label!

All brands of liquid clay can be used in many of the same ways. It’s excellent when used as a bakeable glue to enhance the bond between clay pieces, to soften crumbly clay, with pigments to make a faux ceramic, as a drizzle for polymer clay food miniatures, and as a fixative for surface effects. You can use any brand of liquid with any brand of polymer clay. But today I’m focusing on how you can use liquid polymer clay as a coating or clearcoat when you don’t want to use a varnish or other “sealer”. (Not sure what I mean? Have a look at my article on polymer clay clearcoats here.)

Thin coats vs thick layers of Liquid Clays

While the baking temperature on the bottle’s label is as low as 265°F (130°C), I found that you will get a much clearer result when you bake at 300°F (150°C), regardless of brand. In addition to that, you can use a heat gun to further clarify thin coats. See examples below.

Four brands of liquid polymer clay baked at 265°F. Four brands of liquid polymer clay baked at 300°F. Four brands of liquid polymer clay baked at 265°F. and then further clarified with a heat gun.

It’s a bit misleading in the above photos, but all the brands DID get more clear after a heat gun was used on them, even the Fimo Liquid. But as you can see, it was Liquid Kato that had the greatest increase in clarity. When placed over print, you can clearly see through both the Liquid Kato and the Sculpey Clear. (I know the picture isn’t that clear. It’s hard to photograph clear things!)

The above samples were drops poured into a fairly thin puddle on a piece of glass. What would happen if liquid polymer clay were baked in a container, such as a glass vial or perhaps in a mold? Would it be clear like resin?

Liquid polymer clay is not very clear before baking.
Liquid polymer clay in glass vials, before baking.
Liquid polymer clay can be quite clear when used thin, but it will never be as clear as resin after baking.
Liquid polymer clay in glass vials after baking a 300°F (150°C) for 45 minutes.

Liquid polymer clay can be quite clear when used thin, but it will never be as clear as resin after baking.

As you can see, liquid polymer clay, when poured thick, can be quite opaque and can even discolor. Note the profusion of bubbles in the Liquid Fimo. The liquid Kato discolored the most, even though its label directions do say to bake at the temperature I used.

So…thin coatings work best when you’re trying to get a clear result. What happens if you use liquid clay in a bezel, as a substitute for resin? Well, you know I had to check that out, too.

Here's how different liquid clays compare when used as a coating in a bezel.
Here you’ll see what happens when liquid polymer clay is used to fill a bezel, then baked. Note how clear Sculpey Clear is in this situation and how TLS is not very clear. **Note** For these samples, liquid clay was poured over raw cane slices, then baked together. The Liquid Kato did not make all those bubbles when it was used as a coating over baked clay. In fact, it worked beautifully. Also note the slight color change the coatings added.

Interesting, isn’t it? Well, let’s read on to learn more about the individual brands of liquid polymer clay. As you might suspect, each brand has slightly different working characteristics and therefore has different optimal uses when it comes to making a clear coating.

Heat Guns

To clarify liquid polymer clay, it’s helpful to use a heat gun. What kind? You can get okay results with an embossing heat gun from a craft store. But I find that it doesn’t get hot enough. I use a heat gun from the hardware store, the kind that’s used on heat-shrink tubing and to strip paint. It’s helpful to have both variable speed fan and variable heat settings for maximum versatility. Unfortunately, though, a hair dryer will not be hot enough.

Translucent Liquid Sculpey

Translucent Liquid Sculpey is the first liquid clay that I remember being on the market and it’s often referred to by its initials, TLS. The label has changed over the years, but the formula appears to be the same. TLS appears white, has the consistency of white glue, and is fairly grainy when you rub it between your fingers. It has a mild smell similar to that of Premo.

Translucent Liquid Sculpey has changed labels (and names) over the years, but it's still the same stuff.

After baking, TLS has a slightly milky appearance and is not completely translucent. It can often have lots of tiny bubbles, but that seems to diminish in thin coats or when warmed very slowly. Because of this, it’s best used in applications where clarity does not matter. It can be used as a coating, but results are best when used quite thinly. TLS is matte after baking so it makes a wonderful matte protective coating for surface treatments. Just sponge on with a cosmetic sponge and bake. While TLS is matte when oven baked, but it will take on a slight shine, sort of like a satin, when a heat gun is used on it.

TLS, when used as a coating, gives a matte finish that's not perfectly clear.
Note the slightly grainy and perfectly matte finish that comes from using TLS as a coating. There is some cloudiness, but it is perfectly clear when sponged on and then baked.

Translucent Liquid Sculpey also makes a really good bakeable glue and is good for moistening crumbly clay. It is an excellent all-purpose liquid clay, but isn’t a shiny clearcoat. It’s an excellent matte surface effect. TLS has a dry, hard feeling after baking that is similar to the surface of any polymer clay. Contrary what is seen in an often-shared YouTube video, I have never (never!!) been able to make thick coatings of TLS become clear by using a heat gun.

Fimo Liquid

Formerly known as Fimo Deco Gel (Deko Gel in European packaging), Fimo Liquid is a cloudy-appearing liquid with a distinct odor that I can’t describe but can easily recognize. It has obvious granules in it that appear to be suspended in a runny honey-like liquid. Fimo Liquid can bake quite clearly when poured into a bezel, but if it’s too thick, it will have lots of bubbles and plaques. After baking, the surface of Fimo Liquid has a slightly rubbery feeling to it. The surface also doesn’t bake shiny, rather it bakes up to be a semi-gloss or satin. Because of this, you will need to coat the surface with a glossy varnish after baking in order to get a glossy finish.

Like all other liquid clays, Fimo Liquid works nicely as a bakeable glue and to soften crumbly polymer clay. I like using Fimo Liquid as an all-purpose liquid clay, and it’s stellar as a colored glaze in faux ceramic effects, but it’s not my favorite for creating clearcoats.

Liquid Fimo can sometimes leave an alligator-skin surface.
I know that some people have had very good flawless results with Fimo Liquid, but for me it forms lots of bubbles, plaques, and the surface can have a fine, pebbly grain at times.

Kato Liquid Polyclay

Years ago, when Kato Polyclay first came out, Kato Liquid Polyclay was known as “Kato Sauce”. It’s a white, runny liquid that’s very similar in appearance to white glue. After baking, it becomes a milky clear color. There is no noticeable graininess to Kato Liquid. The odor is the same as the distinctive “vinyl baby doll” smell that blocks of Kato have, but perhaps not as strong. After baking, Kato Liquid has a rubbery, vinyl feeling and makes excellent window clings.

Kato Liquid is unique in that it can be made to be completely clear when you use a heat gun on it. You can do this after baking, or you can just use the heat gun to cure the Kato Liquid. If you do this with several thin-ish coats, you can get a remarkably clear surface treatment. Doing this will make the surface extremely glossy and glass-like. The surface will also be hard, eliminating the rubbery feeling and making the surface able to be sanded without balling up and peeling.

Of course Kato Liquid does all the normal liquid polymer clay things, too, so it’s really quite a good bottle to have on hand.

Kato Liquid Polyclay gives a glass-like shine after baking, especially when cured further with a heat gun.
Kato Liquid Polyclay gives a glass-like shine after baking, especially when cured further with a heat gun.

Sculpey Clear (Transparent)

Not yet on the market and being released as part of Sculpey’s new products for 2017, the newest of their liquid polymer clays is Sculpey Clear. (I’m not sure of the name, actually, as the advance sample I received did not yet have a label.) It is very much unlike the other three liquid polymer clays in this article, and I think we have a wonderful new addition to the lineup!

Sculpey Clear is also a runny white syrup, similar to white glue when unbaked. It doesn’t have any graininess. It does not seem to form bubbles during the curing process and bakes remarkably clear, yet with a slight cloudiness. Compared one-on-one, it does not get quite as clear as Kato Liquid, but it’s awfully close. After baking, it has a slightly rubbery feeling that doesn’t go away when a heat gun is used.

Sculpey Clear can sometimes have small pits in the surface, making a second coat necessary.Sculpey Clear is perfect for filling bezels (if they’re not too thick) and is a good, bakeable alternative to resin. The surface of Sculpey Clear is semi-gloss after baking. It is not glossy and would need a coat of Varathane to become glossy.

You can make Sculpey Clear more translucent after baking when you use a heat gun, but it does not clarify in the dramatic way that Kato Liquid Polyclay does.

 

One odd drawback to Sculpey Clear is an unfortunate tendency to cure with small pits in the surface. They’re not huge, but it can mean you need to give it another thin coating and bake once again.

Sculpey Clear gives a semi-gloss finish when used as a coating, but it's quite clear.
Sculpey Clear gives a semi-gloss finish when used as a coating, but it’s quite clear. (The cloudiness you’re seeing in this picture is actually glare from the shine.)

Using Liquid Clay to fill Bezels

A common use for liquid polymer clay is to fill bezels to create a coating over some decorative element, such as (in this case) a really neat cane slice. For thick, domed coatings or for covering complex textured items, you’ll have better luck with a resin. But for simply filling a thin bezel or levelling an uneven area, liquid clay works well. TLS isn’t very clear when doing this, so I’d choose one of the others. As you can see in the photo below, the clearest results come from Kato Liquid Polyclay, but the next best is Sculpey Clear. Both gave clear, bubble-free coatings.

These polymer clay cane slices in bezels were coated with various brands of liquid polymer clay.
Clockwise from upper left is TLS, Fimo Liquid, Sculpey Clear, and finally Kato Liquid Polyclay in the lower left. All were baked at 300°F (150°C) and then further clarified with a heat gun.

Note the slight cloudiness of all but the Kato Liquid. This effect can be reduced greatly by coating the surface with Varathane, as you can see in the photo below.

Coating with Varathane will reduce the cloudy appearance of a liquid clay used as a bezel filler.
(Top to Bottom) Here’s Fimo Liquid, Sculpey Clear, and TLS that have been half-coated with Varathane to show that adding a varnish to the top of the cured liquid clay surface will enhance the clear and transparent result.

Using Liquid Clay as a Clearcoat

As I mentioned several times in this article, you can use liquid polymer clay as a clearcoat or sealer, especially when cured with a heat gun. This is best on items that are not heavily textured. For specific instructions on how to do this with Kato Liquid (the other clays are similar), go visit Debbie Crothers to buy her video on this very subject. She shows you exactly the way it’s done. No more varnishes, sealers, glazes or other sticky coatings. Liquid polymer clay is the perfect way to coat clay to have a protective surface.

Here is an assortment of beads using the various liquid clays. The base bead is just black Premo, baked, and the liquid clay was brushed on and then cured with a heat gun. Notice the varying gloss levels with the different liquid clays.

These beads were coated with different liquid polymer clays and then cured with a heat gun.
From left to right we have Fimo Liquid, TLS, Kato Liquid Polyclay, and the last two beads are Sculpey Clear.

Smoothness of a Liquid Clay Finish

I would love to recommend a liquid clay finish for all circumstances, but I have to say that I can’t. In all cases, the surface has specks, bubbles, and small irregularities. No matter how well you let it settle, use a dust-free environment, remove specks, etc, there always seems to be little bubbles and flaws in the surface. This just seems to be the nature of the beast. That doesn’t mean you shouldn’t use this technique, because it’s just so darned useful! But do be aware that it’s not going to be as smooth as sanding and buffing. I just wanted to give you a heads up so that you don’t beat yourself up wondering where you went wrong if you get specks. Okay? Okay! Now go get some liquid clay and a heat gun and have fun!

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