I’ve been using Kato Liquid Clay in the studio for a very long time and have to say it’s one of my favourite products.  I use it as a sealer, as a glue, I use it to create decorative surface techniques, I mix things into it…the list goes on.  It took me a long time in the beginning to get the perfect finish using this product and I burnt many beads.  I learned from my mistakes and after lots (and I mean lots) of practice I can now create a luscious, glossy surface on all my polymer clay components with ease.

These are two of my very early pieces.  In fact the bead on the right was one of the first beads I made using kato liquid clay and an inclusion – the kato liquid clay was cured with a heat gun in both instances.  These beads are around 11 years old. The surface is still glossy, smooth and hard.

I was surprised to read a conversation online about an issue with kato liquid clay surface going sticky/tacky/oily over time.  Surprised because it was the first I had ever heard of this happening and I had never seen it on any of my pieces (and I have lots of them).  Luckily a friend of mine, Dani from The Whimsical Bead, sent me some of my own pieces which had been purchased a couple of years prior so I could see for myself.

These photos were taken as the pieces came out of the envelope.  You can see the square, blue component and the last orange/brown component are stuck to the plastic.  The others floated freely in the plastic bags.  I took them all out of the bags to check the surface and the two affected were slightly oily but not to the extreme.  My fingers didn’t stick to the surface like they would to sticky tape.  It was like I had popped some oil on a cloth and wiped over the surface with it. I simply buffed them on a soft cloth and it cleaned up nicely.  These pieces are all staying in the bags on the shelf so I can monitor them and check if this “oiliness” returns.

I decided to go searching through my gigantic stash of work to find more pieces that may be affected.  I ended up finding some small sample squares which had been painted with glass paint and then a coating of kato liquid clay (again the liquid clay was cured with a heat gun).  These squares had been stored in a plastic, clear sheet protector and have been there for about 4 years.

You can definitely see a slight “oiliness” to the surface of the piece on the left.  The piece on the right has been buffed.  This is also on the shelf to keep an eye on.

So now I knew what this sticky/tacky/oily issue looked and felt like, I wanted to know why.

I contacted Van Aken International who manufacture the product. I contacted Donna Kato who obviously has used the product extensively.  I spoke to numerous instructors who use the product in both live classes and written tutorials. I asked online for those who had experienced issues regarding the oiliness to contact me and I spoke to many people in the general polymer clay community about this issue.

This is some news from Van Aken:

  • The formula for the product has not changed over the last 4 years.
  • Under cured liquid clay could very well be the cause, if under cured the polymers have not completely hardened and fused together.
  • It’s important to stir your liquid clay thoroughly before use.
  • No comment could be made regarding storage or climate as these factors had not been tested.

Donna Kato had never had anyone raise this issue with her and had not noticed it herself.  She did however indicate it could be either under curing or a reaction to a certain surface treatment.

I know from speaking to many members in our polymer community, under curing is an issue.  Perhaps fear of burning and ruining your piece could be a reason why many people under cure their liquid clay.  This could have an effect on the long term outcome of your work. I also know there are those who simply use too much liquid clay which then in turn takes forever to cure so the risk of removing the heat gun prior to fully curing is highly likely.

After many conversations with different people I concluded there could be a number of possible reason for liquid clay coated pieces to react over time.  These being:

  • Under cured polymer clay.
  • Climate/humidity.
  • Storage in plastic.
  • Reaction to a specific surface treatment.
  • Not stirring your liquid clay frequently enough.

Let me just say there are a few important rules to ensure you get the best possible outcome every time.  Let’s run through some information I feel is important.  I should point out, I always cure my Kato liquid clay with a heat gun.  I know there are some who only cure in the oven and I know there are some who cure with a heat gun and then pop in the oven to cure again.  It’s all about working out what is the best way of curing kato liquid clay for the work you’re creating.

  • Don’t store finished pieces in plastic (this could be a reason for the oiliness reaction so it’s best to simply avoid it).
  • Be careful what surface treatment you use and perhaps do some testing first.
  • Make sure each coating of Kato liquid clay is cured properly.
  • Stir your bottle well.
  • Clean your pieces with a soft cloth to shine.
  • Try popping your work back in the oven for a final cure after your Kato liquid clay coating has been cured.

Let’s have a look at some of the products I’ve coated with success.

  • Chalk pastels.
  • Alcohol ink.
  • Foils.
  • Pan pastels.
  • Iron oxides.
  • Lake dyes.
  • Acrylic paint.
  • StazOn ink.
  • Acrylic paint pens.
  • Angelina fibres.
  • Mylar and films.
  • Crackle mediums.
  • Image transfers.
  • Foil melts.
  • Micro beads.
  • Friendly plastic.
  • Embossing powder.
  • Glass paint.
  • Liquid watercolour.
  • Swellegant.
  • Glitter.
  • Mica powder.

These pieces were all created at different times over the years and I still have them in the studio as they’re all sample pieces.  These photos were all taken one week ago.  The images contain beads with mica powder, StazOn ink, friendly plastic, glass paint, acrylic paint, image transfer, foils, iron oxide and embossing powder.

What should my liquid clay look and feel like after it’s cured?

  • The surface of your piece should feel smooth to the touch.
  • The feel of this product is unlike resin or sanded and polished polymer clay.  It should feel firm but not “rock hard”.
  • Multiple coats (more than 3) will have a softer, more rubbery feel.
  • The surface of your piece should be able to be wiped freely.
  • Kato liquid clay should be crystal clear if cured properly.  If you notice cloudy or milky patches on your surface, then you need to cure for longer.
  • If you try and stick your fingernail into the cured surface you will leave a mark (more noticeable on thicker coated pieces).  Remember this product is not resin so you need to protect the surface.

I wrote and released a tutorial a couple of years ago called “Curing Kato Liquid Clay And So Much More”.  In this tutorial I share my knowledge of kato liquid clay and run through, step by step, the coating and curing process.  There are lots of additional tips and tricks throughout the video to help you further, including looking at different heat guns, coating a variety of 3dimensional surfaces and more.  If you feel you need additional help with using and understanding Kato Liquid Clay you can find a link to the tutorial here:

Curing Kato Liquid Clay And So Much More

I don’t profess to be the ultimate expert on Kato liquid clay.  Others may have different experiences and that’s absolutely fine.  I’m simply sharing my opinion.  I absolutely love Kato liquid clay as a professional finish on my pieces and will continue to use this product.

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Neena Shilvock
4 years ago

I think perhaps it was a conversation with me you are referring to? Anyway, I know I had that conversation with you and have experimented since and you’re absolutely right, it’s undercuring that is the problem. Once I got over the fear of the heat gun – and it’s a scary fierce thing- and started to use it, my beads are fine and there’s no residue.
BTW, I wiped the residue away from my slightly under cured pieces with rubbing alcohol and they are fine now and it hasn’t come back.
Thank you for all your research etc. Neena

4 years ago

thank you so much for research on kato liquid clay , i really enjoyed read it. i have a question about how you did your veneer , how do you get the image tranfer get so clear and bright ? secondly how do you get your colors so bright ? do you have a pdf on how to do your beads?

Jan Pini
5 years ago

Can you explain what “glass paint” is?

5 years ago

Thank you, Debbie. I bought your tutorial and it’s really thorough. I haven’t tried it yet because: (1) I don’t yet have the proper heat gun, and (2) I’m still a bit timid about trying it. I usually either sand and buff or put on a layer of resin. I’d much rather have a piece that uses only polymer clay and surface effects. I can’t wait for payday and getting a proper heat gun. Thanks, again.

Wendy Moore
5 years ago

Thank you so much Debbie for your generous and enthusiastic sharing! Fantastic stuff. Hugs from here.