Fusible Decals on Glass Testing

Fusible decals are a wonderful way to spice up recycled glass designs with a small cost and a little effort.  There are many different kinds of decals on the market, including:

  • Low fire glass decals
  • Low fire ceramic decals
  • High fire ceramic decals
  • water slide decals
  • gold decals

How do you know which to use??  Good question, read on and let’s try to make some sense of all the information that is out there.

Waterslide decals:  most decals on the market today are waterslide decals.  This is a type of decal that is made by coating paper with a very thin coating of rice starch (or synthetic substitute) and then an undercoat.  The undercoat seals the starch to the paper.  The decal design is printed onto the paper at that point using a special printer that prints with under glazes or ceramic glazes.  These glazes are essentially the ‘paint’ of the decal.  Then an overcoat is added to seal the glaze to the paper.  When you are ready to use the decal, you cut out the desired design and drop it into a dish of warm water.  The decal will initially roll up, then relax as it hydrates.  This is caused by the paper absorbing water and hydrating the starch layer, which become slippery and ‘slides’ off the paper. Add this decal to your glass project, smooth away any excess water and air bubbles, fire, and you are ready to go.

The ingredients of the glazes ‘paint’ in the decal are what determines the firing temperature and how well the colors will hold up to heat.

There is an added complication that many of the decals on the market are tagged as for ceramics.  Can these also be used on glass?  Well, I did a bunch of testing to find out.  Let’s have a look.  All of my tests are uncapped, on float glass (the same sheet of glass for all tests to eliminate glass variation).

I’m testing several types of decals:

Low fire glass decals from Slumpy’s

Low fire ceramic gold decals from Glaser

High fire ceramic decals from Glaser


Low Fire Glass Decals

Low fire glass decals

Low fire typically refers to a lower temperature for maturing the colors of the decal.  The manufacturer recommends adding decals last, after all of the other firings are finished.  I wanted to know at exactly what temperature my kiln would fire these decals at their peak color, and if it could be one of the regular firing schedules I use all of the time.  The temperatures I used:

1225 F – I use this firing temperature to fire polish wine bottle drinking glasses.  It also seems to keep the colors bright for the decal.

1325 F – This is a slumping temperature.  We are starting to see the colors fade out from the decal.

1435 F – This is a tack fuse for float glass temperature and a full fuse for art glass.  This looks pretty bad

1535 F – Full fuse for recycled glass.  Most of the color from the decals is completely gone.

Conclusion:  For Low Fire Glass Decals, I’ll be using the fire polish firing schedule.


Low Fire Ceramic Decals

Low Fire Ceramic Decals

These decals are for glazed ceramic works, and are typically added last and fired to a low temperature.  Again, I wanted to test how these worked at my firing schedules.

1225 F – Colors are bright with very strong contrast

1325 F – Colors are still bright, but we are losing a bit of contrast

1435F – Losing color and contrast

1535F – Washed out color and low contrast.  Compare the two butterflies, it is interesting to see the difference.  Although the colors have washed out, we are not seeing the extreme loss of color that the glass decals presented at the same temperature.

Conclusion:  These decals are slightly more heat tolerant than glass decals (and come in a MUCH wider variety)


Low Fire Gold Decals

Low Fire Gold Ceramic Decals

Low Fire Gold decals are made with 22Kt liquid gold (think the rim of plates) and fired at very low temperatures.  They are brown before firing and the solvent burns off and they turn gold.  I was pretty sure that these would not survive full fuse, but wanted to check.

1225F – Perfect firing, sharp colors and strong gold.

1335F – Still looking pretty sharp, I was surprised and pleased by this result.

1435F – We are losing the gold and the color at this temperature

1535F – The gold is dull and brownish, the colors are quite washed out.

Conclusion:  These decals can be fired at either a fire polish or slump for good results.  For best results, use a fire polish schedule.


High Fire Ceramic Decals


These decals were tagged as High Fire, but after testing, I’m not completely convinced.  This is one of the very important reasons to test, often labels can get mixed or incorrectly sorted.  This decal is intended for the center of a plate.  You can see what happens as we run through out test firings.

1225F – Colors are dark and there is quite a bit of contrast

1325F – Colors are still sharp, still good contrast

1425F – Colors are still sharp, in fact, the purple of the grapes has more purple than the previous test

1525F – Decal has started to become translucent as the glazes burn off.

Conclusion:  These decals do in fact survive higher temperatures than the others tested, and could be used up to tack fuse temperature.

Additional Information:

Often ceramic decals have firing temperatures listed as ‘Cone’ temperatures.  This is my favorite Cone to Temperature conversion chart, although such charts are easy to find with a search if you don’t like this one.

Related Articles:

Firing decals on Bottles

Wine Bottle Lantern Tutorial

Slumping Bottles Vertically