How To Use Underglaze
Let’s talk about underglazes!
What is Underglaze?
Underglaze is basically paint for your ceramics. It stays where it’s applied and does not run or mix when fired like regular glaze. Underglazes come in a huge variety of colors and can be mixed together to create custom colors. They can even be layered like watercolors. You can apply it to greenware or bisque fired clay.
What kind to use?
I use Amaco Velvet Underglazes. They are consistent in color, and when paired with Amaco Zinc Free Clear glaze, they do not run. They give you the ability to add unique details that stay in place on your pottery (unlike glaze that will run and mix when it’s fired). This post is not sponsored by Amaco (I wish it was, ha!). I get so many questions about what type of underglaze and glaze I use so I’m sharing it with you-this is the combo I use and it’s always consistent. I often purchase these products from Blick Art Materials because they have reasonable shipping (even free sometimes) and have sales, but you can most likely find Amaco Underglazes and Zinc Free Clear at your local clay supplier. You can occassionally find them on Amazon as well but I haven’t had much luck, and they seem to be more expensive there than through Blick.
When to apply?
Let’s use the example of a ceramic spoon. I always apply the underglaze to bone dry greenware. This means the spoon has been made, and has completely dried out before I apply underglaze. It is ready for a bisque fire.
Note: many artists apply underglaze after the bisque fire, that works too but my technique is to apply before bisque firing.
Once spoon is completely dry, I will carefully apply any dots, lines, and designs before putting it into the first fire. I choose to do it this way because:
the bisque fire permanently sets the underglaze to the piece. It will not run if you brush glaze over the top of it.
it gives me the opportunity to change/edit/adjust any imperfections that I may notice before the final glaze fire. Sometimes I need an extra dot, or an edge is a little wobbly. I can still add a small amount of UG to my piece before glaze fire.
How to apply:
I primarily use Jet Black underglaze for my work. I apply with a Fineline Applicator for small dots, or the handle (not the bristles) of a brush for larger dots. See demo of applying dots with brush handle below.
If you want to cover a large area with underglaze, brush on 3 coats changing direction with each coat to ensure even coverage. (Example: brush one thin coat horizontal, second coat vertical, and third coat horizontal).
What if you “mess up”?
If you have a small area that needs to be cleaned up, use a needle tool, or trimming tool to carefully scrape away the underglaze. ALWAYS wear a mask, and if possible do this outdoors because it creates dust and clay dust is dangerous. Be very gentle when scraping away the underglaze because your piece can be easily and permanently scratched.
Quick Overview:
Apply underglaze to bone-dry greenware using an applicator, or brush
Bisque fire
Apply Amaco Zinc Free Clear by dipping or brushing
Glaze fire
Potential Issues:
If the underglaze is applied too thick it will crack.
Occasionally the UG will create a small, sharp bump on your work after the bisque fire. Carefully sand it with fine sand paper (like 320 grit) and apply a little more underglaze if needed. Glaze, and fire.
Supplies:
-Dot applicator (through Blick) or Here (Amazon)
-Brush
I hope you found this post helpful! I would love to see what you create, feel free to tag send me a pic or tag me on Instagram @helloceramicsstudio
This post contains affiliate links, I may receive a small commission of sales from the links on this page at no extra cost to you.
