A clear glaze that I have used for years crackled badly so much so that it can be lifted off the pots. Ther was a slip underneath that was fired in during bisque. On top of the slip was underglaze. Anyone any idea? The glaze also underfired. 

Views: 206

Attachments:

Reply to This

Replies to This Discussion

it might be a silly question on my part but was the underglaze fired before putting on the glaze? Also did the glaze peel from all over the pot or just over the slip or underglaze?

No, it was not fired in. If fired in the color is much stronger and when glazed without firing in it is more pastel, which is what I was looking for. I have done either before without ever having problems. The glaze peeled from all over. I am suspecting that clear glaze bucket - the green and blue liner glazes used on some did not crack. This is the downside of using glazes in a collective - you never know what someone else did to it before. [Note to self: always use your own glazes]

One of the problems with bucket glazes is convincing people to be certain that they're completely mixed.

When a bucket of glaze has an inch of solids at the bottom, you're missing most of some of the glaze ingredients.

So what you're applying is not actually a glaze.

People tell me they like bucket glazes but few are willing to actually put their hand in to feel if any has settled out.

I have a glaze that is usually very well behaved but the last time I made a batch it started cracking and flaking off the pot.  I can still use it but now need to apply and fire, reapply - particularly in the bare patches and refire. After the second fire it's great but I'm going to make a new batch and calcine some of the clay in the glaze to hopefully give less shrinkage.  This glaze is a wonderful bronze that's pretty important in my work so I don't want to abandon it.  Something that can help too is 1-2% CMC Gum in the glaze.  If it was a glaze you make yourself I think Insight can help with re-formulating the glaze; this is the route I think I'm going to go with my bronze if calcining doesn't work.  

Any chance that you erred when mixing the glaze?  Put in a wrong ingredient or twice of an ingredient or such?  It's pretty easy to do, and might not be noticed.  I'd be tempted to mix up a small batch, being very careful, and testing it to see if it behaved.  

Reply to Discussion

RSS

Videos

  • Add Videos
  • View All

Use These Links to Support Us

Low cost flat lapping disc can be used on you potters wheel if you, drill bat pin holes in it, and provide a trickle of water to cool it. At amazon.com, 120 grit for aggressive material removal. Click the image to purchase 

Members have had great things to say about John Britt's new book, Mid-Range Glazes. Click the image to buy from Amazon.com

Purchase Glazes Cone 6 by Michael Bailey, The Potters Book of Glaze Recipes by Emmanuel Cooper, or Making Marks by Robin Hopper, all available at amazon.comMastering Cone 6 Glazes by John Hesselberth & Ron Roy is now out of print.

Harbor Freight is a great place to find unbeatable prices for better HVLP spray guns with stainless steel parts and serviceable economy models, as well as detail guns, all tested by our members for spraying glazes, as well as compressors to power the guns. As yet no one has tested and commented on the remarkably inexpensive air brushes at harbor freight.

The critter siphon gun is a spray alternative that is well liked by some of our members, and is available at amazon.

Amazon is also a competitive source for photo light tents for shooting professional quality pictures of your work. They also have the EZ Cube brand favored by several of our members. You might also want to purchase the book Photographing Arts, Crafts and Collectibles . . .

If you are up to creating videos of your work or techniques you might want to invest in a flip video camera

Following are a few scales useful for potters. Ohaus Triple Pro Mechanical Triple Beam Balance, 2610g x 0.1g, with Tare $169.00

And finally a low cost clone of the OHaus. The Adam Equipment TBB2610T Triple Beam Mechanical Balance With Tare Beam $99.62

ebay is a great alternative for many tools and the equipment used in the ceramics studio - kilns, wheels, extruders, slab rollers are often listed there both new and used.

Tips for Members

If you just want to spout off, it is best accomplished as a blog posting. If you want to get more guidance and ideas from other members, ask a question as a new discussion topic. In the upper right corner of the lists for both types of posting, you will find an "+Add " button. Clicking it will open an editor where you create your posting. 4/16/2014

© 2024   Created by Andrea Wolf.   Powered by

Badges  |  Report an Issue  |  Terms of Service