Brushing glazes

[Bill T.]

I glaze by brush or spraying. Have been mixing glazes for about 2 years with the typical results, some great, some OK, some Ugh, from various Cone 6 recipes. Many of the glazes just don't brush smoothly. I have searched often for the additive that will make them brushable, but still confused or just plain can't figure it out. Example: Ron Roy's Black, a nice black, but does not brush well, spray OK if thinned and several coats applied. What should I add to my glazes to make them brushable? I use Laguna B-Mix and Speckled Buff bisqued slowly to Cone 04 fired to Cone 5-6.

[Mark C.]

I'll let others chine in about additives for brushing s cone 5-6 is not my range.

I will say for even applications dipping/pouring is best for me -its the quickest as well-I have learned it well

second best is spray-thats the most even coating on a spinning wheel-but slow- I feel this is the most even everywhere-a bit harder to master

Brushing is the thinest unless many coats are used and the most uneven of the three-as well as the slowest.

I do lots of under glaze brush work but pour the inners and dip or pour the outers

Mark

[bciskepottery]

You can add glycerin (available from a drug store/pharmacy) to make glazes more brushable; glycerin will add to the drying time, however. Other options are adding some gum arabic (available from arts/crafts store), or other commercial additives. Most of the glaze recipes you find in books, on-line, are formulated for dipping, not brushing. Ron Roy's Licorice is one of my favorites, but I dip, not brush.

[Bill T.]

You can add glycerin (available from a drug store/pharmacy) to make glazes more brushable; glycerin will add to the drying time, however. Other options are adding some gum arabic (available from arts/crafts store), or other commercial additives. Most of the glaze recipes you find in books, on-line, are formulated for dipping, not brushing. Ron Roy's Licorice is one of my favorites, but I dip, not brush.

 

 

Thanks for the info. I bought some gum arabic today and tried it. Seemed to work much better, but expensive. I'm going to try a commercial additive when I place my next materials order.

[neilestrick]

I used to work as the tech for one of the pottery supply companies here in the midwest. Our line of brushing glazes used a combination of Vee Gum-T and CMC gum. They brushed beautifully. The problem with cellulose gum products or other organic gums is that they get eaten up by bacteria very quickly and lose their effectiveness. It can happen within a few days. You could add more gum as this happens, but it's not that easy because the gum must first be made into a syrup before adding it to the glaze, so eventually you'll just have way too much water in the mix. The commercial glazes all have some sort of biocide in them to keep the bacteria at bay. That's why commercial glazes smell the way they do. In the old days it was formaldehyde. Now they have other products, but they serve the same purpose. We used to get 5 gallon buckets of the stuff, which lasted us a year or two in production. I don't think you can even buy small enough batches to make it worthwhile from a cost perspective. Some people say that a small amount of copper carbonate/oxide added to the glaze will preserve it, but personally I have not found it to be as effective. Basically, it's difficult to make your own glazes that will brush as well as commercial glazes, at least in a long-term time frame.

[Bill T.]

I used to work as the tech for one of the pottery supply companies here in the midwest. Our line of brushing glazes used a combination of Vee Gum-T and CMC gum. They brushed beautifully. The problem with cellulose gum products or other organic gums is that they get eaten up by bacteria very quickly and lose their effectiveness. It can happen within a few days. You could add more gum as this happens, but it's not that easy because the gum must first be made into a syrup before adding it to the glaze, so eventually you'll just have way too much water in the mix. The commercial glazes all have some sort of biocide in them to keep the bacteria at bay. That's why commercial glazes smell the way they do. In the old days it was formaldehyde. Now they have other products, but they serve the same purpose. We used to get 5 gallon buckets of the stuff, which lasted us a year or two in production. I don't think you can even buy small enough batches to make it worthwhile from a cost perspective. Some people say that a small amount of copper carbonate/oxide added to the glaze will preserve it, but personally I have not found it to be as effective. Basically, it's difficult to make your own glazes that will brush as well as commercial glazes, at least in a long-term time frame.

 

 

Thank you Neil. Your comments have given me some ideas. Going to give this a try since I usually only mixed small amounts up to about 500 g.

[Idaho Potter]

I've been playing around with some VERSA cone 5 majolica glazes and loved their red. Am working on a project whereby I knew the ready-made pint of red wouldn't be enough so I ordered 5 lbs. dry and was a little upset that it turned out thin and runny and settled out quickly. Their dry mixes don't come with brushing medium included. Duh! What is majolica but brushing application? Anyway, ordered brushing medium to add to the mixed glaze. Okay, had to mix it up to the point it would flow, but not too thick or thin. Sieved it, added it slowly to the mixed glaze, sieved it again--adding enough extra water to make it the same consistancy of the liquid pint of glaze.

 

Was it worth the trouble? Don't know, the project is on hold for awhile. As to the brushing medium, I don't know what it consists of but it wasn't very expensive (unlike the glaze!), and three coats brush on evenly.

[SShirley]

There is a product called "Magma", by David Pier which helps make glazes less settling and more brushable. But be careful not to add too much or the glaze turns into spackle.