Countering the effects of gum in commercial glazes

[moh]

Anyone know how to counter the effects of gum in commercial glazes?

Since the whole point of gum is to slow the drying and make the glaze paintable I'm trying to do the opposite and spray the glaze + have it dry like normal glaze.

 

[Hulk]

Good question!

Brushing/brushable glaze might spray ok.

Sprayed coating, we want the material to "wet" the surface, lay down flat, stay put (not run/drip) ...and somewhat else I'm not remembering just now.
If you give it a try, let us know how it goes?

[neilestrick]

Gum is added specifically to make them brush nicely and to harden the surface so that added layers don't pick up the previous layer. Part of what makes that work is that you have a higher water content in the glaze, plus the gum itself makes the glaze slimy and slows down drying. That is definitely a problem when it comes to spraying, so I would first see if any of the glazes you like to use are available in dry form so that you can mix them without any gum. If not, then I think you're just going to have to spray them in thinner layers, letting each layer dry between applications. Or you can start mixing your own glazes.

[Min]

15 hours ago, moh said:

Anyone know how to counter the effects of gum in commercial glazes?

 

Try freezing a test amount of it. If it works you will probably need to increase the specific gravity of the glaze for spraying it without overwetting the pot.

[Russ]

I use cmc gum in all my glaze formulas and I dip and spray. When spraying I add water so it goes thru the sprayer easier.  I didnt know there was a problem with gum and spraying and dipping for that matter.  My philosophy is this... its all just one big experiment and thats how we learn.

[Min]

17 minutes ago, Russ said:

I use cmc gum in all my glaze formulas and I dip and spray

What percentage?

[Bill Kielb]

20 hours ago, moh said:

I'm trying to do the opposite and spray the glaze + have it dry like normal glaze.

Likely need thin the glaze to spray. Dry the glaze as needed with half pull of the spray gun trigger - air only - should make spraying more doable. It’s good practice to learn the thickness with some test tape when spraying with glaze, since it’s thin to work in the sprayer it will go on very even, but thinner than dipping. Usually requires several even coats dryed in between by “air only“ from the sprayer. Don’t forget proper  mask and ventilation!

[Russ]

Well thats a good question.. probably 1 to 3%.  I mix the cmc in a gallon jug with water and let it set a few days. Then add a quart or two to about 4 gallons of glaze when mixing.  In this amount it gives even the most powdery glaze a nice hard coat when dry.

[Min]

1 hour ago, Russ said:

Well thats a good question.. probably 1 to 3%.  I mix the cmc in a gallon jug with water and let it set a few days. Then add a quart or two to about 4 gallons of glaze when mixing.  In this amount it gives even the most powdery glaze a nice hard coat when dry.

Agree with you that gum(s) are great for hardening powdery raw glazes and with some glazes that just don't want to layer up without lifting. I'ld hazard a guess there is much more gum in a commercial brushing glaze than what would be in a dipping glaze to prevent those issues though.

[Russ]

I also spray a commercial underglaze (Coyote Clay) Thinning it down  helps with spraying but I try to do at least 3 coats. Being thinned it is absorbed into the bisque quickly allowing the next coat almost immediately.  Im just saying Ive never had any problem with gum in a glaze granted I dont and have never used a commercial glaze as I mix my own.

[PeterH]

A couple of previous threads.

... possibly defloculate

... mix well and possibly screen

 

... wash out sprayer as soon as you've finished

[Min]

2 hours ago, PeterH said:

... possibly defloculate

Yeah, I'm thinking in this case that might not work as well for the OP here as they are looking to speed up the drying time and defloc's slow it down.