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I am having some devitrification problems when i fire Bullseye cobalt blue glass. I purchased Spray A, and applied it will a brush, but it left some white streaks after firing. I'm trying to find the best way to apply the Spray A. I'm thinking that perhaps i should spray it on, rather than brush it on...perhaps that is why it's called Spray A. Just wanted to see if anyone can confirm that best way to apply this, best kind of spray bottle (if that's the best method), etc.

Thanks,
Drew

Are you taking the glass to fire polish or fusing temperatures? My experience is that the whitish streaks occur when the Spray A hasn't been fired hot enough to melt it properly. You can do this at fire polish temperatures, but every kiln is different so I hesitate to give you a specific recommendation. If you're following the manufacturers instructions and still ending up with streaks, try going a little hotter. Also, apply it thinly and evenly. Using a brush or sprayer are both fine, but I've had better results spraying.

Thanks so much. I fired at full temperature. I think i may have applied too much Spray A. I think spraying it on will be a better choice than brushing it on.

The cheapest device is called a mouth atomizer. Purchase it at an art supply store. It isn't too hard to learn to use this, although it can be described as a cheap thrill. You place the device in a bottle of liquid and blow hard through the mouthpiece, and the liquid sprays out the front of it. I use one for Spray A, borax solution, and kiln wash. The automated version is a Paasche 62 sprayer, which requires compressed air to power it. The principle is the same. Any sort of airbrush also works.

thanks bert

For my borax solution I suck it from the bottle with an eye dropper (to avoid stirring the sediment at the bottom).

Drop a few lines of borax onto the glass and spread it with my finger. No finger marks because the finger is sliding on top of the borax, not touching the glass.

Read about this method somewhere on the Internet. You might like to try it. It sounds too simple to be true, but it works very well.

Regards, seachange

thanks very much. I tried the Spray A and it really didnt work well for me.

Spray A works great, as long as it's mixed really well, applied thinly and evenly (sprayed with a mouth atomizer works best for me), and taken to a full fuse temperature to fully cure (1425° minimum in my kilns).

thanks valerie. I may not be applying it correctly. Perhaps i should look into a mouth atomizer.

Bert,
Sometime ago, I think you mentioned using the Paasche 62 for shelf primer. Does it have any kind of material control other than the viscosity of the material and/or air pressure? I've looked at pictures of the Critter Gun, it looks like the little tip screws up and down. Does anyone know if you can control the amount of material moving this tip up and down? I'm using small stainless forms for draping and, after each drape, I have to give the stainless a quick sandblast and more shelf primer. I do 7 or 8 at a time. Right now, I am using a small air brush, it works but it's slow and I'd like to speed things up.

Terry

Terry Crider wrote:Bert,
Sometime ago, I think you mentioned using the Paasche 62 for shelf primer. Does it have any kind of material control other than the viscosity of the material and/or air pressure? I've looked at pictures of the Critter Gun, it looks like the little tip screws up and down. Does anyone know if you can control the amount of material moving this tip up and down? I'm using small stainless forms for draping and, after each drape, I have to give the stainless a quick sandblast and more shelf primer. I do 7 or 8 at a time. Right now, I am using a small air brush, it works but it's slow and I'd like to speed things up.

Terry

Hi Terry, I use a paint spray bottle attached to the compressor. It has a 1 ltr (approx. 1 quart) container, is easy to use and fast (I do lots of molds of all sizes plus lots of kiln shelves at the same time). Use it outside, saves me cleaning. The bottle is easy to clean after the job is done.

Best regards, seachange.

On the Paasche 62, there is only an on lever. When you pull it back, it blows air over the tube and the liquid sprays out the nozzle. You can adjust the air pressure going in, at your compressor, but that is the only adjustment I know of. It works fine for both overglaze and kiln wash. I make my kilnwash the consistency of skim milk, not heavy cream.