What has gone wrong (sandblasting) here?

This is the main board for discussing general techniques, tools, and processes for fusing, slumping, and related kiln-forming activities.

Moderators: Brad Walker, Tony Smith

Post Reply
Ron Bell
Posts: 45
Joined: Wed Mar 12, 2003 12:31 am
Location: Middleburg, Florida

What has gone wrong (sandblasting) here?

Post by Ron Bell »

All of a sudden my sandblaster is blasting large (relative) chips out of the glass I am blasting. I'm not sure what has changed since I am now on about the 40th piece all done the same. I have replaced the nozzle, added grit, checked for water in tank and generally used a lot of foul language. Could it be....
1 - Grit getting contaminated (silicon carbide 80#)?
2 - Bad batch of glass (black irid)?
3 - Something like....
Or a dumb operator who doesn't see the obvious which is.....

All suggestions welcomed and appreciated!
Ron Bell
Black Creek Glass
Tony Smith
Posts: 1037
Joined: Sun Mar 09, 2003 5:59 pm
Location: Massachusetts, USA
Contact:

Post by Tony Smith »

This is a new one on me. You haven't been crushing your own grit out of rocks? Have you? :shock:

Try emptying your grit and sifting it through a screen... a regular window screen should be sufficient. I can't imagine that your abrasive is sticking to itself and forming small rocks, but that's what it sounds like. The fact that it's getting through the nozzle is also surprising. The screen should sort it out.

Also, make sure you drain your water trap as, this time of year, moisture can be a real problem.

You may be firing small bits of glass at your glass, but the screen should take care of that as well. It's a good idea to screen your abrasive every time you fill your pressure pot, or periodically if you use a siphon blaster. It eliminates a lot of problems later.

Tony
The tightrope between being strange and being creative is too narrow to walk without occasionally landing on both sides..." Scott Berkun
Ron Bell
Posts: 45
Joined: Wed Mar 12, 2003 12:31 am
Location: Middleburg, Florida

Post by Ron Bell »

Tony - Thanks for the suggestion. I'm going to dump the grit and screen it this weekend. At this point I hope I find big chunks of something.

Thanks again!
Ron Bell
Black Creek Glass
Darrin Strosnider
Posts: 16
Joined: Tue Mar 11, 2003 10:33 am
Location: Desert Southwest

Re: What has gone wrong (sandblasting) here?

Post by Darrin Strosnider »

Ron Bell wrote:All of a sudden my sandblaster is blasting large (relative) chips out of the glass I am blasting. I'm not sure what has changed since I am now on about the 40th piece all done the same. I have replaced the nozzle, added grit, checked for water in tank and generally used a lot of foul language. Could it be....
1 - Grit getting contaminated (silicon carbide 80#)?
2 - Bad batch of glass (black irid)?
3 - Something like....
Or a dumb operator who doesn't see the obvious which is.....

All suggestions welcomed and appreciated!
Ron- you didn't say anything about the air pressure. Is your pressure at the compressor still the same, as well as the setting on the ratio mixing valve (if you have a pressure pot)?

Tony's suggestion for straining again is on the money. Once you blast a "chunk" of glass out- it has to go somewhere. It's possible that you are firing those chunks at your ware now, and creating even more chunks to fire... :shock:

-stro
Post Reply