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sandblasting dissipate?

Posted: Sun Jan 16, 2022 5:47 pm
by Bonnie Rubinstein
Hi all,
I usually sandblast the back of my glass as last step. But this time I may need to blast prior to slumping, which happens at 1150 degrees. Can I assume that the blasting I did will remain in tact when I slump at that temp?

Thanks!

Bonnie

Re: sandblasting dissipate?

Posted: Sun Jan 16, 2022 6:02 pm
by Brad Walker
You'll get a matte finish. Exactly how matte depends on the grit used during the sandblasting, the temperature, and the hold time.

Re: sandblasting dissipate?

Posted: Sun Jan 16, 2022 8:38 pm
by Bonnie Rubinstein
well, it is for a light sconce, so I need the frosting to be a good one. Maybe I won't risk it, and blast later.

Thanks you.

Re: sandblasting dissipate?

Posted: Tue Jan 18, 2022 2:37 am
by Buttercup
Here are some notes I copied from various sites, some from here:
SANDBLASTING & CARVING

1. To fire polish sandblasting clear fire to 1400° F.

2. To fire polish and retain the frost fire to 1238° F.

http://www.lampworketc.com/forums/archi ... 81201.html


Glass fusing made easy
Spectrum usually polishes at about 1300 and Bullseye at about 1325.
Temperatures that are high enough to polish are also high enough to distort the edges of the glass, so stay at the polish temperature for only a short time.
Remember, you will want to polish an item while it is flat, before you try slumping the glass into or over a mold.
A suggested schedule would be:

400 degrees per hour to 1000 and hold for 20 minutes
As fast as possible ramp up to 1300 and hold for 5 minutes
As fast as possible ramp down to 950 degrees and hold for 60 minutes
Then down to 400 degrees per hour to 100 and turn the kiln off.

As you can see by this schedule, there are times to go fast and times to go slow.
You will get best results by fire polishing fused glass before you slump the item into a mold.

Hope that helps, Bonnie.

Re: sandblasting dissipate?

Posted: Wed Jan 19, 2022 11:51 am
by Bonnie Rubinstein
Thanks for all that info. very helpful.
I opted to slump, then blast. Unfortunately, I blast outside, and now it will be frigid temps now for a while ( it is zero right now).. so have to hold off on the blasting. In reading your post, I see I could have blasted flat, and then slumped, as I only went to 1150, and the frosting would have remained.

Re: sandblasting dissipate?

Posted: Fri Feb 04, 2022 12:04 am
by Buttercup
Hope it works out, Bonnie. Let us know if you decide to firepolish the frosting and if that affects the shape of the slumped piece.

Re: sandblasting dissipate?

Posted: Fri Feb 04, 2022 1:18 pm
by Bonnie Rubinstein
I decided to slump, then sandblast. I did not want the slumping to minimize the frost, so waited till that was done. We had to do a quick blast outside in frigid temps for that, though!