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new sandblasting Question.

Posted: Sun Mar 21, 2004 11:46 pm
by jim simmons
I just got my sandblaster up and running. Am using 180 grit silicon carbide,
and noticed that sometimes where the sand hits the target surface, there is a glow somewhat like a dim light bulb. Could this be localized heating or would it be some kind of electrical discharge?

Just qurious.
Thanks.
Jim

Posted: Sun Mar 21, 2004 11:54 pm
by Clifford Ross
HEY SPARKY !!!-- install a ground wire. :shock: :shock: :shock: :shock:

Posted: Mon Mar 22, 2004 2:18 am
by Nickie Jordan
Hey Jim,
Isn't it interesting ? I believe silicon carbide is the only one that has this character. It helps to see your blast pattern as you are moving along.
I have never , ever had a problem with shock with this abrasive.
Glad you're up and blasting !
- Nickie

Posted: Mon Mar 22, 2004 7:58 am
by Don Burt
I've found that if you tape the top of your head with shiny HVAC metallic tape that they aren't able to install their mind virii while you're blasting with that stuff. I thought about using a high-lead content solder and making a helmet, but thats probably overkill. Keep your eyes open though.

Posted: Mon Mar 22, 2004 10:26 am
by Brock
Don Burt wrote:I've found that if you tape the top of your head with shiny HVAC metallic tape that they aren't able to install their mind virii while you're blasting with that stuff. I thought about using a high-lead content solder and making a helmet, but thats probably overkill. Keep your eyes open though.
Yeah! And look out for crop circles. And crowns of thorns. Mel

Re: new sandblasting Question.

Posted: Mon Mar 22, 2004 10:38 am
by Phil Hoppes
jim simmons wrote:I just got my sandblaster up and running. Am using 180 grit silicon carbide,
and noticed that sometimes where the sand hits the target surface, there is a glow somewhat like a dim light bulb. Could this be localized heating or would it be some kind of electrical discharge?

Just qurious.
Thanks.
Jim
The glow is the glass being blasted from the surface. It has nothing to do with electrical discharge. If you look close and practice you can use this as a gauge to how your are proceeding to remove glass from the surface and to direct you when you are on and off the surface of the glass.

Phil

Posted: Mon Mar 22, 2004 12:39 pm
by jim simmons
Nickie Jordan wrote:Hey Jim,
Isn't it interesting ? I believe silicon carbide is the only one that has this character. It helps to see your blast pattern as you are moving along.
I have never , ever had a problem with shock with this abrasive.
Glad you're up and blasting !
- Nickie
Hi, Nickie. I used to work in the semiconductor industry, and we did a lot of sand blasting with SiC, and also I have never recieved a shock. I was just currious what this phenomenon was.

BTW. my cabinet is grounded and I wear a wrist strap that is connected to the cabinet.

I also responded to you off line.
Jim

Re: new sandblasting Question.

Posted: Mon Mar 22, 2004 12:44 pm
by jim simmons
Phil Hoppes wrote:
jim simmons wrote:I just got my sandblaster up and running. Am using 180 grit silicon carbide,
and noticed that sometimes where the sand hits the target surface, there is a glow somewhat like a dim light bulb. Could this be localized heating or would it be some kind of electrical discharge?

Just qurious.
Thanks.
Jim
The glow is the glass being blasted from the surface. It has nothing to do with electrical discharge. If you look close and practice you can use this as a gauge to how your are proceeding to remove glass from the surface and to direct you when you are on and off the surface of the glass.

Phil
Thanks for the INFORMATIVE answer, Phil. I really appreciate it.
Jim

Posted: Mon Mar 22, 2004 8:10 pm
by Tony Smith
Many sandblasters refer to this as a flashlight effect. It only occurs with silicon carbide and is the result of the crystal fracturing... much like when you bite into a wintergreen lifesaver.

Tony

Posted: Tue Mar 23, 2004 11:53 pm
by elin
I find the "flashlight effect" very useful! It helps me see where I am blasting. I think that's what I like best about silica carbide.

However, I have experienced something else that led us to ground our nozzle and glass rack. We had a few pieces of glass ruined by a "lightning bolt" shock. It looked sort of like a lightning bolt going through the thickness of the glass-- didn't crack it or anything, persay... but we were uncertain what the outcome would be... It occured when we were blasting the area directly in front of the metal glass rack. And even though the glass was a 1/4" or so away from the rack, it sent an electrical shock through it. I think we were even using aluminum oxide at the time. It hasn't happened since we grounded the nozzle and the rack. Has anyone else had that happen?
-elin

Posted: Wed Mar 24, 2004 12:35 am
by Tony Smith
Aluminum oxide will do that... it develops a tremendous static charge when it passes through the hose. It can certainly start you twichin' if you weren't twichin' before.

Tony

Posted: Wed Mar 24, 2004 2:26 pm
by elin
So, Tony,
I have definately felt the electricity before, but have you ever seen the lightning bolt effect that I was describing? It actually goes through the glass, like a crack of sorts... There is a small flash of light when it happens, but then there is a "crack" that remains in the glass. It was quite the novelty in our circle, but it happened a few times. I'm curious if it is a common occurance.
-elin

Posted: Wed Mar 24, 2004 2:29 pm
by Brock
I've never seen that and have done years of commercial art blasting.

However, everyone around here uses wooden racks. Brock

Posted: Wed Mar 24, 2004 3:54 pm
by Marty
I'm also using 180 SiCarbide- I find that flash useful when blasting if the power goes out.

Seriously, apropos of sandblasting- I put a chunk of Home Depot rubber floor matting on the shelf in the cabinet- cushions the glass and lets the grit fall through. Lining the inside walls with tan rubber carpet underlay stuff also helps prevent chipping glass from enthusiatic handling and accidental spray from eating into the paint.

Something wrong with the syntax in that paragraph...

Do you-all pay syntax?

Posted: Wed Mar 24, 2004 6:13 pm
by Tony Smith
elin wrote:So, Tony,
I have definately felt the electricity before, but have you ever seen the lightning bolt effect that I was describing? It actually goes through the glass, like a crack of sorts... There is a small flash of light when it happens, but then there is a "crack" that remains in the glass. It was quite the novelty in our circle, but it happened a few times. I'm curious if it is a common occurance.
-elin
No, I've never seen a lightning bolt pass through the glass... are you sure you don't have some untapped powers?

Tony

Posted: Thu Mar 25, 2004 12:41 am
by elin
are you sure you don't have some untapped powers?
he he... hmmm... maybe I should look into that... I could probably find a way to use it to my advantage!

I wish I had a picture of this phenomena, but it was a couple of years ago. It's so bizarre to me that no one else has ever heard of or seen it. I guess if it's uncommon to use a metal rack though, that would pretty much explain it... If I can find the piece of glass, I'll take a pic and post it.