 A Strange Sand Blasting Experience, has this ever happened to any of you |
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| 76-914 |
 Dec 4 2011, 01:48 PM
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#1
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Repeat Offender & Resident Subaru Antagonist  Group: Members Posts: 13,502 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California 
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Alright an update is in order. I have evolved from water heater boxes to a real blaster box. So yesterday it was drier than Tommy Chong's mouth while I was blasting a few pieces. I noticed that I was getting hundreds of little voltage zaps thru the gloves. (IMG:style_emoticons/default/WTF.gif) I think it is static discharge but I'm not sure. I ran a ground wire from the cabinet to a copper pipe but it did not help. So I just bit the bullet and finished. ( I felt like that idiot radioman on the sub in that Kelsie Grammer movie (IMG:style_emoticons/default/lol-2.gif) ). In retrospect should I have stood on a rubber mat, instead. The cabinet is insulated from the metal stand by a piece of plywood, also. Should the wood be removed? (IMG:style_emoticons/default/confused24.gif) Any thoughts?
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| toolguy |
Dec 4 2011, 02:02 PM
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#2
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Senior Member Group: Members Posts: 1,268 Joined: 2-April 11 From: San Diego / El Cajon Member No.: 12,889 Region Association: Southern California
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With a meter, read the voltage from the cabinit to ground first. . Is your exhaust fan motor attached to the cabinet. .if there is no standing voltage, try blasting without the fan on and see if the discharge is gone. . If you have this on a GFI circuit, it should have tripped if the motor was at fault, or possibly you're not bonded to the electrical ground back at the main panel. .
Can't imagine standing there getting shocked. . that's like asking the Lord to strike you down with a giant bolt of lighting. . Can you imagine the little article they'd stick on page 2 about the home garage mechanic who was electrocuted? Maybe God is giving you a hint. . . |
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| Mark Henry |
Dec 4 2011, 02:22 PM
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#3
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
My bet is on static discharge, are you using a shopvac with a plastic hose?
Does it zap you when you were a kid when you shuffled you feet on a carpet? Also the blasting action itself creates a static charge. http://www.woodweb.com/knowledge_base/PVC_...collection.html |
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| stugray |
Dec 4 2011, 02:25 PM
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#4
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Advanced Member Group: Members Posts: 3,824 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None |
Definitely static.
If you were nearby, I would just give you a static dissipating wrist strap. It is like a leash on me at work, never touch anything without one. One thing that might help: Put some copper or aluminum tape around the nozzle and a few inches back on the hose (where you grab it). Then run a ground wire to earth ground. Stu |
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| Jake Raby |
Dec 4 2011, 05:21 PM
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#5
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
This happens all the time when blasting.. Put a ground wire inside the glove and connect it to the cabinet... I have even made a grounding bracelet in the past for overcoming this challenge... I was going to patent it but other art was too similar to it.
The key is grounding yourself to the cabinet.. Standing on rubber just keeps you charged up like a capacitor for ESD at a later time.. |
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| 76-914 |
Dec 4 2011, 05:41 PM
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#6
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,502 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California
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Thx guys, your all spot on except for that part about God talking to me. He's trying to avoid me. I'm always asking him for something. Yes Mark, I do have a shop vac w/ plastic hose attached. Does that increase the area of charged particles? And thanks for the tip Jake. I'll attach the ground wire to my wedding ring.
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| charliew |
Dec 4 2011, 11:45 PM
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#7
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Advanced Member Group: Members Posts: 2,363 Joined: 31-July 07 From: Crawford, TX. Member No.: 7,958 |
I have a big cabinet that I made from 3/4 plywood so I could get motorcycle frames and big stuff in it. It's lined with sheetmetal. I used the parts from scatblast including their dust collector and their biggest window. It has a angle iron frame stand that the bolts go through the plywood but not the sheetmetal. I've never had a static problem. I've used both my friends factory cabinets and haven't had a static problem there either that I felt or saw. I did see something neat the last time I blasted though. I was blasting old chrome on some tractor parts and it gave a real neat glow till the chrome layer was off. It also happened on a chrome lined ram end for a hydraulic cylinder.
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| Jake Raby |
Dec 5 2011, 07:08 AM
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#8
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
The ESD is greatly dependent upon the atmospheric conditions as well as the media that's being used... This time of year it's always worse in my units.
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| Mark Henry |
Dec 5 2011, 08:33 AM
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#9
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
The main reason factory cabinets do not suffer this problem as bad is they have the vacuum system mounted on the unit or beside plumbed with metal ducting. Thus the whole system is grounded together. I wouldn't be surprised if commercial unit also had a ground wire running up the hose to the gun.
Not a big issue in sandblasting, but huge in woodworking. Dust collecting systems in large woodworking operations are a known fire hazard due to static discharge igniting the highly flammable wood dust. This is the reason big commercial wood dust collectors are outside the building and metal ducting is code. It's not a huge problem with small (hobby) wood dust collectors due to small volume, but I always empty mine the same day I use it. |
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| 76-914 |
Dec 5 2011, 08:51 AM
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#10
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,502 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California
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QUOTE(charliew @ Dec 4 2011, 09:45 PM)  I have a big cabinet that I made from 3/4 plywood so I could get motorcycle frames and big stuff in it. It's lined with sheet metal. I used the parts from scatblast including their dust collector and their biggest window. It has a angle iron frame stand that the bolts go through the plywood but not the sheet metal. I've never had a static problem. I've used both my friends factory cabinets and haven't had a static problem there either that I felt or saw. I did see something neat the last time I blasted though. I was blasting old chrome on some tractor parts and it gave a real neat glow till the chrome layer was off. It also happened on a chrome lined ram end for a hydraulic cylinder. Charlie, I used to live close to you (Taylor) and I'd bet the humidity is a factor. I love TX, the people and the food but I don't miss the weather. That glow sounds like St. Elmo's fire. QUOTE(Jake Raby @ Dec 5 2011, 05:08 AM) The ESD is greatly dependent upon the atmospheric conditions as well as the media that's being used... This time of year it's always worse in my units. What's ESD, Jake? "electro _____ _____"? QUOTE(Mark Henry @ Dec 5 2011, 06:33 AM) The main reason factory cabinets do not suffer this problem as bad is they have the vacuum system mounted on the unit or beside plumbed with metal ducting. Thus the whole system is grounded together. I wouldn't be surprised if commercial unit also had a ground wire running up the hose to the gun. Not a big issue in sandblasting, but huge in woodworking. Dust collecting systems in large woodworking operations are a known fire hazard due to static discharge igniting the highly flammable wood dust. This is the reason big commercial wood dust collectors are outside the building and metal ducting is code. It's not a huge problem with small (hobby) wood dust collectors due to small volume, but I always empty mine the same day I use it. Now it makes sense. I don't know why the smallest things overtake my minimalistic mind. |
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| Mark Henry |
Dec 5 2011, 08:58 AM
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#11
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
QUOTE QUOTE(Jake Raby @ Dec 5 2011, 05:08 AM) The ESD is greatly dependent upon the atmospheric conditions as well as the media that's being used... This time of year it's always worse in my units. What's ESD, Jake? "electro _____ _____"? Fancy abbreviation for "electrostatic discharge". |
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