Replies

1. 
   MStehelin | Dec 10, 2002 11:26am | #1

   You know I have yet to hear about any explosion. I think it is a bunch of people covering their asses "just in case"

   Cheers

   Mitt

2. 
   GrahamC | Dec 10, 2002 02:22pm | #2

   I've never heard of an explosion as a result of an earth fault.  Dust explosions are reasonably common where there is a high level of fine, combustible particles in the air, like flour or grain mills, but that is because of open flames or sparks.

   I would be more concerned with getting a shock from faulty ungrounded electrical equipment than being blown up in the workshop.

3. 
   rrwood | Dec 10, 2002 03:20pm | #3

   Another reason to wrap the duct with grounding wire on PVC is to keep from getting "zapped" if you touch the duct work.   The PVC can build up a charge if conditions warrent.  It is more of a personal safety issue.  When a body gets hit with a charge, its natural reaction is to pull away quickly - as a result the person may get injured by a running machine.  I got zapped once while cleaning out the table saw with a shop vac.  Electricity arced to my cheek, laid me on my other cheek.  I was surprised on the amount of current build up.

   Like the others said, I have not heard of any accurence with explosion at a home shop.

   rrwood

4. 
   JeffKurtz | Dec 10, 2002 05:43pm | #4

   I've never heard of an explosion as a result of wood dust, but one of our local papermills makes tissue, and every once in a while they get a dandy big bang in their metal exhaust ducts.  Blows the hell out of the whole system; rips every thing apart.

   Did you ever do the experiment in science class where you take a small amount of flour, put it in a paper sack, shake the sack, then light it?  The thing is like a small bomb! 

   I prefer to err on the side of caution.  Chances are an explosion will never occur, but I'll make sure it doesn't.

   Jeff

1. 
   user-274461 | Dec 10, 2002 08:08pm | #5

   Thanks to all who replied.  This is consistent with what I am hearing as well, especially where most of the material going through my dust collector are chips, not fine dust.

2. 
   PlaneWood | Dec 11, 2002 07:02am | #6

   I've had explosions when using my drill press on Cocobolo!  Very minor - just a barely audible pop and a small whiff of smoke.  The drill gets the cocobolo hot and the oils and the heat and the pressure acts like diesel fuel.  First time it happened it suprised me. Used to it now.    Try it sometimes at high speed with a dull bit.

   The more dry the climate, the more risk there is in dust explosions.  Down here in Houston, I have never been shocked by static electricity in our house.  Happened all the time in OKLA in the winter.

   PlaneWood by Mike_in_KatyPlaneWood

1. 
   JeffKurtz | Dec 11, 2002 03:41pm | #7

   Yikes!  If it had happened on the lathe, it could have been dangerous or at least produced an interesting turning.  I've never worked with Cocobolo, but I have a piece I'm going to use to make a spoke shave.  Anything special other than very sharp tools?

   Jeff

1. 
   PlaneWood | Dec 11, 2002 08:09pm | #8

   Jeff -

   No, Cocobolo is easy to turn.  All that oil lubes it up.

   My Delta midi-lathe is 5 speed.  I have been turning most everything at 2700 rpm.  Couple of days ago, I whooped it up to the last step - 3700 rpm.  Man, what a difference!  Everything I turn is 2" or less diameter so the higher speed is OK.  Less chatter and faster working at 3700 rpm.

   PlaneWood by Mike_in_KatyPlaneWood