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arthur_ross
03-26-1999, 10:50 AM
I've read a lot of opinions about dust collection systems & grounding for static protection, has anyone seen real published data about "good practices", and what folks out there are really doing for grounding etc.

Arthur Ross/Deltamation Inc./www.signsontap.com

john@pcjet.com
03-26-1999, 03:19 PM
Delta suggests using their wire wound 4" flexible hose. I has been documented that using regular dryer vent, PVC pipe, and even the plastic hose to your shop vac can cause a fire ball. J.E.T. uses a 1500 CFM Delta impeller driven vac that is connected to a 4" metal stove pipe into our shop, then connected to our custom router collar via Delta wire wound flex hose to collect most of our dust and wood chips.

We decided on this setup after reading about some wood working shops that burnt to the ground because they were using PVC (and they had been doing it for years!). The cause of the fire was determined to be a spark from the static electricity charge that builds when the chips and dust pass over the surface of the PVC. It should also be noted that the article stated that a grounding wire strung through the PVC will not safeguard against a spark.

With the Delta wire wound flex hose (25 ft for $10.00) there is virtually no static build-up.

There are other static safe flex hoses, not just Delta.

John
J.E.T. Enterprises

john@pcjet.com (mailto:john@pcjet.com)
www.pcjet.com

robert
07-07-1999, 10:57 AM
I densly wrapped the outside of the pipe with braided copper wire (12 Ga.) and feed another wire through the center of the pipe. The center wire is grounded to the outer wire at every junction as well as the tool(s) in use and finally to a dedicated 8' copper grounding rod outside. Nothing is guaranteed but this is pretty effective. I've actually watched sparks leave the sander and mix with a dust-laden air stream and no fires occurred. Please remember fires often occur in the dust collection devices themselves (i.e. the dust collector bags). Wood can smoulder for days before a visible fire errupts. Empty bags daily!

bullseye@nissan.net
07-07-1999, 12:42 PM
Pardon me, I used 16 Ga wire on the outside and 14 Ga. on the inside. All wire to wire connections were soldered.

ridiss@webgears.com
01-25-2000, 08:16 PM
AS A NEW S/B USER/OWNER.... DOES THIS FIRE POTENTIAL EXIST ONLY WHERE WOOD IS USED, or DOES IT EXIST ON ALL MATERIALS BEING ROUTED??

Phil Pritchard
05-31-2000, 08:16 PM
It is not only wood which can burn. Other materials such as plastics are equally combustible by their very nature. The earlier point about emptying dust bags daily is valid. My shop contains a 5 1/2 hp (3-phase) dust extractor which burned for a while when its previous owners used it to extract sanding dust from plastics. Loosened abrasive particles set fire to the contents of the waste sack after smouldering for a number of hours and resulted in the business partly burning down! What the fire didn't get, the sprinkler system did

MJDreiling@aol.com
05-31-2000, 09:21 PM
As a retiree from a career in the petrochemical industry, I appreciate reports of safety incidents such as the last in this forum, even if they had turned out OK. The description of only minor incidents at your location will help prevent major problems somewhere else.