My belt sander thinks it's a Van de Graaff generator

Either the belt's not at ground or your hands not at ground. Try connecting a wire from your hand to the frame (might want to use a resistor to limit current) and see if the sparks are stopped. If you are grounded and the machine is grounded it is the electrical equivalent of a wire connecting you to ground, the same potential (should be) as power plug ground.

RogerN

You get sparks ONLY when sanding something? The belt is charging up the item being sanded! You need to ground that, too. (Just a guess...)

Is this a hand-held or table-mounted sander?

And, yes, a belt sander really LOOKS like a Van de Graff, so the problem is not too surprising.

Jon

I think the wire from you to the machine is good.

Further grounding of the machine is also advisable. Don't trust the electric power wire.

Christopher A. Young Learn more about Jesus

Either the belt's not at ground or your hands not at ground. Try connecting a wire from your hand to the frame (might want to use a resistor to limit current) and see if the sparks are stopped. If you are grounded and the machine is grounded it is the electrical equivalent of a wire connecting you to ground, the same potential (should be) as power plug ground.

RogerN

that's pretty amusing, like the lightning storm you can get with a C02 fire entinguisher.

You might try adding some type of grounded metal spikes pointing at the surface of the belt in a couple places, as long as they're out of your way.

This would bleed the charged off before it arcs over to you. The pointier and closer to the belt, but not touching the better.

Even a chopped up pop can tin snipped into "spikes" and screwed into something would probably work and cost nothing. Put some bends in the metal so it's ridgid and doesn't flap around, tear off and fly into your face.

Or just wet the belt, if you can.

Get an ohmmeter and test the ground connection between the chassis and the 3rd pin on the plug. Power cords have been known to go bad. Less likely is a faulty ground at the outlet. I assume you are not using a 2 wire extension cord - right? Art

"Artemus" fired this volley in news:kef2tc$ik0$1 @dont-email.me:

There's also the possibility that the non-driven pulley is framed in plastic, and might not be grounded. That's not usually the case, since there's almost always a metal tensioner bar pushing from chassis to pulley.

Lloyd

Google: static electricity shock from belt sander

---- and be prepared to spend an hour or two.

As others have said, an important clue is when it mostly happens on real cold days, when the RH is quite low.

A point that many seem to miss is that it's the action of the belt rubbing the rollers or the backing plates that rips electrons off the BACK of the belt. This leaves the OTHER side of a non-conductive belt deficient, creating the net charge on the side you are using.

We used to make a simple machine called an "Electrophorus" when we were kids, that used this phenomenon to good advantage.

One way we bled off static on a particularly sensitive piece of microfilm equipment was to wipe down everything with a weak solution of Dawn Dishwashing soap. You might just try spritzing a little water into the air around the sander.

Pete Stanaitis

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It's static electricity. My dad had that problem when sanding wood pieces on a 1" Delta belt sander. It only happened in the dry air of winter. We solved it with an anti static wrist strap like this:

Is it practical to run a humidifier? Or, that might create rust problems.

I suspct better grounding of the machine is needed.

Christopher A. Young Learn more about Jesus

It's static electricity. My dad had that problem when sanding wood pieces on a 1" Delta belt sander. It only happened in the dry air of winter. We solved it with an anti static wrist strap like this:

Jim Stewart on Thu, 31 Jan 2013 15:09:38 -0800 typed in rec.crafts.metalworking the following:

Dry air where you are working? - those could be"static" electricity.

-- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."

That's what it is ... charge builds up on the outer surface of the belt, but the belt itself is an insulator so the charge can't easily get to ground until the voltage is high enough to bore through the belt material.

The solution is to add a grounded metal brush that just barely touches the belt. That'll drain off the charge. If it doesn't ... well ... maybe you're not as 'grounded' as you imagine. Get one of those cheapo outlet testers.

My solution is to tap the work on the motor housing to release the charge without feeling a shock. jsw

Won't work. The charge is on the outer surface of the belt, insulated from the motor housing.

This may seem irrelevant, but if you are grinding a lot of aluminum, creating a lot of very fine powder, a serious static discharge may ignite it - and aluminum burns *very* hot.

Most belt grinders have a 'fence', a bar or metal you hold what you're working against. This is where the 'brush' needs to be.

"Mr.B1ack" <

Bullshit! Mg yes, Alum no way.....

I just sprinkled fine aluminum grit from the bandsaw onto glowing charcoal in the stove and watched Nothing Happen.

Even worse if you are alternating sanding aluminum and iron/steel. The iron and steel dust tends to oxidize quickly when that finely divided, and when mixed with aluminum powder, you have a pile of thermite in wherever the dust collects. You really don't want that to light off. :-)

Enjoy, DoN.

I remember hearing something about set the power tool down on the ground, then let go, then pick it back up and begin using it. This will result in the tool being grounded right along with your, and the plug's ground potential.

Yes it does. Aluminum dust is very explosive:

"On the evening of Oct. 29, 2003, a series of explosions severely burned three employees, one fatally, and caused property damage to the Hayes Lemmerz manufacturing plant in Huntington, Ind. The Hayes Lemmerz plant manufactured cast aluminum automotive wheels, and the explosions were fueled by aluminum dust, a combustible by-product of the production process. " (page 5)

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Yeah that was my thought. Any sparks should go to the metal frame of the sander.

George H.