Could have been a disaster!

Grinders & Dust Collection

Steve Elliott

We had a fire at a shop I worked at that was caused by grinding sparks being sucked into a dust collector. The shop was in an old wooden warehouse that luckily had sprinklers installed. By the time the fire department arrived the sprinklers had put out the fire, but it was pretty dramatic for a little while.

Any dust collector used with wood will have plenty of flammable bits in it and the air flowing by can fan a spark into a fire very quickly.

Glad your fire was put out right away.

I Never Ever Everrrrrrr

Mark Mandell - Gone Round In New Jersey

Put steel to a grinder or sander that's connected to any kind of DC, beit a shop vac, a cyclone, or something in between.

Glad you escaped the consequences!

I run..

David Weaver

Copious amounts of metal sparks into a clear cyclone and then into a trash can. But I've never seen a visible spark even get to the cyclones, let alone through it to the can.

Re: I run..

Bill Howatt

I don't know enough to say if what you are doing is safe or unsafe but I do try to follow the adage:

Just because you done something with out consequences a 1000 times doesn't mean it's safe on the 1001 time!

Bill

You Forgot To Add

Mark Mandell - Gone Round In New Jersey

"Hold ma beer, Bubba, while I do this,"

What you really meant....

John in NM

"Hold my beer bubba, I have to go hide in a closet for fear that the internet's idea of safe behavior is reflected by reality!"

Lighten up a bit guys

I bet....

John in NM

The difference is in the grit size of the abrasive Barry was using vs what you use. Bigger grit means bigger hot particle, more mass, more momentum, more capacity to carry heat from the wheel or belt off to the piles of dust that litter our shops (and vacuum bags in the shops better regulated than my own).

Just a quick theory. Could be you're using the heavier grit and I'm all wet like Barry's vacuum bag!

Re: I bet....

J Barrett Irby Jr

You are correct. The first time I did this I had a fine belt, maybe 120 grit on the sander and it worked well. This time it was something like 60 grit. That may have been the problem. Interestingly, I had cleaned the shop to the point of trying to blow it out with a leaf blower. But, there was an accumulation of dust inside the sander in spite of it being attached to a shop vac.

I had one more chisel to do so I did it without the shop vac thinking there was less chance of sucking a spark into the sander. At that point I had blown out the sander pretty thoroughly so there was no fuel in it.

Interesting idea about the size of the grit/sparks. I should have changed the belt to a finer one just to get a better finish but I was too trifling.

clarification..... safe...

David Weaver

If I have a tool that's sparking and there is dust collection, the tool is not a wood and metal and wood and metal tool, it's metal only.

I don't sand much woodworking, so my sanders are for metal work only. The run of hose that the sparks go through doesn't mix metal and dust. That's extremely unsafe - especially if there's a chance of both going through at the same time.

I just ground some bolsters on chisels with a purple belt that runs 4800 feet per minute (36 grit). The spark coming off is so coarse that it was landing on my feet (not wearing socks) and I could feel it burning and smell it burning. I moved my feet. If those sparks were going into a machine that had wood dust, there's almost no chance they wouldn't create smoke at a minimum. Even when they hit each other where a pile of swarf collects, they fuse to each other a little bit.

I hadn't thought that much about the cyclone until this came up - the reason I'm using it (and there *is* wood dust in the barrel below it), is because I don't want all of the black dust going straight through to the shop vac and clogging it right away. The small dust deputy that's no good for anything more than a sander is excellent for metal dust - it'll swirl the spark around that goes through a 10 foot hose for a while before it's allowed to either drop into the can or the little bit of it that makes it's way past and gets to the vacuum.

I can say for sure also that a flat belt that I have that runs only 2200 feet per minute will literally allow the spark to burn the plywood table that the machine is on, so I leave a cushion of metal swarf under the bottom of the belt where the spark is directed - otherwise the ply table top will capture spark and a ribbon of smoke is the result (stinky).

The way I'm doing things is safe. using a dust capture system on the same tools that I have with wood dust around the machines or in line somewhere, definitely not.

Worked at a cabinet factory when I was in college, and the year before I'd gotten there, someone swept screws into one of the capture points and it started a fire as it sparked through the metal dust lines with the wood dust coming through at the same time. Bad situation.