Bench grinders and fire safety

For starters, you seem to already know the answer. Control the dust. Keep the area clean, keep the air clean, and you should have no problems… Sounds like it is time to hone the shop cleaning skills a bit…

-- Manufacturer of fine quality sawdust since 1984. Comments and advice on my shop welcome. Check it out at http://lumberjocks.com/dbhost/workshop. Gladly accepting shop build donations!

I’ve got two hand-crank grinders and I love them – non-electric, variable speed, portable, noise-friendly.

-- 温故知新

You are right to be concerned about this and, as dbhost suggested, you already know the answer.

My grinder is in an area of the shop that is less prone to have much sawdust. Also, it is not a coincidence that I have a fire extinguisher very close to my grinder. I’ve never had to use it and I hope I never do, but I take some comfort in knowing that it is there (and knowing that it is properly charged).

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

I should mention, I figured the answer out the HARD way. I didn’t have a fire, but I DID have a small smolder on the bench the grinder was mounted on. The burn mark is still there… KEEP IT CLEAN!

Generally speaking, you want no dust, or very little dust within 5 feet of the grinder wheel / path the sparks will take…

-- Manufacturer of fine quality sawdust since 1984. Comments and advice on my shop welcome. Check it out at http://lumberjocks.com/dbhost/workshop. Gladly accepting shop build donations!

I’ll give you a dollar if you can start a fire with a bench grinder.

I’ve done welding brazing metal abrasive saw cutting and grinding for years and years and years in my dusty dirty never swept shop and never has a trace of smoke.

Just don’t put your grinder right next to the chips.

-- When the moderator chooses sides, his site sucks.

When would you like to send that dollar?
I once shaped a piece of aluminum on the grinder.
Then cleaned the wheel and went on about my business..
A couple days later I went to grind some steel and whoosh; the whole frigging bench lit up like a flash bulb.
It caught some sawdust on fire next and I had to use an extinguisher to put it out.
Aluminum dust and iron dust don’t mix well I learned.

-- Michael :-{| Diapers and politicians both need to be changed often; and for the same reason.

Been there done that with a stationary belt/disk sander, grinding chisel bevels. I cleaned up around the machine but didn’t think to remove the cover and clean out inside the machine. I noticed a little plume of smoke, thought the sander was overheating, switched off, more smoke, rapidly unscrewed the cover plate at the end of the sander to find the whole dust outlet area full of compressed fine dust, burning. Melted a bit of the plastic cover and was starting to melt the power cable.
Now I clean her inside and out before grinding metal parts. You shouldn’t have that problem with a grinder, but certainly don’t shower sparks over any accumulated dust, clear it up :)

OK, on a slight tangent, what fire extinguisher class should you keep in a garage shop? Should I just get an ABC class one? My concern is I want to put out any potential fire but not destroy the tool in process. putting out the fire is the first priority I know but it would be nice to not have to screw up the tool too.

-- - Dave ; Austin, TX

Funitude, I hope this isn’t looked at as a hijack, but Crank can you expand on what happened to you. I am uneducated when it comes to metal working, but a find myself doing more and more. I have worked on both steel and aluminum (recently) on the same grinder. What am I trying to prevent exactly?

-- StevieP ~ Micheal Tompkins - you were not here on earth long but left a giant mark on us. RIP Brother

I use a Jet wet sharpener in my shop all the time and have never had any trouble.

http://www.amazon.com/Jet-708015-JSSG-10-Speed-Sharpener/dp/B000LE22EM

-- Beth, Oklahoma, Rambling Road Designs

Send me a dollar also. I set a buffing wheel on fire with sparks from the bench grinder. Don’t hang your buff wheels behind the bench grinder as the wax in the buffing compound burns well. Fortunately, I was in the shop when the wheel stopped smoldering and started flaming or it would have burned my shop down!

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

Steviep,
Sparklers are made of a mixture of aluminum and iron powder. Magnesiun is even more volitile than aluminum and can ignite on its own.

I had left very fine aluminum dust (powder) on the bench and it was mixed with some other iron dust that was already there. When I next started grinding iron, lawn mower blade I think, it was throwing some serious sparks onto the aluminum/iron dust that was there. The mixture ignited with a huge flash. It singed the hair on my arm. Stuff reacted almost like gunpower, or flash powder.

I think what is happening is the large surface area of the aluminum oxidizes and causes the iron to burn, like what happens in an oxygen cutting torch.

-- Michael :-{| Diapers and politicians both need to be changed often; and for the same reason.

”I once shaped a piece of aluminum on the grinder.”

Aluminum Oxide is used in explosives. why on earth were you using Al on a grinding wheel?

Aluminum loaded in the wheel can expand in response to heat and cause cracking in the wheel.

Aluminum also gets forced into the grains of the wheel and the continued use forces it in further which causes the aluminum to act much like water does during a freeze in a rock. It can cause the wheel to shatter under load.
So there’s two ways aluminum can cause your wheels to blow up while you are using ‘em.

A shattered grinding wheel is never a happy moment. I’ve blown up my share of big wheels. Largest was a 10”x 2” Norton on a surface grinder. That made me popular in the shop.

Aluminum cuts so easily and nicely with a file and abrasive belts that there’s no reason to risk losing your grinder wheels.

When I was in the machine tool trade we had wheels for aluminum that were made from shale. They break down much faster and don’t load up.

Test your wheels by holding by the hole and pinging them with your knuckle. they should ring.
If they don’t ~ ~ ~ ~ ~ ~ ~ ~ Uh Oh.

Two friggin Dollars I gotta give away~!!
GEEBUS

TWO Dollars ??~~!!!!~

-- When the moderator chooses sides, his site sucks.

Hi:
I took a piece of Flashing material (Alum.) and folded it up and Pop riveted it together. Mine is dual stones. I folded kinda like a triangle, folded the ends. Cut two slots, and open them up to fit the discharge holes on the grinder. Pushed on and they stay in place. Pull it off to dump. All the sparks stay inside and no FIRE. Works Great