Bench grinders and fire safety

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Forum topic by Furnitude posted 10-07-2011 05:04 PM 4821 views 0 times favorited 12 replies Add to Favorites Watch
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380 posts in 3507 days

10-07-2011 05:04 PM

Hello all,
I’m thinking about buying a grinder for tool sharpening. Since my shop is in my basement and since my shop cleaning skills are not as advanced as my shop dirtying skills, I’m concerned about sparks smoldering in saw dust and causing a fire. While my first defence would be to sweep up and eliminate most of the dust in the area of the grinder, I wanted to ask what else I could do. Please let me know if you’ve been concerned about this and how you’ve addressed the issue.

-- Mitch, Also blog at

12 replies so far

View dbhost's profile


5712 posts in 3232 days

#1 posted 10-07-2011 05:10 PM

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…

-- Please like and subscribe to my YouTube Channel

View hObOmOnk's profile


1381 posts in 4127 days

#2 posted 10-07-2011 05:14 PM

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

-- 温故知新

View richgreer's profile


4541 posts in 3074 days

#3 posted 10-07-2011 05:20 PM

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.

View dbhost's profile


5712 posts in 3232 days

#4 posted 10-07-2011 05:25 PM

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…

-- Please like and subscribe to my YouTube Channel

View crank49's profile


4030 posts in 2970 days

#5 posted 10-07-2011 07:16 PM

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.

View jeth's profile


262 posts in 2837 days

#6 posted 10-07-2011 07:27 PM

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 :)

View MashMaster's profile


134 posts in 2660 days

#7 posted 10-07-2011 09:09 PM

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

View steviep's profile


233 posts in 2646 days

#8 posted 10-07-2011 10:11 PM

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

View rrdesigns's profile


531 posts in 3185 days

#9 posted 10-07-2011 10:18 PM

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

-- Beth, Oklahoma, Rambling Road Designs

View gfadvm's profile


14940 posts in 2690 days

#10 posted 10-08-2011 03:56 AM

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

View crank49's profile


4030 posts in 2970 days

#11 posted 10-08-2011 08:31 PM

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.

View Bigrock's profile


292 posts in 2962 days

#12 posted 10-09-2011 03:23 AM

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

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