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Forum topic by poopiekat posted 01-01-2013 03:12 PM 1735 views 0 times favorited 23 replies Add to Favorites Watch
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5140 posts in 5196 days

01-01-2013 03:12 PM

Topic tags/keywords: question fire grinding sparks

Whenever I grind steel I use a wet rag under the grinder where the sparks hit the bench. Then I start to think obsessive thoughts, like how I dare not leave the house for a few hours, to be sure there isn’t some smoldering ember hidden in the sawdust swept under the bench. Has anyone ever experienced a fire caused by grinding sparks? I mean, not so much where sparks fall into an open container of Naphtha, but under reasonably broom-clean shop floors with some degree of awareness for typical safety procedures.

-- Einstein: "The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." I'm Poopiekat!!

23 replies so far

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933 posts in 4155 days

#1 posted 01-01-2013 03:47 PM

Yes I have at least a couple times since I’m often doing metalworking in my woodshop. I wouldn’t say your wet rag is obsessive just prudent fore thought that many of us don’t always engage.
But I must tell you of one time that could have had disasterious results. I was working with several friends in one friends old barn. We were doing all kinds of work, everybody has different projects going on so there is lots of noise and activity. Well here I am using a 4 1/2” grinder on some metal and I’ve got sparks flying everywhere. Setting a few feet away was a box of fireworks, yup you got it I lit it off. We had all kinds of things making noise then firecrackers, bottle rockets, sky rockets one would ignite another then another. Now with all the noise and my sparks no one really noticed right away but then someoone did and quickly took the box outside and separated things so it wasn’t a total loss in fireworks. Now as I said the was a friends old barn tinder dry with a wooden floor with wide spaces between the boards where much dust and debries collected and you can see how this could have become a disaster. We were lucky and after that we were much more careful. So I feel that you are very prudent.

-- See pictures on Flickr -[email protected]/ And visit my Facebook page -

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5140 posts in 5196 days

#2 posted 01-01-2013 05:50 PM

Thanks, Mike!
I’m about to convert some old files and other iron into scraping tools and lathe tools. Yes, those 4 1/2 grinders really put out the sparks! I’ll be using primarily 6” and 8” grindstones. I just realized there’s no extinguisher in the shop, so I’ll go buy one. If I was working out in the garage it wouldn’t matter so much, but it’s -10 right now and there’s no heat out there. btw, who was brave enough to salvage the unlit rockets while the rest were going off? WOW!!

-- Einstein: "The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift." I'm Poopiekat!!

View REO's profile


929 posts in 3536 days

#3 posted 01-01-2013 11:46 PM

I have never had a fire from grinding sparks. I have tried to set dust on fire with them on purpose. The only place that anything happened was very close to the wheel where the majority of the sparks would hit while still carrying heat(visibly bright) and then I had to carefully blow on them to get them to burn. Even for heavy removal I believe that your wet rag will suffice until it dries out. use a shallow pan with water in it for more security.

View patron's profile


13722 posts in 4803 days

#4 posted 01-02-2013 12:03 AM

this happened to me a couple of years ago


we have all had the occasional “sparks ” ,
last night i was using my new spline jig for box corners ,
with a stacked dado setup ,
and got some sparks where i cut through some light gauge pinner brads .
( they were in the jig itself ) , it’s happened at times in the past ,
and as they are soft and the tools can handle it ,
i didn’t think much of it , and procceded working .
the little smoke , was like the usual dull or hard wood type ,
not to be concerned with to much , just slow down .
and as i was end plowing , i was concerned about tearout .
and more concerned about the safety of this new operation,
i proceded cautiosly along .

but i started thinking the lingering smoke wasn’t thining out as it usualy does ,
and then out of the corner of my eye , i started seeing dancing lite down at the base of the saw .
finish cut and check it out .
as i don’t have a vacumn set up yet , the sawdust piles up at the base of the chute .

wow ! FLAMES ! , inside the saw ! fanned by the wind from the dado blades !
go get the extinguisher , ( i can’t find anything in my shop , but i always know where the extinguisher is )

pull the pin , and to the rescue !
only the extiguisher is dead ! nada !

it’s the stringy saw dust from rip dadoes .
get a stick , and clean it out of the saw .
mound of regular sawdust with flames abounding !

there goes 10 years of building my house and shop !
and i’ll never finish this box !

get some water , and pour it on the flames , 3 trips to the kitchen .
bring one extra , just in case .

back to work, thanks God !

merrily muddleing along , then more smoke ?
now the regular sawdust is like a coal fire , just slowly spreading
inside off the pile , no flames !

o.k. , more water , hand over sawdust , checking , more water .

well , i got it out , and finished the box !
but stayed up 2 hours just to be sure .

now it’s off to the store for more extinguishers .

i am glad i didn’t have a vacumn set up yet , as this would have happened
downstairs out of sight !

is there a spark arrestor for the vacumn line before the collector ?
how does it work ?
where do i find one ?

please work safe , and keep your eyes and nose peeled !

thanks !

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View Joe Lyddon's profile

Joe Lyddon

10963 posts in 5514 days

#5 posted 01-02-2013 12:30 AM


Talking about the Devil! No more than said… and it HAPPENS!!

Yes! Thank you God for taking care of that situation!

Glad you got it, David… the box, I mean… you finished THAT BOX! LOL (kidding)

That would have been horrible!

Happy New Year!

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: ... My Small Gallery:

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3134 posts in 3487 days

#6 posted 01-02-2013 01:36 AM

I’ve had the smolders under my TS after cutting steel with an abrasive wheel (yes, I know it’s not good for the saw—but I hated that saw anyway). Another thing to watch out for is grinding around fine steel wool. It will smolder, gradually burning up the steel wool, and can burst into flame. I’ve learned also not to wear polyester sweatshirts while grinding, as the sparks, especially from an angle grinder, will melt holes in synthetics. Cotton or wool are okay. And I hate cutting aluminum while wearing fleece, as the chips cling like burrs. No fire, but the sticking may be because the chips are hot for a half-second as they come off the saw.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View gfadvm's profile


14940 posts in 4152 days

#7 posted 01-02-2013 03:28 AM

I threw some sparks towards a cotton buff wheel unknowingly. I left to feed the horses and when I came back the shop was full of smoke and the buff wheel was flaming. I have set sawdust on fire with my metal chopsaw as well. Scary! I do have 2 fire extinguishers in my shop and I always am sniffing for smoke before I lock up for the night. I’ve heard that smoke alarms don’t work well in a shop environment as the sawdust in the air will set them off (but can’t verify this).

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

View Dusty56's profile


11868 posts in 5150 days

#8 posted 01-02-2013 04:46 AM

Yup , same healthy fear of a sneaky fire happening from grinding in the shop.

-- I'm absolutely positive that I couldn't be more uncertain!

View Ted's profile


2877 posts in 3673 days

#9 posted 01-02-2013 04:55 AM

I was sharpening a chisel with my belt sander and the dust bag caught fire from the inside. In retrospect, I probably should have removed the bag.

-- You can collect dust or you can make dust. I choose to make it.

View lwllms's profile


555 posts in 4744 days

#10 posted 01-02-2013 05:01 AM

We grind a lot of steel in our shop. I’ve put water proof covers on the electric receptacles so piled up grinding swarf can’t collect on top of an electric plug where it can short things out. We have dust collection to the three grinders used most often but everything goes into a metal drop box/separator before it goes through several feet of clear duct to the dust collector. I’ve never seen a spark get into the clear duct work but I do worry what would happen if sparks made it to the filter. I do know that grinding dust isn’t good for us and we make an effort to control it.

View Dustmite97's profile


439 posts in 4682 days

#11 posted 01-02-2013 05:38 AM

I always have the same fear when sharpening chisels. I get paranoid and always do a thorough clean up around the grinder before I use it.

View Don W's profile

Don W

20389 posts in 4030 days

#12 posted 01-02-2013 01:51 PM

good thread poopiekat. Its always worried me, especially when I’m welding. I try to weld in the empty bay. In the summer I’ll take it outside.

I try to not grind before I leave the shop to.

-- - Collecting is an investment in the past, and the future.

View Cole Tallerman's profile

Cole Tallerman

392 posts in 3647 days

#13 posted 01-02-2013 02:10 PM

I started a fire in my crappy hitachi belt sander. The dust collection was not good at all on it and while deburring a bunch of rods for my homemade jointer, a spark got stuck in a pile of dust. Good thing i had just replaced my non working fire detector. I heard it go off and went downstairs to my shop, and sure enough, alot of the plastic parts on the sander had been melted and there were multiple embers inside. I now make sure that any tool that is used for both metal and wood, gets totally cleaned of dust before I get the sparks going.

View Whitewalls's profile


63 posts in 3436 days

#14 posted 01-02-2013 02:39 PM

I used to be a machinist, and the first shop i worked in wasn’t the cleanest. They had a box of oily rags next to the upright grinder and I was grinding down a piece of steel for a tool I was making and started to smell smoke. damn rags were smokin away.

As for sawdust, I haven’t had sawdust catch per say, but I’ve had an Orbital sander start on fire inside the housing. I never cleaned it out and the only thing I can figure is that with all the friction, it started a small fire in it. Now I clean them out with the air hose.

-- Jared, Northern IL

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4032 posts in 4433 days

#15 posted 01-02-2013 06:33 PM

This is a big concern for me as well. I don’t think your precautions are any thing but being justifiably prudent.

I have started a fire on more than one occasion. Fortunately I never lost control and all were promptly extinguished.

One big surprise for me was what happens to aluminum dust when it is bombarded by iron sparks. Hint, remember those old flash pictures where the photographer had a tray of some flash powder. I think I determined how that powder is made. I made a flash tray about 18” wide and 12 feet long; without knowing what I was doing till I set that sucker off..

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