Could Be Fatal

[mpc]

I need to get another extinguisher; now that I live in a house with a detached garage/shop there is no "close to everything" spot for my existing extinguisher.

As for the steel + aluminum grinding thing... I remember a warning similar to that for metal cutting chopsaws. Many use an abrasive disk rather than a toothed blade to cut. What I remember reading is that once a disk has been used on iron (including steel) or aluminum, it should be labeled so that it never gets used on the other metal - specifically because it will have small bits of the first material lodged in it risking a thermite reaction. I use the same logic on grinding wheels. Abrasive disks & grinding wheels are cheap enough to have two; they're not places to penny-pinch and risk metal interactions! Plus, those flying sparks and tiny bits of hot metal from chopsaws and grinders find all sorts of cracks to shoot through looking for rags, paper, etc. to ignite.

mpc

[Tom Slick]

I'll add a little "fuel to the fire".
You won't go wrong with an ABC but there is a reason all fire extinguishers aren't ABC. Make sure to read why certain extinguishers are used on certain fires. A Co2 only (BC) extinguisher will spread sawdust, paper, and other lightweight flammable materials around and potentially cause the fire to get worse, the same way using a water only (A) extinguisher on a grease fire spreads the fire.

From experience you can, but don't want to, use a dry chemical (ABC or BC) on a small engine fire. The dry chemical makes a mess of the engine and is potentially damaging if the engine ingests it. If the fire is big enough then obviously a dry chemical type extinguisher is going to save more than it is going to damage. Although not technically correct, a garden hose is the best way I've seen to put out a small engine fire, like a backfire that catches the carburetor on fire.

Remember PASS

P pull the pin
A aim the nozzle
S squeeze the handle
S sweep across the base of the fire while walking toward the fire

Sweeping the base of the fire is very important to be effective. Spraying at the flames themselves will waste a lot of your precious and very finite fire extinguisher with little effect.

You should also inspect your extinguisher at least once a year. Check the gauge and if it is a dry chemical type (BC and ABC) turn it upside down and shake it to make sure the powder is still loose. Believe it or not the powder can pack down and not come out when you need it.

[LCHIEN]

Grinding aluminum on a stone wheel is not a good idea, apparently. There's mixed opinions on this I read on the internet but I was taught young not to grind aluminum on a stone wheel. There's two issues, one the aluminum dust mixed with other dusts can be extremely flammable with hot dangerous fires as has already been outlined. The other issue is of loading up the stone wheel with aluminum particles. Aside from ruining the wheel's performance, continued use of a loaded wheel can cause the wheel to fly apart.

Not everyone seems to believe this but it appears to me that there's enough to make it worth following.Where there's smoke there's fire. Use a proper abrasive wheel (like silicon carbide) for non-ferrous (like aluminum) grinding or polishing.

Norton Abrasives has the following safety bulletin:
http://www.nortonindustrial.com/uplo...er%20Wheel.pdf


as for extinguishers, the common ABC type seems appropriate for 99% of home use. The powder types are corrosive as someone has pointed out, might not be an issue if there's already serious smoke and heat damage. Halon extinguishers are the best for ABC fires because they don't do collateral damage and are extremely effective on electrical fires. They were expensive and production was ceased in 1994 due to ozone depletion properties of halon. However existing stocks are still bought and recycled and legal to use - very desirable for high value installations such as aircraft and data centers. If you've still got a halon extinguisher that's charged... keep it!

[cabinetman]

While fires can be started from a variety of sources, one of mine was from a spark from cutting hardwood on the TS. This was before DC, and the floor inside the Unisaw collected sawdust, and after several hours there could be a nice little pile.

After several minutes (I'm guessing about 5-10) of cutting, I noticed smoke emitting from the cabinet. There it was, the perfect kindling that finally ignited. No real damage other than some scarring of the outer casing of the wires that hung down.

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[chopnhack]

While fires can be started from a variety of sources, one of mine was from a spark from cutting hardwood on the TS.

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Several years back I had a small fire in my BT caused by my shopvac drawing air across an ember that formed when cutting a piece of wood that had bound against the blade... No injury or harm other than setting off the smoke detectors and having a shopvac that smelled of smoke for a good year! Glad I didnt need more than a spray bottle to put it out!

As for the off topic conversation, I was refuting that the "thermite" was to blame for the fires. Its likely that a hot steel spark ignited something else. Thermite requires a very high temperature to ignite. Fine aluminum dust on the other hand goes off if you look at it funny... ;-)