What is that glowing red down there

**pjt** · 18th May 2011, 12:54 AM

I had a few tense moments today, I needed to reduce the thickness of a small shaped piece of ply, I was in the process of doing so and happened to glance down the gap between saw blade and table

WHAT IS GLOWING RED DOWN THERE plus a few other thoughts racing round the head, looked out the back and the DC is issuing forth with a steady stream of blue smoke

FAARRRRKKK. Turn saw off, pull hose off, yep, some little bits are smouldering nicely, drag the bits out, nothing actually alight tho, and no smoke, mmmmm, look out the back, still loads of blue smoke, more

, I have a 90° bend up into the DC with quick lock clamps on it, undid those as this is a place where bigger bits collect expecting this to be fully alight, nope but steady stream of blue smoke from the pipe, ahh it's on fire down there, I have a piece of conduit long enuff to shove down this piece of pipe, the thinking being I'll push the allight stuff along the pipe and onto the ground, which is basically what happened, but nothing really flaming, just smouldering, and not really that, a few little black bits that most likely did burn but with the airflow didn't burn with a steady flame, the scary thing is that I could have turned it all off and gone off and left the little bits smouldering and then it could have developed into something far worse

. I have been and checked a few times tonight, all quiet

On reflection there was a number of things that came together to cause this little incedent,
1- a collection of those narrow long bits that slip down between the blade and table into the hose, (I'll get that later)

this may have held up some bits of curly chips

2- a blade that's not blunt but usable but past it's best sharpness
3- having a build up of resin on the clearance portions of the teeth, from cutting resinous wood.
4-and the actual job... reducing the thickness of the piece of ply, maybe ripping along a glue line may have heated things up too much

the bandsaw would have been a better machine for this I think

Also on further reflection a number of things allowed me to resolve this drama without it turn into a real drama
1-being able to remove hoses from the machine without needing tools, I have in the past wondered whether I should have a hose clamp on some of these points, I think

2- having the quick connect clamps on at strategic points to gain access
3 having the pipework down low for easy access, this is out of neccessity more so than by design

A few conclusions
1- keep cutting tools sharp AND clean from resins, specially the high speed ones
2-open up all the gates from each machine to clear out any chips/dust that has settled in any pipework, dust seems to have a habit of collecting in pipework from a less used machine
3- hang about for a bit (especially at knockoff) after switching things off just to make sure nothings about to go up

Feel free to add any other thoughts.....

Pete

**BobL** · 18th May 2011, 01:04 AM

Very interesting - my first thoughts are.

You had a glowing embers in the DC and the DC or ducting did not explode

The thin bits that fall down between the blade and the throat plate are a PITA. One of the TS at work had a shallow bin into which these bits could fall and the take off ducting was off to the side. A small metal door allowed access to the cabinet interior to clear these thin bits. I have often thought about remaking my hopper underneath my TS to be like this.

Everything else you've written I agree with.

**orraloon** · 18th May 2011, 10:48 PM

Making me feel good about not getting around to extraction for the table saw yet.
I did nearly have a fire with the belt sander after grinding metal on it. Sparks went into the bag of wood dust.
Regards
John

**Avery** · 18th May 2011, 11:06 PM

wow!

that is a bit scary. I guess it is a problem having smouldering bits being sucked into the dusty. There must be a way to prevent this.

Like Orraloon , I have made the mistake of sanding metal on a woodworking tool, causing smoke and fire (could have been serious but it won't happen again).

**pjt** · 19th May 2011, 09:01 PM

It certainly was a bit scary, I had visions of the whole thing going up, Bob mentioned explosion, I didn't think it was going to explode, just burn, but it is one of those often discussed subjects....whether a DC/DC ducting will or can explode, it will certainly burn

, it could explode if the correct conditions are present, an explosive environment needs the correct air to fuel ratio and an ignition source, in the collection box would be the most likely place especially a little while after switching off as the dust is reaching the correct air fuel ratio and no air movement. This was my thinking for not turning the DC off until I had found all of the smoking bits, I was promoting a lean mixture.

Pete

**fletty** · 22nd May 2011, 10:03 PM

I know that horrible gut tightening feeling but mine happened when I had been cutting some steel, held in my bench vise, with an angle grinder, After cutting it, something made me look ander the benchtop. There, in the dark, was a ROLL of 0000 steel wool smouldering. I have never seen steel wool burn before but it was well alight when I dragged it out and took it ouside the shed. I didn't want to hose it but I unwound the outer burning layers and dropped them in a bucket of water. As Pete said .... what if!
fletty

**pjt** · 23rd May 2011, 10:33 PM

Originally Posted by fletty

I know that horrible gut tightening feeling but mine happened when I had been cutting some steel, held in my bench vise, with an angle grinder, After cutting it, something made me look ander the benchtop. There, in the dark, was a ROLL of 0000 steel wool smouldering. I have never seen steel wool burn before but it was well alight when I dragged it out and took it ouside the shed. I didn't want to hose it but I unwound the outer burning layers and dropped them in a bucket of water. As Pete said .... what if!
fletty

Iv'e been there as well with the burning steel wool, many years ago, (not even doing woodwork)

had a roll of it hanging on the wall, doing some grinding, I catch a orange glow from the corner of my sheild and look up and there it is fully alight

never would have believed that steel wool could burn

but there it was, grabbed a stick and hoiked it outside.

Pete

**ian** · 24th May 2011, 12:10 AM

Originally Posted by pjt

never would have believed that steel wool could burn

but there it was,

Pete
it's one way of starting a fire when it's windy. Strike some sparks flint into the steel wool and you're well on your away to pyromania

**fletty** · 24th May 2011, 12:50 PM

Originally Posted by ian

.........and you're well on your away to pyromania

OK, WHO is going to ask Ian how he knows?

fletty

**ian** · 24th May 2011, 07:24 PM

Originally Posted by fletty

Originally Posted by ian

... and you're well on your away to pyromania

OK, WHO is going to ask Ian how he knows?

fletty

it's the result of one too many exercises designed to demonstrate that "the team is more powerful than the individual"
in one scenario, your float plane has crashed in the wilds of Canada during a storm. Before the plane sank, you, the pilot and your fellow passengers managed to salvage the following items from the plane (insert apparently random list of 10 or 12 items, including a tin of lard, steel wool and a flint).
The "expert" solution, included using some of the steel wool and lard to polish the tin's lid to form a signalling mirror -- I don't recall if there was a tool for opening the tin!
and using the steel wool to catch sparks off the flint to start a fire.

Afterwards, I got some steel wool and gave fire starting a go -- it worked

**cookie48** · 25th May 2011, 05:42 PM

Food for thought in all comments. Am planning my pipe work now, but have now changed my mind about putting it along the roof line. Thankyou for bringing this to our attention.

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