CT33 fire

What did you do, sweep up a burning cig?

I almost did when I was sanding down something with square cut nails in it.
 
I was routing a table top edge in rift white oak. 1400 router with 1/2 straight bit cutting 52 inch diameter table ,taking about 5/16" per plunge.
 
Wow, that will really ruin your day.  [scared] There are only two things I could think of that could cause this. The most obvious is the ingestion of a hot metallic ember. The second is a fermentation or chemical reaction from something already sitting in the bag (kind of like how finishing rags can spontaneously combust). Is there anything unusual that you vacuumed up in the recent past?
 
Wow!!! I have never seen anything like that.

I am curious to know what caused that.

Dan Clermont
 
Were there any bluish stains in the oak that you were routing?

Peter
 
No stains in the oak , The contents of the bag was chips and dust, as I spread out the contents of the bag to check for burning embers.
 
Fortrout, from the pictures it looks the fire was completely contained in the dust compartment, as far as you know the motor had noting to do with the fire, is that correct?
 
I would suggest that you search what you were cutting for a piece of metal that may have caused a something to spark and get ingested and then...  You have evidently used you CT for at least one project.  It wasn't the CT.  I asked about blue - that would indicate iron (nail, spike, etc while the tree was growing)

Maybe something after it was harvested.

Peter
 
"A little bit off subject. The other day I was routing out Russian Birch plywood 3/4 inch using 1/2 inch bit, 1400 with CT22 and MFS. I was creating a round mirror frame  with a 30 inch interior groove to receive the mirror. I was taking off 3 mm of material at each pass so not to overheat the bit. I was finishing the second pass when I notice the saw dust left in the groove was smoking in one spot. I lifted with my glove hand the dust and there was a 2-3 mm piece of  material burning like hot coals.

I was wondering if anybody had this experience before, would it have started a fire in the CT22 bag and what is a spark arrestor for vaccum."

Bruce

I posted this incident on a different thread. This may what have happen to you with the hot coals ending up in your bag. I may need to look into an spark arrestor when using larger bits with my router.

Bruce
 
I was taking off 3 mm of material at each pass so not to overheat the bit.
Click to expand...

I may be mistaken but I don't think so...

Trying to do too little with any cutter - whether it be a drill bit, a router bit, or a saw blade, is going to heat it up much more than trying to do too much.

The cutter is made to cut. If it isn't dull and the proper speed and feed are applied, it will cut. The act of cutting is going to cause it to be self cooling (to a degree). Obviously, if one is cutting metal, the story changes SOMEWHAT. Cutting fluids are only partially used for cooling.

The point I'm trying to make is that the cutter is going to overheat if it isn't taking out the proper amount of wood with each pass. That proper shaving is actually going to ride against the cutter on the way out of the cutter's way and "remove heat" by virtue of the contact it made with the cutter and the fact that it has heat transfer and storage capabilities independent of the cutter.

If the cutter is allowed to "dwell" in the material, it isn't cutting, though it has frictional interaction with the material and heat buildup occurs. That same heat buildup can cause the work piece to burn and the cutter to get REAL hot, thus causing both to be ruined.

My father taught me these principles when I was too young and weak to use his drill to drill a hole in the bumper of a '62 Galaxy. When I pushed on the drill, it made no hole and started to get really hot. When he pushed on the drill, it CUT shavings that looked like a pig's tail. 'Lesson learned...

I continue my "Thanksgiving"... Thanks, Dad!

Tom
 
It would appear that the filters and the filter mounting area took most of the damage. Back to the original question, no one else has had a fire in their vac?
 
Any chance you had sanded something with finish on it (oil based) sometime in the past? Then fed O2 to it when you used it this time.
Looks like it likely was spontaneous combustion. The bag had a lot of mixed goodies in it..
Good thing that it was contained in the unit. See this with flooring re finishers and the sanders.
 
I had not vacuumed any oil finish, I only hook this machine up to my other Festools. I have a old Sears shop vac I use on floors. The Sears vac is currently hooked up to my Kapex.
 
hi fortrout, with regards to your original question.

i have never had either of my festool vacs go up in smoke like this.
i use the ct 22 and ct 33 joinery work in my garage. i use a long life filter bag on both when sucking up wood dust/chips.
i use a festool disposable paper bag when sucking up epoxy resins/filler or old paint.

i do not take them on site to suck up concrete dust.

i know a few tradesmen with festool vacs, but i have never heard of this issue before now.
i hope you can salvage the vac.

regards, justin.

 
Out of interest how full was the bag? just wondering with regard to heat and compression. I often sand floor varnish etc but never let the bag become completely full.

Not sure if the spark chamber would help or not. I have seen them in the catalogue

http://www.festool.co.uk/images/gb_downloads/1011_catalogue/13_dust_extraction.pdf

under CT accessories (part # 484733) but there is no literature explaining how they work. I believe that they retail at about ?90.

 
The bag was either half full or half empty, depending on your level of pessimism. This is the first i have heard of a spark chamber,thanks
 
Thanks for posting, Fortrout.
It appears in pict. #2 that there were 2 holes burned through the intake just inside the unit before the dustbag?
This might be a case for Mulder and Scully...
 
Gents:

The Spark Trap is a metal (I believe steel) device that you put immediately in front of your CT. It is a cylindrical chamber with a vertical baffle that knocks flying objects out of the air stream and sends them to the bottom of the steel donut before they have a chance to fly into your bag.

The ostensible purpose for this "Spark Trap" is to trap sparks if you are cutting metal. It is also useful if you are cutting or vacuuming things that are big chunks that can hurt the bag. They get knocked down on their way in and you can collect them from the bottom of the Spark Trap at the end of the session.  'Think, chunks of tile, or concrete, or anything massive and sharp. The CT's can pick up some pretty big stuff...

Tom
 
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