Author Topic: CTM Midi Dust Extractor  (Read 5772 times)

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Offline Bossman

  • Posts: 1
CTM Midi Dust Extractor
« on: November 24, 2018, 12:59 PM »
I have just been shown the new CTM midi which looks pretty impressive but the one thing that will stop me buying one is the introduction of two blow holes (one each side of the extractor), which you can attach the existing hose to and use to blow air. The downside with this is that when using as a conventional hoover, the blow holes moves the dust into the air. There is a vented door covering the holes which in my mind should have had some form of sponge defuser/filter but then that is only my opinion.
Sorry Festool I'm not buying this one.

 

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Offline Alex

  • Posts: 6082
Re: CTM Midi Dust Extractor
« Reply #1 on: November 24, 2018, 03:11 PM »
Completely unnecessary feature, those blow holes, I need a  vac to suck, not blow. Anyway, if I need to upgrade at one poin I'm not gonna let some holes get in my way, I'd just plug them, but I shouldn't have to. I agree with the idea that such blow holes introduce more particles back in to the air.

Offline Frank-Jan

  • Posts: 1044
  • Dutch Canadian living in Belgium
Re: CTM Midi Dust Extractor
« Reply #2 on: November 24, 2018, 06:09 PM »
The older festool vacs (ct22, 33 etc) also had such a feature, but in normal operation NO air would come out. (The cover acts as a one-way-valve)

If there IS coming air out of those "blowholes" when there is no hose attached, I assume it's just exhaust air, which is filtered, instead of a bypass like on the older models.



Offline Laminator

  • Posts: 343
Re: CTM Midi Dust Extractor
« Reply #3 on: November 26, 2018, 08:46 AM »
Years ago I used the blow outlet on my ct22.  Instantly learned that any dust trapped in the hose will spew out into the air so I abandoned the idea of using the vac to blow.

Offline Spandex

  • Posts: 13
Re: CTM Midi Dust Extractor
« Reply #4 on: November 26, 2018, 06:18 PM »
Surely all extractors have to blow air out (otherwise where would it go?  [wink]). So why is there going to be more dust in the exhaust air on the new design than there was in the old one?

Offline Gregor

  • Posts: 1301
Re: CTM Midi Dust Extractor
« Reply #5 on: December 03, 2018, 08:45 AM »
Years ago I used the blow outlet on my ct22.  Instantly learned that any dust trapped in the hose will spew out into the air so I abandoned the idea of using the vac to blow.
Simple solution to this problem is to shortcut the vac with the hose (connect it to both input and output) for a moment in which you shake/knock/beat the hose to dislodge the dust cakes that have built inside it. This takes care of any dust that might get blown free, after that you simply pull the hose from the inlet to use it as a blower (without causing visibility problems).

So why is there going to be more dust in the exhaust air on the new design than there was in the old one?
The problem (for vacs with a HEPA filter) isn't in the exhaust air, but the way it's emitted. Having an outlet eject a concentrated stream of air is likely to raise dust from the surfaces where it's directed at - hence you want a vacuum design where the outlet is big and diffused to cause as less wind as possible, so you can suck up dust from where it's sitting (instead of turning it airborne and float around the room for the next hours).

Offline Spandex

  • Posts: 13
Re: CTM Midi Dust Extractor
« Reply #6 on: December 03, 2018, 03:14 PM »
That’s not the issue the OP claimed existed.

That being said, I’m not sure it’s that big a deal anyway. The CT can be 3m away, pointing in any direction you choose.

Offline Harold999

  • Posts: 4
Re: CTM Midi Dust Extractor
« Reply #7 on: February 08, 2019, 12:17 AM »
Air coming out of the blow port is filtered by the main filters. It's not the bypass stream which cools the motor but the main stream you've sucked up through the hose.
As a matter of fact i think it's neat to have the ability to attach a second hose permanently to the blow port and lead this hose out of a window. Especially when sanding lead-paint or other VERY fine (quartz) dust which can pass the filters in small amounts.
You can dump it outside now.

Offline Alex

  • Posts: 6082
Re: CTM Midi Dust Extractor
« Reply #8 on: February 08, 2019, 03:46 AM »
As a matter of fact i think it's neat to have the ability to attach a second hose permanently to the blow port and lead this hose out of a window. Especially when sanding lead-paint or other VERY fine (quartz) dust which can pass the filters in small amounts.
You can dump it outside now.

You miss thousands of times more dust at the point of origin, which does not get sucked up in the vac, than those few particles the filter lets slip through.

Offline Harold999

  • Posts: 4
Re: CTM Midi Dust Extractor
« Reply #9 on: February 08, 2019, 09:09 AM »
As a matter of fact i think it's neat to have the ability to attach a second hose permanently to the blow port and lead this hose out of a window. Especially when sanding lead-paint or other VERY fine (quartz) dust which can pass the filters in small amounts.
You can dump it outside now.

You miss thousands of times more dust at the point of origin, which does not get sucked up in the vac, than those few particles the filter lets slip through.

Once you sucked up lead pigments or other ultra fine dangerous dust, the filters and bag are contaminated for their total lifespawn. Next time you use the vacuum it's still blowing out lead pigments and the weeks after that.
In case you use the vac as a fixed shopvac it's not a bad idea to lead the blowed out air outside the window all the time.
« Last Edit: February 08, 2019, 09:17 AM by Harold999 »

Offline Alex

  • Posts: 6082
Re: CTM Midi Dust Extractor
« Reply #10 on: February 08, 2019, 09:41 AM »
As a matter of fact i think it's neat to have the ability to attach a second hose permanently to the blow port and lead this hose out of a window. Especially when sanding lead-paint or other VERY fine (quartz) dust which can pass the filters in small amounts.
You can dump it outside now.

You miss thousands of times more dust at the point of origin, which does not get sucked up in the vac, than those few particles the filter lets slip through.

Once you sucked up lead pigments or other ultra fine dangerous dust, the filters and bag are contaminated for their total lifespawn. Next time you use the vacuum it's still blowing out lead pigments and the weeks after that.
In case you use the vac as a fixed shopvac it's not a bad idea to lead the blowed out air outside the window all the time.

This comment is totally unrelated to your previous comment about the extra hose, and my answer to it, what's your point?

I don't see why it is important to worry about the finest filtering in your vac and then ignore the huge amount of dust that doesn't get sucked up at the source, the sander itself.

Besides that, lead poisoning is about criticial concentration. The minute amount that escapes the filter is not going to be a health hazzard, especially not to adults, unless you work with huge amounts on a daily basis, in which case I strongly suggest you look at more specialised gear with H-class filtering instead of M-class. And in case you didn't know, lead poisoning is most influential in children because it interrupts processes during their growth. Adults are far less in danger, so working with lead paint occasionally should not worry anybody. But keep your kids away from your work area.

If you're worried about lead during sanding, don't focus in vain on your vac's filters, but go for real protection and use a respirator. I very often use one during sanding.

Offline Harold999

  • Posts: 4
Re: CTM Midi Dust Extractor
« Reply #11 on: February 08, 2019, 01:11 PM »
As a matter of fact i think it's neat to have the ability to attach a second hose permanently to the blow port and lead this hose out of a window. Especially when sanding lead-paint or other VERY fine (quartz) dust which can pass the filters in small amounts.
You can dump it outside now.

You miss thousands of times more dust at the point of origin, which does not get sucked up in the vac, than those few particles the filter lets slip through.

Once you sucked up lead pigments or other ultra fine dangerous dust, the filters and bag are contaminated for their total lifespawn. Next time you use the vacuum it's still blowing out lead pigments and the weeks after that.
In case you use the vac as a fixed shopvac it's not a bad idea to lead the blowed out air outside the window all the time.

This comment is totally unrelated to your previous comment about the extra hose, and my answer to it, what's your point?

English is not my native language so maybe you've understand me wrong, but my -totally related- point was that having an extra hose permanently connected to the blow port, and lead this outside the house, can make sense. Even if it's very little, the air you're working in is cleaner.
Sure you can buy an H-class vac if you are worried about the smallest particles, but these are in a totally different price range.