Difference between L and M class dust extractors

[ToolCrazy]

Is there any physical difference between a CTL 26 and CTM 26 dust extractors filtration capability, other than the additional low suction warning on the M series dust extractors? Despite the M dust class having a "finer" dust filtration rating than L class, I see no physical difference in the filtration.

Both L and M class use the same filter bags - "SELFCLEAN filter bag SC FIS-CT 26/5", Item number 496187.

But there are some odd differences listed for the flat cartridge filters on the different models on the Festool product site:
- CTL 26 E & CTM 26 E use Main Filter HF-CT 26/36/48, Item Number 496170 (yellow in photo).
- CTL 26 E AC & CTM 26 E AC use Main Filter HF-CT 26/36/48 HP, Item Number 203759 (white in photo).

I would have expected the L models to use the same cartridge filter, and the M models to use a different cartridge filter, but that is not the case as per the paragraph above.

Are filters 496170 and 203759 the same or different? Other than the colour?

It seems that L and M models actually have the identical bag and filter, and therefore filtration capability.

 

[mino]

No. The only difference is the flow sensor.
CTM 36 AC owner.

There are a couple different filters around.

But they are not related to the M/L class divide (for Festool). Even the "weakest" filter available meets the M Class filtration requirements.

In Europe, there is the "normal" paper filter and the AC plastic Hight Performance filter. In other markets there are some additional "HEPA" certified filters but I have never really seen a proper comparison between all.

If you want best filtration with cost-no-object, one can also use the H-Class main filter and H-Class bags even in a CTL26. The H-class filter and bags better at the micro-particle thing. But that is kinda pointless for wood as such small particles are not produced even from sanding. Is mainly for Asbestos and car paints etc.

ADD:
The high performance filter can be used with AutoClean. The paper one cannot. If you buy an AC vac, it is best to still buy the paper filter for non-AC usage as there is no advantage to the HP filter when AC is not used.

Also, once a filter is used without bags, it should never be used with bags again. So the provided AC filter is best to reserve for AC use bagless and get a paper normal filter for non-AC use with bags.

Note:
Do never use AC /even manually triggered/ with bags. It would damage the SelfClean bags and they will leak more as a result.

ADD2:
Festool never produced "lower than M class filtration level" vacs. Even before the L/M/H classification was created. They never had bags that would meet L but not meet M.

So for them the only difference is that the vac models without sensors cannot be certified as M class, hence they are, legally, "L class".

The same is the case with CT15. It does not have a "class"  specified as it is not certified. But it provides the same filtration as the CTM Midi, using the same filter and same bags.

Legal and reality not always meet.
8)

 

[ToolCrazy]

Thank you Mino for the very comprehensive reply – much appreciated.

This confirms that a CTL is sufficient for my limited workshop purposes as I am not a mobile contractor. I have some questions about your reply on the AC function.

I cannot think of a scenario where I’d use the dust extractor without a bag. If anything, I may sometimes connect a small cyclonic separator before the dust extractor, like for a large routing job, if I’m expecting that there will be a large volume of wood shavings, to make waste disposal easier and to make the bag last longer. For jobs like sanding, I’ll just use the dust extractor without the preceding cyclonic separator.

• Why would the dust extractor be used bagless?
• Can you explain your statement: “Do never use AC even manually triggered with bags. It would damage the SelfClean bags and they will leak more as a result.”

Thanks

 

[mino]

AC is for plaster/drywall and, in general, for mineral materials sanding.

Those produce huge quantities of microparticles which clog a bag pretty fast so a reverse-flow filter cleaning is a must.

AC is not for wood though as the light wood fibres would clog the microfilter and the reverse flow from AC would not dislodge them.

AC => Bagless + HP filter, cyclone optional
non-AC => Bag + any filter, cyclone optional

 

[ToolCrazy]

Wow! That totally changes my thoughts on what the most appropriate dust extractor model is for (a) home woodwork and (b) general workshop cleanup. I was thinking the following:

• Size: 26 (sufficient for my home workshop - I'm not a contractor and I don't need cordless)
• Dust Class: L (although I may occasionally sand carbon fibre layups, but will use a respirator and/or do this outside
• AutoClean: Yes (now I'm thinking No since I will never work on drywalling)
• Bluetooth module: Yes (since I have some non-Festool tools that will not plug into the dust extractor [incompatible plug], and I'd like to start the dust extractor remotely. I also do not need the air tool module, second plug socket or energy box module.

Thanks again for your advice Mino. Would you agree with the above for my purposes?

 

[mino]

If you are not sure, just get the AC model. The price difference is not that much and when you need it, you have it ...

And stop thinking in L-Class sense. L-Class standard is total junk for anything but home/general use.

The Festool vacs certified for "L Class" are not good because of that but because they have high quality filters and mostly the bags are one of the best on the market.

I am not sure of the precise data, but the CTL26/36 as well as the Mini/Mid/CT15 series exceed the formal "M Class" standard filration requirements by a sizeable margin.

We have a couple new Makita and Nilfisk "can-style" L-Class in the shop, and there is just no comparison. We quickly learned to put a couple pieces of cloths over the bags as they leak like crazy and mess up the main filters ... on my CT 36 the main filter has barely any dust on it after a year. And the bag does not leak even when used with a cyclone so only smallest stuff getting into it.

 

[Coen]

AC => Bagless + HP filter, cyclone optional

You can still use the 'open top' plastic liners / totes, whatever is the correct translation.

Do never use AC /even manually triggered/ with bags. It would damage the SelfClean bags and they will leak more as a result.

Interesting as Bosch rep said he always uses a bag in his GAS 35 M AFC.=500

I know one thing... using the CTL 26 with original filter and the SelfClean bags in combination with the wall chaser in concrete... it will reduce suction long before the bag is full.

But I still wonder about the AC vacs... Fine dust... even if reversed and it's blown out of the filter... doesn't just 99% fly straight back into the filter?

 

[guybo]

 

[mino]

...
But I still wonder about the AC vacs... Fine dust... even if reversed and it's blown out of the filter... doesn't just 99% fly straight back into the filter?

Fine wood dust which is very light does. In addition to sticking the fibers in the filter.

Mineral dust is heavier so /mostly/ does not - the air flow is not sufficient to overcome the gravity.

As for the bags versus AC:
Firstly the SelfClean HIGH QUALITY bag will clog as it is not designed for that type of dust.
Secondly, the violent trashing will damage the bag at places, making it leak microparticles which will thus get to the main filter in significant quantities.
Since there the cleaning is most violent at the main filter, the finest dust will accumulate all over the chamber, BETWEEN the bag and the main filter. Making the /high quality and expensive/ bags mostly pointless as they will NOT improve filtration quality /defined by the main filter/ nor air flow by creating additional resistance.

Now, if you have a vacuum using crapy bags, WHICH LEAK ANYWAY AND DO NOT CLOG as they simply do not catch micro-dust, then this can indeed optically "work better" than bagless as long as you accept the need to cleanup the vac all around as if you did not have a bag there.
But practically it will still be worse if you measured the micrtoparticle quantiies and took into account the lowered airflow thus worse capture at source.

But the reason to not AC with bag is other. I meant it that when use with bags, one should not use AC /even manually/ to "shake up the bag a bit" as this is VERY violent for the bag and damages it. It is also completely pointless with the SelfClean bags. Do not ask how I know ...

 

[bidn]

Re. the different classes (size of dust particles) for a given vac:
I was told by dealers and saw on German forums the following:
These vacs are identically built with the same identical components in the same manner.
The issue is that laws in some countries require that professionals use vaccuum units which have been
tested and certified as compliant with some level of dust filtration. The certification process makes the units more expensive but the companies (usually bigger ones) have no choice than to buy such more expensive units for their employees.

If one has no such legal certification requirement, one can better save money by going for a cheaper, not certified unit.

 

[Coen]

It's just the flow sensor costs money, and regardless of everything else... you don't get M class without it.