Festool CT 25 Particle counts - doesn't appear to be filtering

[mino]

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- A HEPA filter is only as good as it's seal. The bosh unit has a gasket built into the filter, so that gets replaced each time a filter is changed. I believe this is how it works on the ct 26. The gasket was not a part of the CT 25 filter, so I could see the seal on these units degrading over time.
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I have a 2011 Protool VCP 480-L (a.k.a. one of the early models of the Festool CT 48 AC HD).

It was a vac that I got from a tool rentals as it had the top plastics broken, not worth of them repairing anymore.

Everything on the vac, excepting the motor which was very likely replaced a couple times given the high usage it got subjected to is .. original from 2011. Including the control electronics.

Long story short, the seal on the tub is as new /that is after 10+ years of heavy abuse by cheapo tradespeople who would not afford their own vac/.


Do not assume that just because junk 'seals' found on shop vacs and and other cheapo kit fall apart after a year or two, the Festool ones do as well. The same goes for their plastics, those are made to last 20+ years.

Tech-wise, from the 1980s on, it is a choice to make stuff from disintegrating plastics and degrading seals, a choice FT does not make as a matter of a policy given all their tools are sold with 20+ year lifespans presumed. Many users on here carrying on 40+ year tools from them.

Secondly, the only* seal you care about for HEPA and co is the one which is part of the main filter ... and that one you replace each time you replace the main filter. Not that the one would not last in elastic state for 10+ years. It does. Everything before that seal is in a vacuum zone and everything behind that seal is already after the filtration was done.

*) Yeah, with vacs that have AutoClean - creating overpressure pushes inside the tub - you do care about the tub seal as well, an order of magnitude less, but you do. See comment above for that one.

 

[Cheese]

This may be more towards those new to Festool, but one aspect of the Festool extractors that doesn't seem to get mentioned much anymore in the HEPA world is that the units themselves are HEPA rated - meaning that all the suction air that comes thru the unit is filtered and the unit itself is made so that it seals to prevent unfiltered suction air from exiting. Jut because you toss in a HEPA filter into a shop vac does not mean that all the suction air coming out will be HEPA filtered due to potential leaks in the units. If you truly want HEPA then you need to locate a HEPA unit - not just a HEPA filter.

Peter

I read an article somewhere on all of the details that Festool had to address to ensure their vacs are HEPA rated for the long term. The long list of seemingly small, insignificant items was stunning, certainly more than I was aware of and certainly more involved than just stuffing a HEPA filter in a vac.

 

[ReneS]

Re the air testing tool...

Seems to me you can test it's reliability even if you cannot test its validity, meaning the accuracy of the number that it produces.

Once you ensure that it produces the same number for the same or very similar condition, then at least you can compare different vacuums and extractors to each other.

So while you may not know the actual particulate count, you can know whether one machine emits more particulate, then the other.

 

[mino]

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So while you may not know the actual particulate count, you can know whether one machine emits more particulate, then the other.

Hate to burst your bubble, but this is false.

The core issue here is you do not know what the tool is actually measuring at any given point. In short, the only thing such a blunt measuring tool is useful for*) is time-comparative assessment of the same thing - the same vac over time sucking the same material in the same way in the same environment /impossible to guarantee, fail#1/ at different points in time. Things like looking for unexpected changes to known-behaviour systems, think indications of suddenly broken seals etc. Even there it is very tentative.

This type of a super-simple "particle meter" is, by its design, bunching together all kinds of particles and with unknown accuracy between them, to make it more fun. From the smallest to the big ones that would settle fast, from the harmless carbon dust from the brushes to the carcinogenic lead paint dust, etc. This means that the only thing scenario in which it can reasonably well measure something comparatively is if your dust environment has a static contaminants composition AND the air is not moving /much/ as any air movement will skew the results due to the way the internal laser uses timing for assessment.

Want to check if your neighbour burning garden garbage is affecting your air compared to the day before when he was not doing that - probably good-enough. Anything else more specific is a GIGO. Garbage /data/ in, Garbage /conclusions/ out.

ADD:
*) In the context of misusing it for assessing things it was never meant/designed to do, like the efficiency of specific devices, not mention their comparison. It is a good device for what it is meant for -a blunt assessment when you live near a dust source like a road and want to know when to ventilate the house. Or when your shop air is "dusty" - so can do something with it. Not for assessing how/why/how much it got so.