CT 26 True CFM

[jaguar36]

I've been looking into getting a nice shop vac for a little while now, and was reading the comparison in Fine Woodworking.  They measured the CFM of the Festool CT 26 at around 70 CFM (dropping to around 40 when the filter gets clogged).  Thats a reading of about half went the rated CFM is, and significantly less than alot of the other comparable vacs.  Does anyone have any idea why this would be?  Measuring CFM is not complicated, so it seems very odd that they would get a number so far off from the advertised value.

 

[ajones]

I've been looking into getting a nice shop vac for a little while now, and was reading the comparison in Fine Woodworking.  They measured the CFM of the Festool CT 26 at around 70 CFM (dropping to around 40 when the filter gets clogged).  Thats a reading of about half went the rated CFM is, and significantly less than alot of the other comparable vacs.  Does anyone have any idea why this would be?  Measuring CFM is not complicated, so it seems very odd that they would get a number so far off from the advertised value.

Its because the idiots that did the test did not use a bag in the extractor and the test was not a true test as the extactors were not used in the manor they were designed for. and the whole article should be ignored.

[welcome] to the fog

 

[davee]

I have had teh CT26 since it came out and have been through many bags without seeing any drop off of air flow.  This includes sanding drywall.  As mentioned previously the FWW test allowed the filter in the vacuum to clog.

 

[Administrator_JSVN]

Welcome to the forum. There's a pretty lengthy discussion about that magazine comparison here that can shed some light on why the CFM was reported inaccurately:

http://festoolownersgroup.com/festool-tools-accessories/fww-vac-review/

As with all of our tools, you're covered by a 30-day no-hassle money back guarantee. Get it and try it. If it doesn't have the suction you expect, just take it back for a refund. No risk.

 

[jaguar36]

Thanks Shane, I searched around but didn't find that thread due to the lack of keyword friendly title.  Sadly that thread seemed to degenerate into people rather blindly defending the CT 26, as well as knocking the magazine for not testing it with a bag.

Regardless though, I'm still curious as to the true initial CFM.  Fine Woodworking measured an intial CFM of about half what Festool specs.  Adding a bag would only further drop the initial air flow rate.

 

[mikeneron]

Is there a tool or device out there to measure CFM?  Would be nice to see the actual CFM of my CT22 both standalone and then when I have it attached to one of those Vertias cyclone lids.  It definitely loses a bit of suction, but have always wondered how much.

 

[Administrator_JSVN]

The specifications for CFM on all five of our CT models is 137. That is the true initial CFM. Maybe there's a Festool dealer in your vicinity where you can see it in person and maybe even do a side-by-side comparison with any other vacuum(s) you're considering.

The testing methodology used in the FWW review basically allowed the HEPA filter to get clogged with fine particulate. The bag is designed to act as a primary filter and filters particles down to 5 microns in size. The HEPA filter will go down to 0.3 microns.

I believe that forum members reacted in the way that they did because the testing methods being used in the review were not following real-world use (with a bag) which is the way it CT was designed to be used. I would have liked to have seen the results with the bag in place in place of or in addition to the published testing results.

CFM Meters: https://www.google.com/search?q=cfm+meter&tbm=shop

 

[semenza]

Hi jaguar [smile]

Welcome to the FOG !  [smile]

In regards to the thread on the FWW test.......  I am not so sure about the blind CT defense. Many (most?) of the posters own Festool CT vacs. I think you will find that members of this forum will defend Festool tools when appropriate, and a little reading will find them also  pointing out the problems and faults  as well.  Which says something about the defense of the CTs.
It is also worth noting that one of the FWW  authors verified the bagless test,  and gave the reasoning behind the decision to not use a bag.  Regardless of the reasoning given for not using a bag, the fact remains that the Festool CT vacs are designed to be used with a bag, and the results of the test are certainly tainted by that decision.

I personally use   a CT22, CT33, and CT Mini. I have also used quite a few other shop vacs in various sizes and designs. There is no question that the Festool vacs have a much higher suction, and air flow, than the others I have used (and still have kicking around) and almost no degredation of the suction / air flow as the vac fills.  I have not used the CT26, but I have no reason to doubt its capabilities.

I think you will be happy if you give it a try, and as Shane pointed out. If you don't like it , you can return  within 30 days.

I do think you should consider a CT36 to better match your user name  [big grin]

Seth

 

[alik]

I think that FWW SHOULD DO ANOTHER TEST OF ALL VACUUMS WITH THE BAGS IN IT [mad]

 

[rdesigns]

AND they should do the tests with the same size hoses. My CT 26 with the 36mm hose sucks a lot more air than when it's connected to the 27mm hose, but the 27mm is less cumbersome and more than adequate for most tools, the Kapex being the most notable exception in my experience.

 

[jaguar36]

The specifications for CFM on all five of our CT models is 137. That is the true initial CFM.

I suppose the better question would be how is that CFM measured by Festool?  I would expect it to be measured at the end of the included hose (27mm) with a filter (and a bag if that is how the Vac is "designed to be used")  Or is Festool doing something shady like measuring the CFM without a hose, and without a filter or bag?

Keep in mind that I'm not asking if its a better vacuum, or how good it is as clearly there are a significant number of other factors to consider. 

 

[NoBreyner]

At this point you really should go to a dealer and check it out for yourself.  If there's any doubt about its capabilities you can always demo it at a store and see if you like it or not.

 

[peter halle]

The specifications for CFM on all five of our CT models is 137. That is the true initial CFM.

I suppose the better question would be how is that CFM measured by Festool?  I would expect it to be measured at the end of the included hose (27mm) with a filter (and a bag if that is how the Vac is "designed to be used")  Or is Festool doing something shady like measuring the CFM without a hose, and without a filter or bag?

Keep in mind that I'm not asking if its a better vacuum, or how good it is as clearly there are a significant number of other factors to consider. 

I certainly can not tell you how the CFM's are measured, but I can tell you that usually Festool's advertised specs are conservative rather than being inflated or hyped like other brands.  They have had the policy of allowing users to try out their products for themselves in their own real life situations and make an informed decision based on their usage.

Shady - as evidenced by the openness on this forum as well as the aforementioned - and Festool do not go together in the same sentence.

Peter

 

[Ken Nagrod]

Jaguar36,

Shop by numbers or shop by results.  You can spend all year playing with the numbers or just compare the vacs in actual use, the way you'd use them.

 

[ccarrolladams]

Dust collection is a complicated issue. Different machines need different dust collection approaches.

When people who are not experienced in measuring air movement attempt to evaluate and then compare totally different machines, for most of us the resulting opinions are useless.

Typical permanent shop dust collection is based on very large volume of suction at fairly low velocity. Going back generations with pioneer duct systems not well sealed and existing blowers, low velocity and high volume made up for leaks and worked well enough. As a result even with better blowers and duct sealing typical shop dust collection is high volume and low velocity. Most portable shop vacs are also high volume/low velocity.

Festool took a different approach which they term "Dust Extraction"  To make hand operated tools practical the extraction hose needs to be both flexible and much smaller than typical 4" or larger dust collection hoses used on fixed machines. Since only so much volume can be moved through a 27mm hose, Festool wisely designed extraction machines able to pull air at high velocity.

Sanders used with dust extraction need methods of exactly regulating the suction. For this reason the Festool CT extractors have a continuously variable volume adjustment. Some other Festools benefit from adjustable volume of suction while other Festools work fine with full extraction.

What does not work effectively is to replace a Festool CT extractor with a non-variable low velocity dust collector. Simply increasing the volume does not compensate for the low velocity. When collecting dust from a hand operated sander very little volume is needed and more does not help. In fact, it might make the sander less effective.

Festool has a history of being responsible about the air quality in woodworking environments. Sure, really good collection bags reduce volume of suction. Same is true of approved HEPA filters small enough to be portable. Bottom line is that since mid 2011 all of the Festool CT extractors have used blowers of identical capacity. The bags and HEPA filters do vary with CT model. Bottom line is all of the Festool CT extractors have the appropriate ratio of volume and velocity to be effective with all Festools assuming the correct hose is used.

In my opinion it would be better if Festool offered a 36mm AS hose of just over 2m in length for best results with the Kapex. Meanwhile they sell the 36mm x 7mAS hose, as well as extra connectors. From that hose I make the shorter ones for 3 Kapex.

Used with a 36mm x 7m hose all the Festool CT have enough capacity to use tradesmen cleaning tools. Perhaps a typical shop vac would move more air, but then it would not be releasing HEPA filtered exhaust. In my opinion returning dirty air into the shop environment is not just silly, it is counter productive.

On a construction site before all the openings have been sealed returning dirty air might not be a major problem. However, when the space is sealed property owners become more fastidious. This is when finish carpenters and cabinet makers are more closely supervised. Personally I have never been asked to install cabinets on a job site that was unsealed.

Also I am in the business of using and making money with my Festools. I am not in the business of doing endless literature research authored by people of unknown qualification and conflict of interest. If I need to know if a product will be appropriate for my use, I arrange to personally do the tests.

I recommend Festool extractors for use with Festools. Personally I selected the CT22 because I did not want to lift a heavier larger bag, just to save some on bag cost, which I factor into every bid. I have found my Festool CT22s also work great as my personal household vac at home, because thet do not interfere with the TV and with the volume turned down they are quiet.

I do not recommend Festool extractors for use with fixed machines. To me those need larger dust collection systems. My shop is in a jurisdiction where normal portable DC machines are not approved for indoor use. I was required to install an outside DC system, although I am allowed to use as many Festool CTs inside as I desire. 

 

[jaguar36]

If all of the vacuums have the same CFM rating, that would imply that it is not a spec based on the complete system but rather based on something like the blower sitting on a bench without the rest of the vacuum, and would therefore indeed be a rather meaningless number.  Particularly considering that the mini/midi have the same CFM rating as the bigger vacs, while only have a 1-micron filter.

That would seem to be why FWW got such a lower flow number than the spec, as adding a filter and a hose into the mix could easily drop the flow rate by half.

Its great that most Festool dealers will let you go and try out the tools, and a money back guarantee is also great.  I certainly wouldn't have bought my Domino without having tried it out first.  Keep in mind however, that going and trying (or buying and returning) a tool is a significant investment, particularly if there is no dealer nearby.  It will never be practical to try out all the various models in the market, and therefore "shopping by the numbers" is at least required to at least narrow it down to a few models to try.

 

[tbellemare]

the mini/midi have the same CFM rating as the bigger vacs, while only have a 1-micron filter

The newer version of the MINI and MIDI that have the same powerplant as the CT 26/36/48 also have HEPA filters.

Tom

 

[ajones]

If all of the vacuums have the same CFM rating, that would imply that it is not a spec based on the complete system but rather based on something like the blower sitting on a bench without the rest of the vacuum, and would therefore indeed be a rather meaningless number.   Particularly considering that the mini/midi have the same CFM rating as the bigger vacs, while only have a 1-micron filter.

That would seem to be why FWW got such a lower flow number than the spec, as adding a filter and a hose into the mix could easily drop the flow rate by half.

Its great that most Festool dealers will let you go and try out the tools, and a money back guarantee is also great.  I certainly wouldn't have bought my Domino without having tried it out first.  Keep in mind however, that going and trying (or buying and returning) a tool is a significant investment, particularly if there is no dealer nearby.   It will never be practical to try out all the various models in the market, and therefore "shopping by the numbers" is at least required to at least narrow it down to a few models to try.

So Jag what extractor do you use with your domino?

 

[Administrator_JSVN]

I don't know the methods used by Festool Germany to determine the CFM rating for the CTs. I'm pretty sure there is no industry standard for the testing method. The same is true with torque ratings for drills. And the list can go on.

It's left up to the manufacturer to determine the method for testing. I don't know that there's any requirement for any manufacturer to provide substantive proof that the numbers listed are accurate or can be reproduced under real world conditions. So, you'll never be comparing apples to apples just looking at the numbers. As others have stated, Festool is very conservative with its specifications, much more so than other manufacturers.

I'm not sure you're going to get a satisfactory answer to your question. I would suggest you base your decision on hands-on demonstrations, the feedback and opinions of actual owners, and the reputation of the company. Thank you for considering our dust extractors.

Shane

 

[AlexThePalex]

the mini/midi have the same CFM rating as the bigger vacs, while only have a 1-micron filter

The newer version of the MINI and MIDI that have the same powerplant as the CT 26/36/48 also have HEPA filters.

Tom

While the actual CFM ratings are measured in Europe with the standard filters and not the USA specific HEPA filters.