Festool Domino and CT26 First Thoughts

[RFGuy]

Thanks Ed. I REALLY appreciate all of your help. I did reach out to Festool today, but their technical people are out for the holidays so it might be slow to get a response. They did offer me to return it where I purchased it from if I want. Within first 30 days you are supposed to be able to do that no questions asked. Problem is I bought it online, so I really hate having to go through that whole process for a return....if there is a fix that can be done.

I have tried to be methodical and try a few experiments and carefully inspect in/around the filters and bags. Honestly, I really don't know what to make of any of it. One experiment: I thought perhaps that I had let the corner of the bag lay over the seal of the vacuum (between top and bottom halves - causing a gap maybe). So, I tried testing with and without, but couldn't discern a difference. It is strange because if you look at the rectangular HEPA cartridge it is pretty clean in the pics below. The filter bag has some fine dust on it, similar to yours. Overall, your filters look much cleaner, but that is to be expected since you have the cyclone in front.

Either there is some kind of leak, and not an obvious one, that is causing what I am seeing. Or, my expectations of Festool CT26 performance are out of line with the supposed filter specifications of this vacuum. All I have is the A-B comparison of it versus my ShopVac™. I wish I could get some cold hard data to reasonably compare them, because I am just relying on my observations at this point and my assumptions could be flawed. Perhaps, this vacuum just can't be run without a cyclone in front of it to get reasonably acceptable performance. I did order some punk sticks. My thought is to try to keep them far away from the vacuum and attempt to vacuum their smoke at the hose end to see if I can see any visible smoke exit the vacuum at the same time, such as from a bad seal or something. I am not sure if this will work and even if it does, it may mean nothing because I am sure smoke particles are way smaller than the minimum capture of the HEPA cartridge filter. Using a light and a magnifier, I have found very small amounts of dust on the black gasket that seals the top and bottom of the vacuum. Also, I noticed that when I engage the clamps on each side to seal the vacuum, that one side appears to take like half the pressure to close as the other one. I am wondering if perhaps the black seal is maybe too thin, at least on one side and it is causing leakage. This would certainly explain how the dust is bypassing the HEPA cartridge. I did do a paper test under the HEPA cartridge. With the filter clamped in place, I could not get a thin strip of paper to slide anywhere around the seal edge of the HEPA cartridge. Given this and the pics from inside the vacuum, I really don't think the HEPA cartridge is to blame.

If you have any other ideas for how to test, please share. I am kind of at a loss here. I hate to return the vacuum, especially if it is "good" and just doesn't perform as well as the ShopVac™. I mean if I return it and the 2nd unit is just the same, then it will mean that my expectations are unreasonable for it...even though the ShopVac™ outperforms it.

IMG_4477.jpg (82.1 KiB) Viewed 13942 times

IMG_4478.jpg (105.56 KiB) Viewed 13942 times

IMG_4479.jpg (96.13 KiB) Viewed 13942 times

IMG_4480.jpg (84.47 KiB) Viewed 13942 times

IMG_4481.jpg (74.31 KiB) Viewed 13942 times

[RFGuy]

Ed,

Please don't waste any more time on this, but I appreciate all of your help for my investigations. What I know at this time is:

1. The very first few Domino mortises that I did produced a significant amount of dust to spike my Dylos laser particle monitor. I mean like on the order of 500-1000 @ 0.5um scale per mortise. Since then I have not had anything come close to that kind of level again. Not sure why this is. Did the HEPA cartridge need a small amount of "cake" to fill in the pores to reach filter spec levels? Not supposed to be the case with HEPA cartridge filters, but ....

2. I made a poor assumption and had the ShopVac™ too far from the Dylos relative to the CT26. My shop is small, but that is no excuse. After moving a good bit around to get both the CT26 and the ShopVac™ side by side, I seem to be getting different results now. With a nearly clean room level shop (ha ), I tested the CT26 and the ShopVac™ independently (resetting the room in between). I get "near" same results with each now. For an identical, small amount of dust (from miter saw) including fine sawdust, I get about a 50 count rise with the ShopVac™ and perhaps 70-80 with the CT26. The ShopVac is broken in and has a good amount of "cake" built up in the HEPA bag and perhaps the HEPA cartridge, so I am going to call these near identical at this point. Both raise ambient dust particle counts.

3. Related to number 2 above, if I do a single mortise I get about 200 count rise with the ShopVac™ or the CT26 with the CT26 on the higher end and the ShopVac™ on the lower end of this estimate.

4. All dust count numbers are wild a** swags here. The meter has a running average display and I don't know how deep the buffer is. It does update fairly quickly so the buffer has to be small. I do have the upgraded model that datalogs to a PC, but I was just too lazy to drag a laptop out to the garage to datalog. This would have been the more accurate way to not only capture the dust counts, but to know how they are changing in time. Then I would have had to integrate under the curve for each of the tests and I am just too lazy to do that right now, especially with everything going on with the holidays.

INTERPRETATION: So, what does it all mean? I do think I have been chasing my tail here. I can't reproduce the original alarming finding in item #1 above that started all of this off. Not sure if this is the new vacuum break-in kind of problem or if I had a bad initial seal on the HEPA filter bag in the CT26 before I opened it back up the first time. In any event, I can't reproduce item #1. Since then I have been deluding myself into thinking the ShopVac™ was performing better (without cyclone) compared to the CT26. While the ShopVac™ is still slightly better than the CT26, when placed side by side, the two are very comparable in the amount of fine dust (what triggers the 0.5um scale on my Dylos) they emit. In summary, I highly recommend a cyclone in front of either one of these (unless you are working outside). It won't take long working with the CT26 in a confined space to build up an unhealthy level of fine dust. Yes, one can wear a respirator, but in my case my garage attaches to the house. Every time the door is opened, negative pressure is created sucking that fine dust into the home degrading IAQ.

Okay, if you read through all of that, then I definitely owe you a beer, or two or six. When are you coming to AZ so that I can thank you properly for all of your help? Sorry for taking up your time on this one...I sure owe you for all of your help here.

[reible]

The good part of this discussion is that I went ahead on ordered a meter. Not the one I had mentioned but a even cheaper one that one of the the youtubers I watch uses.

So far I've been reading dust in the bedroom, a lot of fine dust, I guess off bedding or just household dust??

mt1.jpg (133.3 KiB) Viewed 13907 times

mt2.jpg (140.37 KiB) Viewed 13907 times

Next time I go to the shop to make saw dust I'll take it along.

Ed

[RFGuy]

The good part of this discussion is that I went ahead on ordered a meter. Not the one I had mentioned but a even cheaper one that one of the the youtubers I watch uses.

So far I've been reading dust in the bedroom, a lot of fine dust, I guess off bedding or just household dust??

mt1.jpg

mt2.jpg

Next time I go to the shop to make saw dust I'll take it along.

Ed

Thanks Ed. Where did you get the meter from? I need one for inside my house and don't think I want to spend as much as a Dylos for it. The display on yours looks good. I see different ranges on different websites, but generally 0 to 12 for PM2.5 is considered "Good" for air quality. A reading of 17 would be in the "Moderate" category. The 2nd pic you show has the actual particle counts, whereas PM2.5 is mass/volume of air. Unfortunately the Dylos DC1100 model doesn't show PM2.5. I could estimate it based on the particle counts, but it doesn't have it built in to estimate it. Their model that does have PM2.5 is like $500. I don't know how accurate my Dylos is, or your unit, but hey if yours gives you both PM2.5 and particle count AND is cheaper, it is probably money well spent. Kudos.

For reference, the actual particle counts in my house vary wildly from 200-800 depending on the room, indoor cooking, dust infiltration through my old windows, outdoor level fluctuations, etc. (running AustinAir cleaners throughout house - desert is full of dust here). If I run the air cleaners on high in the bedrooms they quickly come down to <50, but I prefer to keep them on low for noise reasons. In my shop, I routinely keep my particle counts well below 200 at all times when using power tools. If I do hand sanding it spikes well above this, but as long as I keep dust control near a tool AND my ceiling air cleaner running then I maintain 100-200 particle counts. I could go and calculate that in PM2.5, but I am sure that is well in the "Good" range, though local to the tool I am sure it fluctuates quite a bit (Bill Pentz has the PM2.5 estimation calculation for the Dylos - https://billpentz.com/woodworking/cyclone/dylos.cfm).

Indoor Air Quality Chart (PM2.5):

IAQ.jpg (196.22 KiB) Viewed 13905 times

Dylos 0.5um Particle Count Air Quality Chart:

Dylos_chart.jpg (74.2 KiB) Viewed 13866 times

[reible]

Still haven't go this out to the shop. I need to get a power supply for it, I have it plugged into a strip with USB ports for now.

I got it here:

https://www.amazon.com/gp/product/B07DL ... UTF8&psc=1

Used the 5% off coupon to save a few more dollars, don't know how long that will be offered.

Ed

[RFGuy]

Thanks Ed. I ordered one. I have been wanting one of these for the house. Sometimes our air quality varies quite a bit here, so this will tell me when to kick up the speed on the air cleaners in the house. This unit has a nice LCD display and looks better than the Dylos and displays more. Surely can't beat the price on this one...

[sehast]

Let us know how this works for measuring dust levels in the shop. I have always wondered how well my dust collection and cleaners are performing. Since I don't know except for subjective visual observation, I always wear a dust mask anyway. The dust collection for some of the Festools I own is so good that it tempts me to not use the mask but I would like some verification.

[RFGuy]

I am quite impressed with this laser particle counter that Ed mentioned here. I did some A-B comparisons and snapped some pics below. I would definitely say this counter is in the same ballpark of measurement with my Dylos, but a lot cheaper. So Ed's counter (sorry I don't know the brand of this thing, so don't know what to call it), displays real time, continuous measurements so it is always changing. The Dylos displays a running average of the past 10 seconds, so I think this AND the variability of the local dust in air near each unit explains the differences. The Dylos does have an Analog style bar graph reading that fluctuates to indicate real time reading fluctuation...like a good DMM would have, but still this other unit has a very nice color display with good information. However, I have to say the particle counts are definitely in the ballpark and compare favorably between the two units IMHO. Also, Ed's counter goes down to 0.3um and has measurements for 0.5um, 1.0um, 2.5um, 5.0um, and 10.0um which is nice. In addition, Ed's counter has the estimation calculation built in for PM2.5, etc. and AQI so you get a little better idea of how the particle counts map to an actual air quality metric which is nice. The one annoying thing with Ed's counter though is if you have a very clean room, the PM2.5 can drop below 1 and then it shows it in red and the AQI switches from saying good air quality to bad. Must be a glitch in their programming, because obviously if the PM2.5 is <1 then that is good AQI.

Well, this is the first time I got around to using my Dylos DC1100 Pro model for what I paid the extra for on it...it has the ability to datalog to a PC, so I finally got around to measuring my Festool CT26E performance (no cyclone) with the Festool Domino DF500Q. I had the shop air good and clear before starting, then I started data capture and waited two minutes before starting. The room was stable and did not fluctuate during those first two minutes, then at 2.5 minutes I quickly cut 5 mortises (12mm deep). The CT26E turned on automatically and turned off automatically after the last mortise. I captured for 20 minutes and you can see my data capture in the graph below. I still think something is wrong. My small sensor on the Dylos measures particles 0.5um and up (large sensor is 2.5um and up). The HEPA filter on the CT26E is supposed to filter 99.99% of particles down to 0.3um. That 0.01% of dust particles coming out of the CT26E between 0.5um to 2.5um is an awful lot for 5 measly mortises. The mortises were clean and the Domino is clean inside and out. I could understand if I was sanding or something else with the CT26E, but it doesn't get much cleaner than using a Domino to cut, so I am back to thinking something is wrong with my CT26E. I am waiting on a response from Festool, but I know the holidays will probably delay it.

NOTE: For Dylos, the measurement on the left is the 0.5um sensor and the measurement on the right is the 2.5um sensor. The Dylos measured reading is 1/100 of what would be measured in a cubic foot of air. Presumably this new laser particle counter has a similar measurement to the Dylos, but no way to know since no documentation.

IMG_4508_2.jpg (127.6 KiB) Viewed 13524 times

IMG_4510_2.jpg (124.86 KiB) Viewed 13524 times

CT26E_graph.jpg (95.2 KiB) Viewed 13524 times

[sehast]

I am having a hard time understanding the data. How would you project the expected results? How bad were the the results that were measured? What is good, marginal and bad? 99.99% is the spec but unless you measure with no dust collection how do you know it was not meant? Sorry this is just something I just don't have much background on.

[RFGuy]

I am having a hard time understanding the data. How would you project the expected results? How bad were the the results that were measured? What is good, marginal and bad? 99.99% is the spec but unless you measure with no dust collection how do you know it was not meant? Sorry this is just something I just don't have much background on.

Good questions. Let me attempt to answer them. So, the 5 mortises that I cut produced a similar amount of in-air fine particulate dust in my shop as if I was running a ROS without dust collection, but using the dust trap (my Porter Cable has a kind of hard plastic one that is porous to let some air through - others may have a cloth dust bag). This is the worst case in my shop - sanding with a ROS without dust extraction (cutting functions produce much less fine dust into the shop air). So, imagine the amount of fine dust particulate that gets in the shop air from 5-10 minutes of ROS operation without using a DC or vacuum. That is comparable to what I get from cutting 5 mortises with the Domino while using dust extraction from the CT26E. That is how bad it is... I can't know how accurate either of these laser particle counters are. That is why I am only interested in relative measurements, e.g. if shop air was relatively clean to start with and then I do a cut, how much added dust in the air did it produce? I have no training in this, but I do have a good bit of time observing the Dylos in my shop doing various woodworking functions at different tools...so based on this, what I am seeing with the Festool doesn't feel right in comparison. Also, the Festool HEPA is supposed to extract 99.99% of fine particulate dust at 0.3um. Why 0.3um? Well, typically 0.3um is spec'ed for two reasons. One is that most HEPA filters have the worst efficiency (localized minima - see chart below) rating right around 0.3um (https://smartairfilters.com/en/blog/wha ... important/) and two is that this is the size particulate that is supposed to do the most damage in the lungs. So, if Festool specs their HEPA filter at 99.99% collection at 0.3um, that means only 0.01% of this fine dust particulate is getting through. You are right to ask well how much should that number be and unfortunately I can't answer that. I know my ShopVac™ running HEPA filter and HEPA bag (similar to Festool setup) is performing better than the Festool for less than 1/10 the cost. Your idea to measure without dust extraction is interesting, but I don't know that I am ready to just remove dust extraction entirely yet. The more complicated answer is measuring dust levels in the shop is problematic. I have the laser particle counter a good distance from the CT26E and the Domino. Without the blower on the CT26E expelling fine dust into the air, I kind of doubt the measurement profile will be the same for a no dust extraction measurement, although the local air around the Domino will be saturated. I have no air movement in the shop other than the blower exhaust on the CT26E. IF I do the no dust extraction test, I might need to capture for a much longer time for both with and without the CT26E, but then integrate the area under the curve to compare because a single point measurement isn't very useful for this kind of problem. Also, if the fine dust settles out before it makes it across the room to the laser counter, there could be more dust for that case that isn't counted because it settled out on the floor, workbench, etc. Well, I have rambled on enough here, so I should probably end this post. Festool claims this vacuum is suitable for use inside customers homes due to the HEPA filtration and superior dust extraction designed into their tools, but based on the measurements I have done this would be impossible. If all CT26E's are like mine, there would be so much fine dust particulate released into a home for a day of contracting that the home would be unlivable afterwards. Either something is wrong with my CT26E, or all of the CT26E's are NOT meeting their rated HEPA specifications, or this expectation of using the CT26E at jobsites inside customer's homes is complete marketing BS. Remember this is the #1 thing that Festool promotes on their tools is that it is clean enough to use inside customer's homes.

SAMPLE chart showing filter efficiency (NOT from Festool): just for illustration purposes

10.-Particle-Size-Capture-MERV-EN.png (29.9 KiB) Viewed 13470 times