If I knew what I know now, I wouldn't buy the Midi or the Ct-15. My base minimum would be the CT 26. The spec sheet doesn't show the suction significantly higher, but in the real time test it is way better. I don't think I've ever experienced suction loss on my 26 or 48. Only improvement would be the bigger hose. Definitely only use festool bags. If you can get the cyclone, it will fill one bag in place of 10.
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mino
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Yup.Maahfu said:
The biggest difference is the surface area of the bag which comes in contact with the main filter. That is where the main "show" is happening. On the CT26/36/48 series this area is almost twice as big and it does show in suction persistence.
Yet the 15/MINI*MIDI series are still great vacs. Just not as heavy duty (as in persistent for prolonged loads at full power) as their bigger brothers. In practice, unless one needs the full power, it is enough to use a bit higher setting on the smaller vacs. The bigger ones I mostly run on the mid settings.
Suction loss will happen regardless of what CT model you use once the bag is filled near its full capacity. If the shop procedures or environment allows it, the cyclone is the best companion for any shop vacs or extractors, which puts off any suction loss until the bucket is filled or so.
ChuckS said:
Sure, but if you were to play a graph to visualize suction loss on the CT as function of [% bag filled]... with plaster or concrete dust you will see it dropped straight from the start while with ripping wood you will see it stay nearly unchanged until it starts compacting the stuff in the hose..
Unless I misunderstood your %, I find it hard to see how a bag full of 10% of paster could cause more suction loss than a bag full of 99% of sanding dust. The majority of CT users don't use hand planes on a regular basis at all. I put my plane shavings in my compost bin.
squall_line
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Something to keep in mind is the way the plaster (or concrete) fills the micropores on the filter bag compared to wood dust. So it turns out to be not as much about how much plaster is in a bag vs. how much has gone into the bag while running and caked up the inside of the bag.
mino
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Practice rules. I am confident coen has a 10+ projects behind him backing his statements.ChuckS said:
Plaster or concrete dust will clog-up the micropores of the bag and Self-Clean will not help as the particles are smaller than its net. This will affect the suction already at the 5-10% full, but is actually completely INDEPENDENT of the bag fullness. If one had 50% full bag from wood work, then put in 10% plaster dust, he would clog it at 60%, not 10% as new one.
Festool SelfClean bags lining is anti-stick and works for particles bigger than a certain size only, those will fall down by gravity when the vac is stopped. Is also why the main filter is horizontally above the tub. The bag fullness, per se, does not affect the suction performance. That is also why the Festool vacs are so great for cyclone use.
What, I believe, was coen's original point is that anecdotal evidence from a wood-dust-producer is not universally applicable. Reason being that wood dust, including "microdust" from sanding, is actually fairly large compared to plaster dust particles and thus the anti-stick SelfClean bags can fully show their prowes.
It is no coincidence that Festool was the /only ?/ one to bother with the SelfClean gbags tech - despite it being effective only on "bigger" particles. Most other vac makers do not sell predominantly to woodworkers ... thus the benefts of SelfClean would not be interesting to big parts of their customer base.
Short but concise:
So far, no concrete evidence (pun not intended) has been offered to support the claim that 10%plaster would cause more suction loss than 99%of sanding dust in a CT dust extractor. I am not buying such a % claim nor should anyone unless a test is done to prove it.
Essays after essays alone, I'm afraid, won't be enough as scientific evidence.
Essays after essays alone, I'm afraid, won't be enough as scientific evidence.
ChuckS said:
Lost art. I have a festool cyclone on every vac I own. So I just dump the bin in the compost bin too. It has been mentioned before, a CT vacumn needs a dust deputy or cyclone of some sort or you will be changing bags alot. I wasn't a fan of the reusable bags.
Same here. Except for the shop vac for the SawStop dust collection blade guard, all other shop vacs in my shop are used in conjunction with a Dust Deputy. I can often tell how full the plastic DD bin is while it's more a trial and error thing with the CT15 bag.
ChuckS said:
The 99% was from wood shavings / saw dust, not from sanding dust.
The 10% on plaster / concrete dust you did read correct. That type of dust tends to 'seal' the bag, reducing airflow massively. It only has to "seal" the surface that contacts the filter and it's basicly game over.
My CTL-22 that is living a sedentary life beneath the CS-50 (=table saw) often gets it's bag so full that the wood dust is in the hose; only then a clear drop in suction is noticed.
My CTL-26 and CTL-Midi I that travel with my tools from time to time get to experience a nastier life, especially when connected to my Metabo MFE-65 (look it up). The loss in suction is insane from the type of dust that that thing creates while cutting into concrete, sand-lime brick and clay bricks. I like to joke that it turns wall into gas. But if you don't extract the output... that 'gas' is definitely not transparent... On the Midi-I the drop off is steeper than on the CTL 26 but can be somewhat reversed by using the filter clean lever.
No I have no peer reviewed measurements on the suction loss, it's just an observed reality. A CTL 26 bag 80% full with plywood sawdust will perform visually better than a bag that was filled with 15% wallchaser dust.
Mind you; those uses (sanding plaster, wallchasing) are typically the use cases for a bagless vac with filter cleaning. As of now... I don't own such a machine, but if wallchasing was a bigger part of my life.. I definitely would.
A cyclone won't do much, as it traps the "big // heavy" dust; particles having a low [CdA/weight] score. It is the tiniest particles that still end up in the bag and those are the same particles responsible for "sealing" it.
