CT Midi -- poor performance?

[serge0n]

My CT Midi is not performing to my expectations. I wonder if my expectations are too high or if I should replace it with a CT26? Have any of you upgraded from Midi to CT 26 and had a noticeable improvement in dust removal?

Let me explain.

I've seen videos of people using Kapex with CT 26 where around 80% of dust was removed. When I use my Kapex, it feels like only 50-60% of dust is removed. I tried it with a brand new bag, 27 mm and 36 mm hose, the results are almost identical - miter saw table and degree scale is covered with quite a bit of sawdust just after 10 cutoffs on a 2x4. Many shavings land on the floor and the wall behind the Kapex as well. It looks like a sawmill after 100 cuts. I have another miter saw, a cordless Ridgid 7 1/4" and dust extraction is very similar to Kapex. I thought Kapex is supposed to be superior in terms of dust collection, especially vs a "lowly" Ridgid. But that's not my experience.

Further, if I use CT Midi with CMS OF, the 27 mm end of the twin 27/36 mm CMS hose has minimal suction, it doesn't even stick to my palm if I leave the 36 mm end open. If I plug it into a Fein vac, the suction on the 27 mm end isn't great, but at least it sticks to the palm of my hand! So when I'm cutting rail and style on CMS with the Midi, quite a few shavings escape. If I hook it up to my DIY router table paired with a homemade twin hose and a Triton router, barely a speck escapes.

When I'm cleaning my shop using the Midi, I often have to go over the pile of sawdust 2 or 3 times to get every speck. Sometimes I have to do it slowly to really pick everything up.

The extractor works fine on my sanders, TS55, Carvex, even Dewalt's cordless table saw.

Would CT 26 perform much better at general clean up, using Kapex and CMS?

 

[Birdhunter]

Your description of the vac performance sounds like there is something amiss.

I can’t tell the difference between the suction between my Festool vac and my Fein vac. Both are very strong until the bag gets full.

I get an estimated 90 percent dust collection on my Kapex making a 90 degree cut.

If I think my vac hose might have an obstruction, I drop a weighted rod down the hose. It has gotten blocked and the suction really sucks.

 

[semenza]

I think the most telling part of your description is that it has trouble picking up stuff on the floor. Estimates of DC from the Kapex can be subjective (though the DC should be very good) and the amount DC can vary depending the speed of cut, etc.  But if it has trouble picking up dust on the floor, then something is wrong.

Seth

 

[RustE]

I'm leaning towards the hose being the culprit.  Either an obstruction (as mentioned by Birdhunter), a hole, or a crack.

Another thought is the filter element in both machines might be due for replacement.

I have a vague recollection that an earlier version of CT Midi was not as powerful as the CT 26, in terms of CFM.  Unfortunately I don't recall the specifics about manufacture dates or model numbers.

 

[bertv]

Valid points made by the first responders here… I would like to add another one: if there is a lot of fine dust involved, the bag will kind of clog up, diminishing the suction strength. Put in a fresh bag and see if that makes a difference.

 

[RKA]

You can try pulling out the HEPA filters as well, and see if that restores the performance.  They may have gotten clogged with debris or might be obstructed. 

 

[serge0n]

I can’t tell the difference between the suction between my Festool vac and my Fein vac.

Thank you for this comment, it tells me something may not be right with my Midi as I can definitely tell that my Fein Turbo I is more powerful.

I will try what you and others have suggested and inspect the hose for obstructions.

I'm leaning towards the hose being the culprit.  Either an obstruction (as mentioned by Birdhunter), a hole, or a crack.

Another thought is the filter element in both machines might be due for replacement.

I have a vague recollection that an earlier version of CT Midi was not as powerful as the CT 26, in terms of CFM.  Unfortunately I don't recall the specifics about manufacture dates or model numbers.

Thanks, definitely could be a crack! This vac is old and the hose is pretty beat up. I'll fill it up with water and see if there are any leaks.

Can you visually tell that the filter is up for replacement? Both filters (HEPA and pre-filter) looks like new.

Regarding the Midi version, I called Festool and asked them to look it up based on the serial number. They told me it has the same suction as CT 26, so it's not one of those earlier Midis.

[member=5467]Bert Vanderveen[/member] I tried testing with a brand new bag and the result were only a tiny bit better.

[member=21249]RKA[/member] Good suggestion, thank you. Can I run it without the HEPA filter without fine dust buildup inside the vac?

 

[RKA]

For testing, yes you can run it without the hepa.  For day to day use, just put the hepa back in. 

You mentioned something about a pre-filter up above.  What are you referring to?  The air should go through the bag, through the hepa filter, through the motor and get exhausted out of the unit. 

 

[Gregor]

Possibly a stupid question, but: have you turned down the suction on the midi and forgot to turn it up again?

Apart from that:
An as short as possible 36mm hose with as less bends as possible (as each increases turbulence, thus lowers airflow - so stay away from 90° hose connectors) works best for the Kapex. Giving the CT the time it needs to spin up fully after starting the saw (which is also good for the Kapex as it is given time to fully spin up the blade and unloaded runtime in which the motor will be cooled effectively) also helps increasing extraction amount quite a bit.
Sure: waiting for the CT will take a second or two more each cut, but IMHO worth it.

On the CMS-OF I also at times see chips flying, both with a MIDI and a CTL 36, unless the cutter is fully covered by the workpiece and the only opening being toward the the gap in the fence (where the 36mm hose is connected).

 

[yetihunter]

My CT Mini loses suction analogous to the bag getting fuller.  I toss it at half full. 
My CT 36 takes a longer time to see a reduction in performance.

One has a bigger bag than the other.  That is the reason. 

 

[BJM9818]

I have a Midi from 2006, Midi from 2014, CT36 and a CT36AC.

I replaced the hose garage on the old Midi,some how it cracked haha,and can tell the difference between the old and new one. Forget when they started using the same vac motor in every model but it was a few years back.

If you have a 10’ piece of copper pipe or similar shove it through the vac hose. Most likely you have something stuck preventing 100% flow.  I also change out my bags fairly often.