Failed enhancement, Kapex to stationary extractor

[Mauri Motti]

For a few months now I'm the happy user of a Felder table saw/ spindle moulder combo and a surface/ thickness planer combo. I have a wall hung extractor which is the Felder AF-22. While designing the ducting I realized that it runs overhead the Kapex and decided to include it to the same extractor. I did/ do not have a designated CTL for the Kapex though it has been on my wish list for a long time.

I do have a CTL 26 E but don't want it stationary at the Kapex and... yeah well, ehm, I'm to lazy to drag it from too to tool all the time. Guess you know how it is, you start with good intentions and do the dragging around the thing at first but then, somewhere in the middle of a project you have to make just a few more cuts on the Kapex and...give up hailing the CTL around. At least I do.

Anyways, hooked up to the Felder extractor it does not nearly work out as well as as the CTL does the job and I don't really understand why that is..? Dust is extracted really well from the saw and the planer but not at the Kapex and it is (even) closest located to the extractor. The "main" pipe running to the extractor is 160mm and where it comes to the planer and saw it funnels to 125mm pipes and hoses. From the Kapex it goes from a 50mm hose into a 100mm pipe to the "main" 160mm pipe, still following me? The is no blast gate at the Kapex so when I run, say the saw, the hose to the Kapex is open but it does not bother the suction capacity from the saw or planer.

Here's a video on the matter. Please note that I cleaned the table before making the cuts. Also, I pause for a moment to show how the extractor runs for another 10 seconds after the saw has been turned off. (this is meant to be, the extractor turns on when a tool is started and runs a for about 10 sec. after a tool has been switched off) Also, Also (pps, lol) I have tried to include two images in this tread that show the ducting as it doesn't in the video but I'm having trouble with it and had to leave them out.



(spelling and additional info edit)

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[PeterK]

I am sure someone else can explain this far better than I.
A central dust collection system like an Oneida with cyclone is designed to be high volume but at low suction - meaning the static lift rating is in the 6-10 inch range if I remember correctly. A portable dust collector like the Festool CT series operates with far less volume of air being drawn but at far higher suction so the static lift is up around 120-130 inches.

 

[semenza]

Yup.  Basically it can't draw enough air through the down sized pipe on the Kapex.

Seth

 

[joraft]

The CT is a dust extractor and the Felder is a dust collector.

Using a dust collector on a miter saw effectively usually requires building some kind of hood:

 

[Mauri Motti]

Thanks all, this is useful feedback. "The CT is a dust extractor and the Felder is a dust collector" I totally did not realize this until now!
I didn't plan on building a hood around the Kapex though. Guess I'll be left with an exceptionally dusty spot in the shop that will get vacuumed from time to time.

 

[joraft]

... I didn't plan on building a hood around the Kapex though. Guess I'll be left with an exceptionally dusty spot in the shop that will get vacuumed from time to time.

Mauri, for about $20 (USD) you can install a small hood that may work better than the setup you have now.

Amazon.com

 

[JayStPeter]

This may not apply to a Kapex, but I had to mess around to get the DC to work with my CMS.  My CMS does work OK with a regular festool hose stuck in it with a vac, so dunno.  But, my CMS doesn't collect quite as well as a Kapex.

I had to run a larger, 2.5" in my case, hose all the way to the CMS.  I found a rubber plug of some sort for typical 2.5" hose, I think at the big box and cut a hole for the cms port.  I found running a smaller diameter hose from the blast gate to the CMS cut the flow way too much.  So, my system goes 6" to 4" blast gate to around 6' of 2.5" hose to significantly smaller port right at the tool.  I also have to open a larger blast gate to avoid starving my dust collector.  I open my 6" table saw gate also for best flow.  Collects about the same amount as a shop vac connection.  You may want to play around with some duct tape and your other blast gates and see if you can get it to work reasonably before giving up.  It's much easier to have the DC work for everything that doesn't move around than to have to drag the vac back and forth from the portable tools bench to the miter saw station. 

 

[Kev]

You can probably pick up a cheap air flow meter to prove this - but the dedicated DC creates far more suction.

Option ... get a free hose for the Felder with a typical vac nozzle and spread some sand on the floor ... try lifting it with the felder then the festool. You should see very different results.

Best solution could be to dedicate at Festool CT (or somilar) and use the felder plumbing with a hood arrangement for the loose stuff. Anything else will be complicated! Bonus option would be to ad something like a dust deputy to the mix.

My thoughts anyway  [cool]

 

[Mauri Motti]

Hi Kev,

I thought about getting an airflow meter as I would also be interested to know about the extractors dust collectors capacity with, say, the bags more than half full.
Will have to search online for it as I would not have any idea where to find one locally.

Thanks a bunch to Peter Halle who uploaded the pictures in this first post. I wanted to add them as the pics show the distance from a tool to the collector from which I thought this is of importance. But the issue starts making sense now having learned about low and high suction, airflow etc. Luckily there are suggestions here for improvements in it's current setup.

If one has more suggestions, please keep em coming!

Regards,
Mauri

 

[jakiiski]

Air flow vs. air pressure - those are two different things and the vac ads etc. typically display those two as separate values. A proper vacuum cleaner is created a pressure of 2500 mBar typically. Airflow is then measured as cubic meters per hour or litres/second. You can also get a high pressure blower to your dust collector, but they can't deal with any solid particles -> so you have to have a cycle or similar before to separate any of the larger stuff. The typical dust collectors are producing only 1500 mBar of pressure but they are able to handle the random occasional piece of debris that can flow through them w/o any damage to the fan itself.

 

[greg mann]

It is hard to tell from the picture because the fitting is behind the main duct but, if you have a 45 degree entrance ramp to the main duct, you could try opening a blast gate one tool further away from your collector than the Kapex and see if the added volume will pull more airflow up from the Kapex. I think this is what Jay said helped his system. I have a simialr problem using my dust collector with the CS70. Even though it pulls from above and below the table it just restricts the air-flow too much because it all travels through the 50mm hose designed to work with a Festool DC. I get better performance with the Festool. If I was a farmer I would be tractor poor. Instead I am dust extractor poor. Two Festools, three Feins, one Rigid SV, and a single stage Dust Collector. The Feins were the result of a deal I could not pass up. The problem is they are all just convenient enough to keep me from really engineering a good primary solution for my staionary tools like the OP has developed. Some day.....