Thread: Something different? Ducting a SHOP VAC – one happy chappy

Here you go



and the proposed changes are shown in green





To show it pictorially:

Thanks for the pics Brett, that makes it very clear.

The proposed 60 mm duct is throttled by the proposed 50 mm so unless you already have the 60 mm ducting, it's not going to make a lot of difference to use 50 mm ducting there. OTOH 60 mm won't hurt it.

Replacing 50 mm hose over smaller stuff where you can will help overall dust collection at source. However your air speed at source may drop so you may lose some big chips but you can be reassured that you will pick up more fines. Don't be fooled into then trying to increase air speed back at source by constricting the hose orifice or you will be right back where you started from.

Replacing the grey water diverters with Wyes and blast gates will also help.

After working with Festool gear all week on the jarrah bench project I can see why Festool use 27 mm hose and that is because it keeps the work area relatively clean of chips. I wish I had brought a particle detector with me so I could measure fines.

Thanks very much Bob, a great help.

Originally Posted by BobL

The proposed 60 mm duct is throttled by the proposed 50 mm so unless you already have the 60 mm ducting, it's not going to make a lot of difference to use 50 mm ducting there. OTOH 60 mm won't hurt it. Roger that. Will use 50mm pipe because it will be easier to join to 40mm (existence of suitable fittings etc)

Replacing 50 mm hose over smaller stuff where you can will help overall dust collection at source. However your air speed at source may drop so you may lose some big chips but you can be reassured that you will pick up more fines. Good, I'd rather get the fines, and just blow the chips off when necessary

Don't be fooled into then trying to increase air speed back at source by constricting the hose orifice or you will be right back where you started from. Understood

Replacing the grey water diverters with Wyes and blast gates will also help. Tell you what though - these GWDs seem to have a good seal. However, there is the smaller internal diameters which will cause restrictions at the Cyclone end in particular.

After working with Festool gear all week on the jarrah bench project I can see why Festool use 27 mm hose and that is because it keeps the work area relatively clean of chips. Yes, important for ergonomics, but not so good for the lungs.

When I did the womanometer testing a while back it didn't occur to me that I was going to suck the guts out (in?) of the cyclone bucket, and sure enough, it did. Permanently! This has meant of course that the capacity of the bucket was drastically reduced, and that the crease points were creating possible tear points. Not to mention being extremely difficult to unscrew the lid because the rim was out of shape.

There are no more cyclones of this type available in Oz, and even if there were, there were no spare buckets. So the fix had to come from within. I screwed 8 timber rods to it, with the head of the screw inside the bucket, and also with a little rubber washer under the head to keep the seal.

Sucksess!




Anyone who has one of these cyclones may wish to contemplate something similar, because as soon as you send the vac into overdrive the bucket sucks its guts in. A harder, thicker plastic for the bucket could prevent this, but they are what they are. Even in normal use you will have seen that the sides will cave in a little, and this means that the vac is doing work to cause this movement (which takes a reasonable amount of energy - try pushing it in yourself). This work means less work is being done on the actual sucking power. It may be a very small loss, and Bob may be able to comment, but it is nevetheless a loss. Bob knows a thing or two about loss.

Those small cyclones and chip collectors generally cause a pressure drop of 4.5" of H20 which is equivalent to 0.16 psi.

If the bucket is 18 tall and 14 in diam that makes a side surface area of 800 sq inches.

0.16 psi x 800 sq in = 128 lbs - no wonder the sides are caving in

Well, I've lived with this system for a year now, and I love it! Very convenient.

However, there has been room for improvement, and the first part of that was removing the cyclone. Unfortunately, when I did the Womanometer tests the life of the Cyclone was wrecked (they'll do that to you) as it imploded and the sides got weakened. I stiffened them up with some battens (as previously posted), but maybe the screws I used for that, or maybe it was the stress of being denied communication, but it started taking too much grunt out of the system, and that will never do.

So, to business. The Grey Water diverters were ok for redirecting airflow, but there was a little pressure loss with them - this became apparent at the drill press, with the two hose system there. I did a slight redesign, which took out about two metres of duct, and most significantly, replaced the GW diverters with blast gates that I made. Man, they are a blast - they are so easy to make, and so ridiculously effective and quick.

This first pic is the area adjacent to the Kapex, where I had the first GW div. before (at the vac end of the system).

This is in the position for the Drill Press end:



In the Kapex position:


Quite simple - you just slide the tongue, which has a hole in it big enough to cover the outlets, to the position required. The MDF enclosure is glued together around the tongue for a tight fit (using just enough glue to avoid squeeze out) and then the tongue is knocked out while the glue dries.

Then, just sand the tongue until it's a nice, but tightish, fit and slide back in. Label it, and Robert's your relation. A good improvement would be to but a stopping tab on each end for speed of operation (hey, I run a tight, fast ship here - you should see just how quickly I can achieve very little).

Up at the Drill Press end, I have abandoned the fixed hose support (because it was a bloody PITA - forever getting in the way). The invention of the new, and spectacular, Bessey Toggle clamps has meant that clamping a job is really quick now. That means that I can just operate the vac hose in a freeform way with my (now) free left hand, which often used to help in clamping some jobs in the pre-Bessey Toggle clamp days. One thing leads to another.

Also, at the DP end I have taken out the last 2 metres of duct, and just come straight down from the ceiling, adjacent to the mid-bench outlet, which I usually leaved capped. The blast gate going to the DP looks like this:


When I want to use the mid-bench outlet I just slide the tongue in, and uncap.



The point about these DIY blast gates is that they are custom made for your sizes and requirements, and they are highly effective and efficient, in all senses.

It is likely that I will change this ducting system for a 65mm pipe (currently 40mm). If I do that then I will make an all-in-one blast gate for the DP/mid-bench combo like the first pic.

I will also do some work on this other new part:


Yep, the fabled Festool Y-front. Don't forget to gaff them up - they leak like a sieve. This goes off to the CMS Table saw rig, which houses a TS75. There's a 36mm hose goes to the usual place on the TS75, and a 27mm hose goes off to the blade cover.

At the other end of this, the duct just goes into the vac:


That's the old Cyclone hose being made use of. I found that i had to glue the hose into those grey fittings as there were leaks there too. The duct is only about a metre long, and is just for reach. Normally the Y goes straight into the vac but it means the CMS table has to be inconveniently close (my vac is fixed position, off the floor), and so there are also hoses at thigh height - not a good idea).

The top part of the CMS doesn't have fabulous dust capture, particularly on a 70mm deep cut. You can very quickly end up with a tidy pile of dust on the table. There are three possible solutions to this, and maybe a part of all three could be employed:
1. Use 50mm & 36mm hose instead of 36mm & 27mm.
2. Introduce a Big-Gulp on a two HP Dust Extractor (you know, the big ones) standing off the side of the table
3. Introduce a third hose, and a blast gate at the Y. Because I only use the CT vac with remote control power socket it allows me to run the saw off the vac, but in the manual mode (ok, it's an extra button to push, but just hang on for a sec). This will allow me to turn the saw off at the CMS switch, and the vac keeps running. Flick the blast gate to the overhead (third, and to be implemented) hose, and clean off the deck, and then remote off the vac. If I wish to skip cleaning the deck I can just remote off the vac which kills the saw as well (the CMS has a zero volt switch, so no worries about the saw coming to life next time).

I must say that I really dig using the vac with a remote control, although of course there are plenty of times when I use the tool triggering too, such as sanding. For that task I can just use a very short hose going to the mid-bench or DP outlet (about 4-5 feet long). That works well too because there's less hose to get caught up in things, and it takes off to the ceiling - less chance of wiping out whatever is on the bench with the hose swishing around. Using the remote becomes second nature after a while, and it allows you to alter the after tool time to suit what's going on, and oops, just need to get those few critical chips I missed without turning the tool back on.

Cheers
FF

Brett

You know what I like about your setup? The fact that it is continually evolving and nothing is set in concrete. If you find something is not working, you just go about resolving it. I know how cramped your workshop is having seen it at the BM Get Together so I am impressed at how neat and tidy you have made everything.

I might have to put some time into my own systems .

On the CMS I think they are one of the problem machines. Dust collection as supplied varies from poor to diabolical. My own Bosch saw is diabolical.

Regards
Paul

Cheers Paul. By all accounts the CMS in Router Table mode is very effective at DE. Ripping a piece of wood (say) 20mm thick doesn't leave too much dust, but the deeper cuts produced a fair amount that didn't get removed. Mind you, it did all seem to collect in two places - one on the table itself, and the rest went everywhere else .

I reckon a Big Gulp standing off the side would be really effective (as long as they work as specified), but may also be a PITA for getting in the way.

Originally Posted by FenceFurniture

Cheers Paul. By all accounts the CMS in Router Table mode is very effective at DE. Ripping a piece of wood (say) 20mm thick doesn't leave too much dust, but the deeper cuts produced a fair amount that didn't get removed. Mind you, it did all seem to collect in two places - one on the table itself, and the rest went everywhere else .

I reckon a Big Gulp standing off the side would be really effective (as long as they work as specified), but may also be a PITA for getting in the way.

I used to have a Big Gulp (), but Simon ended up with it for use with his lathe. I think it would help with two provisos. Firstly that they are big and tend to get in the way particularly if left as a permanent setup. Secondly, I'm not sure if you would be able to maintain sufficient airflow with your smaller piping. They are set up for 100mm. Others who have better experience of the airflow dynamics may be able to better advise on that.

Regards
Paul

Originally Posted by Bushmiller

Brett

You know what I like about your setup? The fact that it is continually evolving and nothing is set in concrete. If you find something is not working, you just go about resolving it. . . . . .

Love the blast gates too.

Originally Posted by Bushmiller

Secondly, I'm not sure if you would be able to maintain sufficient airflow with your smaller piping. They are set up for 100mm.

No, what I mean is I would run the BG off the big dust extractor (in tandem with the CT Vac).

I am considering doing Bob's mod to the DE to put in a 6" inlet. The outlet is square and so can't be modified but it's 30 square inches, so a 6" inlet will be 28 sq.in as opposed to the current 5" inlet with only 17 sq.in.

I'll need to find someone who can cut a nice round 6" hole in the plate, but that shouldn't be too hard. Then silicon a flange into it, etc, etc.

In fact, I may well investigate using the big dusty for all DE on the CMS - again by remote control (it has no ZVR switch either). The trouble with the CMS is that the blade cover outlet is a shocking choke point. You have to distort the fitting into an oval to shove it inside the hood, and it would be less than a square inch (closer to half). I have worked out that the 36mm fitting will go on over rather than into the hood, but it would only be held by about 7mm, so I reckon it will slip off.

The whole DE system on the CMS for sawing needs a workover, I believe. The bottom outlet (from the usual extraction point of the saw) is fine but would no doubt benefit from going up to 50mm hose. However, the top part......

It amazes me how Festool get their engineering so good, only to be let down by ergonomics - sometimes glaringly so. Extraction hoses going into outlets reduce the size dramatically. They recommend a 27mm hose for the Kapex SCMS, and yet it seems to be common knowledge that a 36mm hose works much better. So I geuss a 50mm hose would be even better still, given that a drop saw puts out a lot of concentrated dust. That's another mod I'll be trying, but I have to get some more parts for that (hence one reason why I'm considering 65mm ducting).

Originally Posted by BobL

Love the blast gates too.

Cheers Bob. Actually, you should - they're your design! (well the big one was)

Originally Posted by FenceFurniture

No, what I mean is I would run the BG off the big dust extractor (in tandem with the CT Vac).
I am considering doing Bob's mod to the DE to put in a 6" inlet. The outlet is square and so can't be modified but it's 30 square inches, so a 6" inlet will be 28 sq.in as opposed to the current 5" inlet with only 17 sq.in. I'll need to find someone who can cut a nice round 6" hole in the plate, but that shouldn't be too hard. Then silicon a flange into it, etc, etc.

FWIW I replace the existing inlet plate with a piece of steel shell from a clothes dryer and just cut the circles with a jigsaw with a metal blade. If you want to reduce the chatter you could clamp a 6 mm sheet of mdf behind it but I didn't bother. Then I used an angle grinder with a fine flap wheel to round over the edges. The inlet hole did not need to be exactly round because that was done by adding the reverse bell-mouth entry which was made out of 32 mm thick melamine. Two layers of 18 mm MDF would be even better.

Thanks Bob.