Best Pricing locations for dust collection piping/hoses

[Alan in Little Washington]

One problem I do find is that most tools are not well sealed. Even with a dust collector attached to the machine's port there are still many places for the chips and dust to escape. For example, my table saw is an older model without any sort of dust port. I had to build this into the base and found it helpful to also use insulating spray foam to seal around the table top and base. That made a big difference.
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You might want to rethink that. You must leave sufficient opening(s) to allow for make-up air- No air in = no air or dust out!! It can be like a closed blast gate- no flow! A tablesaw of any type is problematic. No amount of suction on the cabinet will pull dust down through the blade insert or from the blade gullets, so much dust is thrown off the top of the blade (at the operator) at a speed faster than the velocity of DC air. A barrier + collection (over-blade pick-up) is necessary. As for dust that does get thrown from the blade into the cabinet, many people block all the little access holes between the cabinet and the cast iron top, slots around the elevation and tilt handles, etc.- not good!- air must be allowed to enter.

 

[JimD]

Alan,

I agree with most of what you said but I disagree with your comments on dust collection at the table saw. The difference on airflow through the cabinet with a DC, regardless of the venting area, and without it will more than make up for some sealing of the openings. We also have to remember that a DC is a high volume, low pressure, air mover, however, so if you seal up the cabinet too well, the airflow will be greatly reduced but still more than what would occur just due to blade movement.

I kind of agree that you can't get all the dust without overhead pickup but I tested the effect of different sized openings in the throat plate on my now "old" table saw, a Ryobi BT3100. I have an articulated cover on the back to block off that opening and magnets over the front openings to force as much air through the throat plate as possible. Dust collection if via a shop vac, a low volume higher pressure air mover. It never overheats. But I found that opening the back of the throat plate reduces the dust on the top significantly. On my new SawStop, I cut generous 1/4 wide openings in the Infinity throat plate inserts for the riving knife because of this effect. With the huge cabinet openings, my shop vac will not move enough air for this to make a lot of difference but when I hook up a DC, I think it will. Interestingly, even though the cabinet is quite open, the motor on my SawStop (1.75hp) has overheated once already. A DC should cure that too.

I think larger throat plate openings are worthwhile and help with dust on top (edge cuts remain bad, however, for dust) and closing off the cabinet will not overheat the saw if you are using a DC. I intend to try the SawStop without sealing the openings, however, when I add a DC and see if the DC doesn't move enough air that I get reasonable suction at the throat plate. If I do, I will leave the cabinet openings as they are.

Jim

 

[Alan in Little Washington]

Alan,

I agree with most of what you said but I disagree with your comments on dust collection at the table saw. The difference on airflow through the cabinet with a DC, regardless of the venting area, and without it will more than make up for some sealing of the openings. We also have to remember that a DC is a high volume, low pressure, air mover, however, so if you seal up the cabinet too well, the airflow will be greatly reduced but still more than what would occur just due to blade movement.

I'm not following. I think you misunderstood what I said which is, if you block off ALL the misc openings in the cabinet and rely just on the blade insert (standard, zero clearance, or even dado whose openings on either side of the blade are just a fraction of the sq area of a 6" or even 4" duct) as your only source of makeup air, you are significantly throttling the air flow and only getting a fraction of the CFM through the saw and into the duct. In fact, the flow may be so impacted, you might end up with dust and chips settling out of the air stream, marginal separation in the cyclone, etc. Depending on the configuration of the cabinet floor (flat, steeply sloped, funnel shaped, etc.) you may still remove a certain amount of dust. But do the math- just take a typical airspeed (you can use 2500 or 4000 fpm for this comparison) and the duct/port diam. at your saw to compute max possible CFM. Then do the same with the total area of open space around the blade (2 or 3 sq in.?)!! Again, my extreme comparison still applies- CFM through a machine + duct = flow vs CFM through a duct with blast gate closed = 0 flow.

I kind of agree that you can't get all the dust without overhead pickup but I tested the effect of different sized openings in the throat plate on my now "old" table saw, a Ryobi BT3100. I have an articulated cover on the back to block off that opening and magnets over the front openings to force as much air through the throat plate as possible. Dust collection if via a shop vac, a low volume higher pressure air mover. It never overheats. But I found that opening the back of the throat plate reduces the dust on the top significantly. On my new SawStop, I cut generous 1/4 wide openings in the Infinity throat plate inserts for the riving knife because of this effect. With the huge cabinet openings, my shop vac will not move enough air for this to make a lot of difference but when I hook up a DC, I think it will. Interestingly, even though the cabinet is quite open, the motor on my SawStop (1.75hp) has overheated once already. A DC should cure that too.

I think larger throat plate openings are worthwhile and help with dust on top (edge cuts remain bad, however, for dust) and closing off the cabinet will not overheat the saw if you are using a DC. I intend to try the SawStop without sealing the openings, however, when I add a DC and see if the DC doesn't move enough air that I get reasonable suction at the throat plate. If I do, I will leave the cabinet openings as they are.

Jim

You are correct, a shopvac is totally unsuited for a cabinet saw. Shopvac= 80 CFM mx vs DC = 350+ CFM (hopefully).

 

[Gotcha6]

I too was concerned with creating a situation that might collapse the piping, so I installed a 'vacuum relief valve' in my pipe. I came off the 4" horizontal run with a 4" tee turned upwards, then put a 180 degree bend into it so it wouldn't become clogged with chips & dust. Inside of a 4' x 3" reducer I taper fitted a piece of 1/2" thick UHMW I had so that it would seat into the fitting. After drilling a center hole in this, I installed some 3/8" threaded rod and added washers until the valve would 'pop up' whenever sufficient vacuum was achieved on the system. Once the problem is solved, the valve will re seat itself. I had a photo of it in my gallery, but......:dontknow::dontknow:

 

[JimD]

It sounds like our views are more aligned than I thought. I agree that operating a DC without adequate airflow will cause issues. I remain doubtful that cooling of the table saw motor is one but I agree completely that sufficient flow is necessary in the DC's ducts to move the dust and chips. My experience trying to seal up my table saws is that I wasn't terribly successful - they still leaked significantly. But if I seal up the SawStop, I will probably use a cheap wind speed meter to check airflow.

 

[Warren]

I've has a 5 hp cyclone for about 10 years. I used 6" PVC white drainage pipe from Agri-Supply. It comes in 10 ft. lengths with one end flared to fit the next section. All the reducers to 4" at machines, wyes, and elbows were metal and came from PSI. If you want, run metal tape down the length (i.d.) of all plastic parts to ground static build-up. As for manual blast gates, make your own using plywood and cut-off pipe (you'll have plenty of pipe cutoffs - diy plans on the web). Finally, seal all joints with white RTV.

Don't overlook using 100v to 220v relay to start cyclone (only used to activate the n.o. 220 circuit). Then go to big box store and buy a lamp remote control to activate the collector.