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Woodworker
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Discussion Starter #22 (Edited)
rrbrown said:
A quick check of how much more air flow a canister filter can create over the bag is remove your filters all together and see how much more suction is at the tool port now. (no need to actually cut anything but check the suction).

It should be quite a big difference and by adding the canister filter you would get closer to the no filter range of airflow. I checked mine as best i could and there is a difference but not as big of one as I thought, but I have 30 micron bags that I thought were 2 micron. However when I removed the 4" y connector at the DC and checked it, it seamed a little more noticeable.

My plan is still to switch to a 6" main line and reduce to 4" at each tool port. I also will get a canister filter. I also plan on finding or making something to test the air flow as is with the canister filter and then again with the larger duct. For now I plan on making a dial indicator that will have a 3" plastic ball attached to a string or wire. If anyone has a better idea about how to test it please let me know.
rrbrown
I talked to an engineering buddy of mine about measuring airflow, and he recommend that a simple "U-tube Manometer" would be simple and accurate.

A good link is:

http://www.engineeringtoolbox.com/u-tube-manometer-d_611.html


A simple application for use on a dust duct would be a clear tube attached to a board in a u shape, with some water at the bottom (aprox 5' - 6' long may need to be longer, we just don't want to suck out the water just move it). One end opened and the other attached to cap, with a hole to pass the air flow.

Mark the resting point of the water and up from there in 1" increments.

Turn on your dust collector and see how much the water moves (add a bit of dye to the water for better visability). That is your height.

Use the formula from the the web site above and you have your specific gravity measurement.

You can then move the Manometer to any of your tool ports to measure the static pressure.

I hope this helps
-Gorilla
 

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rrbrown
I talked to an engineering buddy of mine about measuring airflow, and he recommend that a simple "U-tube Manometer" would be simple and accurate.

A good link is:

http://www.engineeringtoolbox.com/u-tube-manometer-d_611.html


A simple application for use on a dust duct would be a clear tube attached to a board in a u shape, with some water at the bottom (aprox 5' - 6' long may need to be longer, we just don't want to suck out the water just move it). One end opened and the other attached to cap, with a hole to pass the air flow.

Mark the resting point of the water and up from there in 1" increments.

Turn on your dust collector and see how much the water moves (add a bit of dye to the water for better visability). That is your height.

Use the formula from the the web site above and you have your specific gravity measurement.

You can then move the Manometer to any of your tool ports to measure the static pressure.

I hope this helps
-Gorilla
Thank, I'll look into it
 

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I have some new info to consider. I'm a big fan of the PVC pipe but while at a wood turning meeting at the local Machine sales company (PMC) he brought up an interesting point. Although he agrees static in PVC is not an explosion risk for the small home shop. He did say that the static build up actually works against the air flow slowing it down. I'm not sure I agree totally but It is allot more plausible then the explosion risk theory. Any thoughts?
 

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I hooked up dust collector to table saw and am not satisfied. Hook up on power miter saw and radial arm works well but not table saw hook up... I am thinking about redoing the hood with 2" clear hose and trying to find a clear hood...You can't see what you are doing and the hood doesn't do a good job of picking anything up.
Table saw is about 5 feet from the cylone which is next to the collector.
Other tools are 12 to 18' from the collector.

Any suggestions.
 

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I hooked up dust collector to table saw and am not satisfied. Hook up on power miter saw and radial arm works well but not table saw hook up... I am thinking about redoing the hood with 2" clear hose and trying to find a clear hood...You can't see what you are doing and the hood doesn't do a good job of picking anything up.
Table saw is about 5 feet from the cylone which is next to the collector.
Other tools are 12 to 18' from the collector.

Any suggestions.
It looks like your running (2) 4" hoses of that single trunk. Unless you have a 6" trunk line from DC through the chip collector and then to the saw, You will have problems with (2) connections on one tool. I have a 4 and a 2 on some tools and it works ok but I'm switching to a 6" trunk line myself.

What size trunk line is it? what type DC?

What size trunk line between chip collector and DC?

I agree that you need a clear hood but also one with a 2 1/2" hose fitting.
 

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where's my table saw?
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I don't think that will work

You need a shop vac with a localized suction port right at the blade like this made from 2" PVC ..total cost Under $20.00, not including shop vac of course.
The difference is the velocity of the air moved with a shop vac is much greater than a dust collector which moves large volumes of air. This really works. :yes: My dust collector is hooked up under the saw (s) and each has a blast gate, then into 4" drain pipe, then that runs to a short 40" flex hose right to the DC.
It would work a lot better if I sealed off all the holes under the table between the cabinet. Also the slots for the tilt handle....I have the magnetic sign material, I just need to do it. The gaps underneath will require more research....spray foam? too messy. It still does a good job, but it could be better.
 

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It looks like your running (2) 4" hoses of that single trunk. Unless you have a 6" trunk line from DC through the chip collector and then to the saw, You will have problems with (2) connections on one tool. I have a 4 and a 2 on some tools and it works ok but I'm switching to a 6" trunk line myself.

What size trunk line is it? what type DC?

What size trunk line between chip collector and DC?

I agree that you need a clear hood but also one with a 2 1/2" hose fitting.
I have a 1 1/2 HP Steel City collector followed by a garbage can separator. Both are connected with 4" flex line and are placed in the next room. A 4" long sweep el brings us through the wall, followed by the blast gate. A 4" PVC Y separates the top pick up from the one under the table.
The collector has 2 4" take offs.
 

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You need a shop vac with a localized suction port right at the blade this this made from PVC ..total cost Under $20.00, not including shop vac of course.
The difference is the velocity of the air moved with a shop vac is much greater than a dust collector which moves large volumes of air. This really works. :yes: My dust collector is hooked up under the saw (s) and each has a blast gate, then into 4" drain pipe, then that runs to a short 40" flex hose right to the DC.
It would work a lot better if I sealed off all the holes under the table between the cabinet. Also the slots for the tilt handle....I have the magnetic sign material, I just need to do it. The gaps underneath will require more research....spray foam? too messy. It still does a good job, but it could be better.
Interesting! Does that little pick up you have really do a satisfactory job? Is it made to swing out of the way if I have something big to cut...IE the top of a box or something similar? I think I have the same shop vac as your red one. It is pushing 30 years old and loud.
 

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I have a 1 1/2 HP Steel City collector followed by a garbage can separator. Both are connected with 4" flex line and are placed in the next room. A 4" long sweep el brings us through the wall, followed by the blast gate. A 4" PVC Y separates the top pick up from the one under the table.
The collector has 2 4" take offs.
those (2) 4 " take offs are connected to a 6" hole on the DC. With you spitting one 4" line to (2) your starving decreasing the velocity and starving the DC.
 

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Discussion Starter #31 (Edited)
rrbrown said:
I have some new info to consider. I'm a big fan of the PVC pipe but while at a wood turning meeting at the local Machine sales company (PMC) he brought up an interesting point. Although he agrees static in PVC is not an explosion risk for the small home shop. He did say that the static build up actually works against the air flow slowing it down. I'm not sure I agree totally but It is allot more plausible then the explosion risk theory. Any thoughts?
After some research, testing, and consulting some engineer and physicist buddies I have concluded static elelectricity does build up, and in massive amounts will slow air flow. Mainly in industrial applications (systems pushing 2500+ cfm) with longer runs of pvc pipe.

The length combined with the high volume, rate of flow will decrease slightly. But as with dust explosions it is virtually non existant in small home shops.

This is purely my opinion based on my research I've done, testing in my shop explained below. I did my research on the internet with so called fact based sites not other forums (no offence to forums, they just seem like mostly opinions, such as this post), and conversation over topics with friends smarter than me :)

In my shop I charged a 10' x 6" pvc pipe conected my dustcollector to one end and hooked up a pressure gauge (harbor freight) at the other. I also used 4" at a 40' length non grounded to maximize the extreams the change was small when grounded vs not. I could not check a run of pipe longer than 40'. I figured that 40' was a sufficient length for the home shop. So I concluded that in a small shop application static electricity slows air flow nominally. But not enough to really make a difference. I will be using pvc in my shop soon. A 6" main reduced to 4" branches to my machines.

I hope this helps

-Gorilla
 

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novice dust maker
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My DC isn't working worth a crap...

I recently started setting up my little basement shop room and thought I was going to get a handle on the dust right off. I have my RAS and miter saw sitting on one wall next to each other. I ran 3" PVC behind them (approx. 6ft) with one t for hooking up the miter, then a 90* at the far end for the RAS. The other end Ls down 3ft then hooks to my homemade seperator, then my new 14 gal shop vac provides power.

I'm guessing the 2" lines coming off the main are just not enough, but I think I should still get better results. The RAS especially is just making huge amounts of dust and I can't catch it. Seems I can only get about 10% no matter how I hook it up. Ive run a single 2.5" line to the dust port ... it then spits all out the back from the blade. I ran the single line behind the saw and closed off the port ... only would suck maybe 40%. I also ran one to the port and one from the miter line to the back ... not much better.

My vac feels like it could take a finger with suction so I don't know WTH is going on. Do I need to scrap it all and start over? I need to run a vac system for now because we are probably moving I the summer and I don't want to set up a big DC until then. Would using 3 or 4" off lines from the main help. I know I need blast gates if I leave them both hooked up, but I'm ok just swapping back and forth if I need to. Any help or ideas would be soooo appreciated!



 

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novice dust maker
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Scott, if I go back and forth what would be the best way to catch both areas from the RAS? I ran the vac straight to the back but the line is too small to catch everything. If it only goes to the port it catches squat.

If I got a small wall mount dc or something would that be enough? How much cfm should I need for this small run?

Thanks for the help!
 

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Scotty D
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They make angled shrouds to go directly behind blade on RAS.

Not sure if your vac will be powerfull enough to suck with one of these tho.

Blade guard ports dont really capture much in my experience.

I wouldn't buy a small DC, you can get a decent 2HP fairly cheap, and then you will have it. :smile:
 

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With all this talk over 6 inch mains, what if your DC has 4 inch ports? Can you use a reducer by the DC to go to 6 inch and then downsize to 4 inch at each machine? Kinda seems like you should just stick to 4 inch if that's all your DC comes with.
 

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With all this talk over 6 inch mains, what if your DC has 4 inch ports? Can you use a reducer by the DC to go to 6 inch and then downsize to 4 inch at each machine? Kinda seems like you should just stick to 4 inch if that's all your DC comes with.
If your dust collector has "A" (as in one) 4" port, run 4" mains. If your dust collector has a dual 4" wye, remove the wye and run what ever sized port as your main.

Rick
 
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