HF Collector - What Duct Size?

[Art Mann]

If he/you didn't replace the simple sheet filter that comes with that type of vacuum with a HEPA filter, then the machine was just sucking fine dust in one hole and blowing it back out another one. Maybe that is why you had such a bad experience. The HEPA filters are designed like the Wynn filters that are often used as replacements for the HF unit but on a smaller scale.

Edit: Here is a link to the filter I have been using.

http://www.homedepot.com/p/Multi-Fit...5#.Uo7CyeJIVgg

[Stew Hagerty]

If he/you didn't replace the simple sheet filter that comes with that type of vacuum with a HEPA filter, then the machine was just sucking fine dust in one hole and blowing it back out another one. Maybe that is why you had such a bad experience. The HEPA filters are designed like the Wynn filters that are often used as replacements for the HF unit but on a smaller scale.

Edit: Here is a link to the filter I have been using.

http://www.homedepot.com/p/Multi-Fit...5#.Uo7CyeJIVgg

No, he didn't have one in it but I installed one before I started using it. I am not someone who doesn't know any better. Because of my condition, I thoroughly checked out each and every aspect of dust collection and control in my shop. I researched it all before starting anything. I tested out several ideas. Then based on my health needs, my shop layout, the tools I planned on using, and of course my budget. I believe that it doesn't make sense to spend more than you need to in order to achieve your goal. After test various DC systems, I felt that the Harbor Freight model fulfilled both my needs and my budget. I also determined that a shop vac was redundant. The HF DC did everything I needed it to do, up to and including outperforming a hepa-filtered shop vac.

[Stew Hagerty]

You know... I'm not trying to pick and fights here or to stir up some kind of huge controversy. I'm also not attempting to rewrite the laws of physics. A question was asked about using 4" piping with the HF DC. I answered that question based on my own research and experience. I then added that the HF was far more versatile in a small shop than just being used for large machines because I felt that the comment fit well within the thread's parameters. Again, that comment was also based on my own research, testing, and experience. I say that it works. I also say that if it works good enough for me, with the extensive health problems that I am burdened with, then I have no doubt whatsoever that it should work well for others.

[Ole Anderson]

The HF unit must be a real dog in comparison to the 2hp units that I've used.

Someone posted the fan curve of the HF unit recently, and from what I remember it was quite pathetic compared with an Oneida 2 hp SDG which cranks something like 800 cfm at 7" of suction. And Stew, a HF DC with 4" diameter piping is going to be a whole lot better than nothing, or just using a shop vac. I got by with a 1 hp Penn State double bagger with 10 feet of 4" flex for years and thought it did a pretty good job as a single hose collector.

[Stew Hagerty]

And Stew, a HF DC with 4" diameter piping is going to be a whole lot better than nothing, or just using a shop vac. I got by with a 1 hp Penn State double bagger with 10 feet of 4" flex for years and thought it did a pretty good job as a single hose collector.

You're right Ole, and just like you, I think mine does a pretty good job. Believe me, if it didn't collect and filter the dust effectively (Thank the Winn Filter and Cyclone), I would have a different unit in there immediately. As I've said, I cannot tolerate dust particles. Whenever it looses it's effectiveness, or out & out dies, I will more than likely upgrade to a cyclone unit such as one of these three:

http://www.pennstateind.com/store/TEMPEST.html

http://www.oneida-air.com/inventoryD...-4FE9AEFDCC1C}

http://www.grizzly.com/products/Cycl...-2-Stage/G0703

However, until then, I am quite satisfied with my trusty HF-Winn-Trash Can system. I does everything I ask of it, including collect dust from my disc sander. Plain & simple.

[Michael W. Clark]

Again, that comment was also based on my own research, testing, and experience.

How many CFM are you pulling through the branch that is connected to the sander? You are taking a huge hit with the 1-1/2" port. You may get adequate capture at the sander, but you also have to maintain velocity in the 4" duct to keep the dust entrained in the air and delivery it to the collector. You need 72"wg of SP to get 300 CFM in the 1-1/2" port and that will only give you ~3500 FPM in the 4" duct which is very marginal.

I have a 1.5HP Jet and tried connecting it to a ROS (1-1/4" port) and it did basically nothing. I have also tried it with mulitple 4" gates open and found it lacking. I am upgrading it to all 6" and 5" duct with appropriately sized connections at the machines. I have a small shop and no room to really wheel it around with a hose connected. It is better for me to have short runs of hard pipe and a stationary system, less overall SP loss and therefore more CFM from the fan.

Mike

[Stew Hagerty]

How many CFM are you pulling through the branch that is connected to the sander? You are taking a huge hit with the 1-1/2" port. You may get adequate capture at the sander, but you also have to maintain velocity in the 4" duct to keep the dust entrained in the air and delivery it to the collector. You need 72"wg of SP to get 300 CFM in the 1-1/2" port and that will only give you ~3500 FPM in the 4" duct which is very marginal.

I have a 1.5HP Jet and tried connecting it to a ROS (1-1/4" port) and it did basically nothing. I have also tried it with mulitple 4" gates open and found it lacking. I am upgrading it to all 6" and 5" duct with appropriately sized connections at the machines. I have a small shop and no room to really wheel it around with a hose connected. It is better for me to have short runs of hard pipe and a stationary system, less overall SP loss and therefore more CFM from the fan.

Mike

Wow, Mike that was a whole lot of numbers and stuff.
Perhaps I didn't explain myself well enough.

My system works!

My medical condition makes me hyper-sensitive to dust.

I am not bothered one iota by dust in my workshop.

That includes not only when I operate my machines, but also when I use my handheld power tools .

That includes my disc sander.

My system works.

And if I am not bothered by the dust I generate then it should work fine for others as well.

My system works.

[Michael W. Clark]

I'm glad it works for you Stew. I would add a port on the 4" duct to bleed some air in. This will keep the 4" duct swept clean and minimize the risk of material build up in the duct.

Just thought you might have had some numbers from your research and testing.

[Stew Hagerty]

I'm glad it works for you Stew. I would add a port on the 4" duct to bleed some air in. This will keep the 4" duct swept clean and minimize the risk of material build up in the duct.

Just thought you might have had some numbers from your research and testing.

My testing was practical rather than scientific.

As for the "duct", it is a length of 1 1/2" hose connected to a long 4" Dust Right expandable hose attached to a blast gate that leads, via a short flexible hose to the trash can cyclone. I've been using this same length of 4" Dust Right hose for 2 years now and the only thing that has ever built up in it was shavings from when I try to vacuum up too large of a pile of handplane shavings all at once.

[Greg Peterson]

My testing was practical rather than scientific.

I'm not challenging your experiences, I'm just not willing to be a canary in the coal mine. I use a particle counter to show me precisely how clear the air in my shop is.

I have a Delta down draft sanding table that I connect to the DC (Wynn cartridge filter and Thein baffle). I also connect the shop vac (with Dust Deputy and hepa filter) to the ROS. I wear a respirator during sanding operations, based on the particle count I am getting. Obviously our experiences differ. I wish you continued health and success with your configuration.

[Michael W. Clark]

Stew, I was genuinely interested in your numbers and research. I imagine you did your due diligence given your situation. There are several of us DC geeks on here that like to see numbers because we know the mfg numbers are a stretch at best.

I'm glad your system is meeting your expectations.

[Art Mann]

I just repeated the experiment tonight that I did a few years ago and got the same results. I hooked up my Delta 50-760 through a short length of flex hose, an 8 foot length of 4 inch galvanized pipe, an adapter and about 6 feet of vacuum hose. I bypassed the separator to get maximum suction. It worked okay but I repeated the same experiment with my 10 amp Genie shop vacuum and the suction was noticeably stronger. This experiment isn't hard to do. Since there is some difference in experiences here, I would suggest that anyone who is contemplating both methods to try both and use the one works best for them.