Redoing my shop DC ducting. HF 2 HP DC, is it worth it to go to 6"?

[dbhost]

I have been running my HF #97869 2HP dust collector with the Wynn canister through a side inlet Thien style separator based on a 55 gallon drum with 5" in / outlets for the last couple of years. The 5" splits to 2 4" lines, one goes to the bottom side of the tools, the other goes to the top, so that I get dust collection from say the belly pan, and blade guard of the table saw etc... at the same time.

I have a project going on presently where I am taking the sheetrock in my shop down to run power and insulate the walls, so this gives me a chance to redo the whole DC setup. Which leaves me with a few nagging questions...

#1. I do know I want to side flip the motor / impeller housing. Is it better to keep it mobile, or should I just wall mount that sucker like so many of you have?
#2. Since the output from the impeller is 5", is it even worth it to upsize the main run to 6" or should I just leave the 5" in place?

The only areas I am disappointed in my dust collection are sort of dead obvious...

#1. Lathe. I just haven't figured out how to make that work at all. It is okay for sanding, as I tend to work from the bottom side when sanding, but when cutting, it's a lost cause.
#2. Sliding Miter Saw. For two reasons. The first being it's a sliding miter saw, they are pain to collect from. The second, and most important, I don't have the proper hood built yet, I am building a new miter saw workstation with a nice hood and DC during part of this power / insulation project. So miter saw collection WILL improve. But I expect it to be far from perfect.
#3. Shop Footprint of the machine and separator. Side flipping the impeller and placing the separator immediately underneath the impeller housing will fix that and eliminate several bends, and several feet of unneeded flex line which should improve my air flow somewhat.

So what do you guys think?

Side flip, cart, or wall?
Stay with 5" or upsize to 6"?

[DarthVader]

well i built my separator with 6" in mind for future use and have a 5" reducer on atm to the stock split 5" to dual 4". im going to upgrade to 6" main trunk directly into the separator down to 4" drops. but my main trunk line is not ceiling height, it is horizontaly mounted at the sepearator height(about 3' high). Ive read this helps suction quite a bit. so i will soon know if this hurts or helps performance, however this is not an exacting test because i will be getting rid of crappy flex hose in lou of rigid pipe which is a major upgrade from what i understand. i bought my hf dc knowing i would get a bigger (which is why i am going 6" main) one in the future as i am a cabinet maker by trade and am strting to grow my business.

as far as how to mount it... mine is mobile now, i never move it. it doesnt move too easily as it is quite heavy and bulky not to mention cumbersum. i did not build a fancy 2x4 cart though with super nice casters, i just modified the hf cart. my motor is above the separator and trashcan respectively. the 2x4 cart didnt fit my space. i am now going to mount it on the wall which will help in changing the trash can and there will be no flex pipe in my new system. fingers crossed...

[Bulldog8]

Wall mount or mobile? I never moved my DC when it was on a mobile base, so I side flipped and wall mounted it. It's been that way for 1 1/2 years and I wouldn't change a thing.

Lathe dust collection? Works when sanding due to the fine dust and direction. When cutting, the tool naturally throws chips towards the operator, I don't see any way around that and still maintain visibility.

Some folks have used cfm calculators and the consensus seems to be that the 2 HP HFDC is most efficient with 5" ducting. 

[retired2]

I believe 5" plumbing is all you need for most dust collectors up to 2HP.  There may be some exceptions to that rule, but not many.  So, to help you folks that are considering spending good money and time to replace 5" pipe with 6", I did a quick little exercise to put the hoped for improvement into perspective.

I created a hypothetical system with 3 ft. of flex hose at the tool end and another 3 ft. at the DC end.  In between, I assumed a run that includes 20 ft. of straight pipe, four 90 degree ells, and one 45 degree ell.  The SP loss for that system with 5" pipe is 4.35".  If you replaced everything with 6" pipe, the SP loss drops to 4.14".  That's a 2% gain in SP.  You will never feel or see that difference.

Using the only fan curve I have, that SP gain will translate into an additional 50 CFM or less.  You might be able to see performance change of several hundred CFM, but not 50!

You probably have a different piping configuration than my hypothetical system, but I suspect running the numbers will yield pretty similar results.

There are other issues to consider.  If you only have a 5" outlet on your blower, then I'm not sure there is anything to be gained by going to 6" on the inlet side.  Also, when you go up in pipe size, FPM's drop, and if you can't maintain a velocity of at least 3500 FPM you risk having dirt settle out in your mains. 

Another word of caution.  A lot of DC manufacturers give you a "Y" that splits the nominal inlet into two smaller sizes.  That does not mean the system can handle two lines of the smaller size simultaneously.  So, two 4" lines running from a 5" DC inlet are not going to be very productive.  I doubt anyone is actually doing that, but the same comment applies if you are splitting your 5" line into two 4" lines at the machine end.

Hope this helps.
     

[dbhost]

For what it's worth, I am running the 5x4x4 splitter into 2 4" runs. It works fine, but typically for example, I only open the blast gate for the bottom of the table saw half way. It keeps the bottom half which is enclosed anyway, from building up with sawdust, and the blade guard keeps plenty clear of dust... Router table same way since the lower is enclosed. The whole idea is if I breathe it, I need more air flow. If not, I want just enough airflow to keep the machinery from getting jammed up...

[retired2]

For what it's worth, I am running the 5x4x4 splitter into 2 4" runs. It works fine, but typically for example, I only open the blast gate for the bottom of the table saw half way. It keeps the bottom half which is enclosed anyway, from building up with sawdust, and the blade guard keeps plenty clear of dust... Router table same way since the lower is enclosed. The whole idea is if I breathe it, I need more air flow. If not, I want just enough airflow to keep the machinery from getting jammed up...

Yes, the two 4" runs work because you have one choked down.  That keeps the cross sectional area of the two 4" legs close to the area of the 5" main which in turn maintains the air velocity.  Open both 4" legs and you will start to see a loss of efficiency in the waste pickup, and the type of waste will have bearing on how bad the performance suffers.

[dbhost]

Yes, the two 4" runs work because you have one choked down.  That keeps the cross sectional area of the two 4" legs close to the area of the 5" main which in turn maintains the air velocity.  Open both 4" legs and you will start to see a loss of efficiency in the waste pickup, and the type of waste will have bearing on how bad the performance suffers.

Agreed to a limited extent. I choke off the upper for certain tools, lower for others. Still messing with it overall.

But yes, it seems to work best with 5" split to a 4" on one end, and 2.5" feeding the other port...

I would bet I would probably be better off necking down closer to the main trunk line, but the fittings are a PITA to find...

[retired2]

But yes, it seems to work best with 5" split to a 4" on one end, and 2.5" feeding the other port...

I would bet I would probably be better off necking down closer to the main trunk line, but the fittings are a PITA to find...

Somewhere I posted my latest experience with catching waste from my bandsaw.  I have a 5" drop that I used in various combinations of single and split pickups.  In the end a single 4" worked better than any combination of split pickups.  I would have used the full 5", but 4" is the size of the port that I cut in the lower door.  I realize my bandsaw is quite different than a table saw, but the point is that splitting a 5" line into two smaller lines just seems to compromise both to the point where a strategically placed single line is just as efficient.

With regard to where best to neck down, I don't agree that splitting closer to the main would be better than splitting closer to the machine.  Smaller lines simply have more friction loss than larger lines, and likewise two lines will have more loss than a single line, so if you are going to split a line, keep the split legs short(close to the machine).  Now having said that, I don't think you would see much difference either way because the additional losses would be pretty small.

[DarthVader]

i found an article with actual testing on dust collectors and duct sizing etc. it shows it is not advisable to use 6" ductwork with the hf model dc. also it shows it barely meets the minimum cfm for 5" ductwork. granted these are all in stock form so any mods will definately help, i.e. wynn filter etc. its too bad hf did not use a larger impeller to take advantage of the stronger motor since these tests show it is being outperformed by smaller hp units....

http://www.portercable.com/uploads/PCD/Documents/News/182DustCollectors.pdf

[DarthVader]

also dont forget, adding the separator is lowering cfm even further....