Optimum diameter?

[retired2]

Phil, I've searched the forum for threads discussing separator diameter, and was not able to find much specific guidance on minimum or maximum size, probably because most people simply let their container determine the diameter.

I have a Delta 50-760 and I plan to build a top hat design with 5" inlet and 5" outlet".  I might build a rectangular inlet based on the previous discussion we had.  I currently have a Brute 20 gal plastic garbage that I plan to use with the separator.  The inside diameter is 17-7/8".

My first thought was to mount the top hat right against the underside of the DC.  However, I quickly discovered that would limit my separator diameter to 16", or possibly less, due to the adjacent flange on the chip bag.

If I drop the separator down, I can build it with a diameter of about 17"(to match the 20 gal Brute).  That's not a great deal larger, but to go bigger I would need a 30 gal can.

So, the question is, based on your experience and testing, what comments or suggestions can you make on diameter?

[phil (admin)]

So, the question is, based on your experience and testing, what comments or suggestions can you make on diameter?

Typically, the smaller the D, the faster the rotation and the better the separation, but also the greater the loss due to resistance.

How do you like that answer?

Things are further complicated with getting the fittings, well, fit.  Smaller diameter units would be easier to accommodate with top hat designs because you're typically going to use a side inlet.

But you can get the diameter so small that the inlet is basically feeding the outlet and you get little rotation.

16" and even 17" are pretty small for 5" pipes.  If it were a typical cyclone, you'd get great separation.  But in one of my designs, I think you might get some short circuiting (where incoming debris goes right to the exit port).

[retired2]

So, the question is, based on your experience and testing, what comments or suggestions can you make on diameter?

16" and even 17" are pretty small for 5" pipes.  If it were a typical cyclone, you'd get great separation.  But in one of my designs, I think you might get some short circuiting (where incoming debris goes right to the exit port).

Thanks Phil, you're answers are helpful even though different answers would have made my task a little easier.

Two changes I plan to make:

1) I have been debating about ditching the Delta 50-760 wheeled cart - it imposes too many design and construction limitations, and my DC will be stationary anyway.  By building my own support, I will have more freedom on the sizing of the separator.

2) I will replace my 20 gal garbage can with one that has a larger top diameter.  I hope a 30 gal can is large enough because I don't want to handle the weight of something larger.

Thanks again.   

[WayTooLate]

Retired -
The size of the waste can is more a function of convenience rather than performance... 

It depends on what you expect your usage to be. 
On my shapers which run for several hours each day, I have 20 or 26 gallon 'Brutes'.  Some get dumped once, some twice each day.  The generate a lot of waste and I want the small can to get dumped regularly. 

I have a cut-off saw that gets minimal, infrequent use.  I have a 55 gallon drum for it because nobody wants to spend 10 minutes emptying it when they only made two cuts.  So we avoid it for as long as possible... 

In a production environment, I want it to be either so easy and convenient that it happens without interrupting the workflow, or, I want to postpone it as long as possible. 

For a hobbyist, I think it depends on one's personality.  At one extreme, a neat-freak can use smaller containers because they will get dumped after every task - or at least daily.    At the other extreme, a procrastinator will want large containers.  Out-of-site, out-of-mind until it is absolutely necessary.   

Before building a separator, were you inclined to keep you shop neat and clean after every project?  Or, were someone you just wanted the debris out of your way so you could get your work done?  NO moral judgement here - both extremes produce work to be proud of.  Most of us are somewhere in between - this will just give you an idea of how you will actually use your separator and what the 'dump-cycle' will likely be. 

Hope this helps!
Jim

[retired2]

Retired -
The size of the waste can is more a function of convenience rather than performance... 

It depends on what you expect your usage to be. 
On my shapers which run for several hours each day, I have 20 or 26 gallon 'Brutes'.  Some get dumped once, some twice each day.  The generate a lot of waste and I want the small can to get dumped regularly. 

I have a cut-off saw that gets minimal, infrequent use.  I have a 55 gallon drum for it because nobody wants to spend 10 minutes emptying it when they only made two cuts.  So we avoid it for as long as possible... 

In a production environment, I want it to be either so easy and convenient that it happens without interrupting the workflow, or, I want to postpone it as long as possible. 

For a hobbyist, I think it depends on one's personality.  At one extreme, a neat-freak can use smaller containers because they will get dumped after every task - or at least daily.    At the other extreme, a procrastinator will want large containers.  Out-of-site, out-of-mind until it is absolutely necessary.   

Before building a separator, were you inclined to keep you shop neat and clean after every project?  Or, were someone you just wanted the debris out of your way so you could get your work done?  NO moral judgement here - both extremes produce work to be proud of.  Most of us are somewhere in between - this will just give you an idea of how you will actually use your separator and what the 'dump-cycle' will likely be. 

Hope this helps!
Jim

Jim, 

Sounds like you have multiple separators, each located at the tool.  I'm just a hobbyist, so I will have a single separator located at the DC. 

Personality wise, I am probably closer to the neat-nik.  However, when I'm in the middle of something, it gets pretty messy before I take the time to clean up.  However, when I know I'm done producing heavy dirt, I clean up thoroughly - don't want the dirt throughout the house.

Regarding size, I don't generate huge amounts of waste.  Thickness planer is the worst, and I used to buy all my wood rough and plane it myself.  I don't to much of that anymore.  So, depending on what I'm doing I might have to empty the container daily, but the norm might be more like weekly.  The 20gal would be convenient for handling and keeping the separator a little smaller, but I assume you saw Phil's comments about the diameter of that size separator possibly being a little too small for a 5" system.  So, I'll probably go to the 33 gal can in spite of the fact there are more issues for me with that size.

Thanks

[Rick T]

One thing about the separator is that it allows you to (almost) fill your collection container to the bottom plate of the separator whereas with the traditional bag on a DC when it's 2/3 to 3/4 full, it starts to give up it's contents into the filter. One advantage of the 'top hat' design is that you get almost the full capacity of the collection container but with the designs with the baffle in the container, you may loose @ 1/4 of the capacity of the container which is significant for a 20 gallon size.
My container is 33 gallons I presume.. just an old Rubbermade garbage can I had kicking around unused for 20 years. When it is filled to the top with dust, I figure that's enough weight and bulk for me to be handling.

[WayTooLate]

Rick -
You are right!  33 gallons of sawdust too much heft to dump.  ...I guess that is why I try to keep my teenage sons around for 'chores'! 

My first 'Rubbermaid Separator' was a 33 gal Baffle-Inside-Design.  I even used the lid - just added backing plates for the inlet & outlet fittings.  The baffle sits down on the ledge at the handle height.  It works quite well - especially as my first attempt. 

However, the reduced interior volume is not a real problem - it keeps it from getting too heavy to dump.  The real issue is the lid has to be raised up several inches to clear the can.  Since I wanted a short run of hose to the DC, it was a real pain to flex it up and out of the way.  Top Hat designs only have to be raised high enough to break the sela and clear the lip - a huge advantage! 

Hope this helps!
Jim

[Rick T]

re: Fine dust capture ratio.
I got the bright idea to replace a piece of concrete floor in the basement woodworking shop. There was a large old concrete pad that supported the 'octopus furnace' many years ago.. un-level, porous, didn't match level of surrounding floor and so forth. At any rate I decided to take the top off the @ 6" thick pad and re-pour the top to match the surrounding floor. This involved scoring the pad @ 3" deep and chipping it off in 2" cubes with a chisel and hammer. That's @ 200 lineal ft of cutting with a diamond blade in my circular saw. Dust!!! Well I opened a few windows,  started a large fan, my ambient air cleaner and stuck the hose from my DC behind the saw blade in hopes of getting some dust close to source.
We are talking fine concrete dust here. The separator did a pretty good job I think. When I was finished, I had @ 6 gallons of dust in the garbage pail. @ 4 cups of very fine dust had by-passed and was lodged in the filter and almost nothing in the collection bag. That's a capture rate of about 85%, and we are talking all very fine dust here. Pretty impressive.
A couple of woodworking friends are visiting my shop today to have a look at the separator and DC setup. I expect we will be into a group build shortly. ;D ;D 

[phil (admin)]

The separator did a pretty good job I think. When I was finished, I had @ 6 gallons of dust in the garbage pail. @ 4 cups of very fine dust had by-passed and was lodged in the filter and almost nothing in the collection bag. That's a capture rate of about 85%, and we are talking all very fine dust here. Pretty impressive.

I recently pulled-up old tiles on my shop's floor.  This left the yellow glue behind.  I tried everything chemical-wise to remove the stuff, it didn't budge.

I finally decided to use a diamond wheel to grind it off.  I got one of the Bosch angle grinders that comes w/ the diamond wheel and connected this to my separator/shop vac combination.

The separator worked pretty well, but I will say that super-fine concrete dust mixed w/ the yellow tile glue is a challenge.  The diamond wheel sort of reactivates the glue, and the resulting dust sticks to surfaces.  So dumping it out of the separator is even a pain in the you know what.

The separator got about 90% of it.  What did make it to the shop vac went right through the drywall bag I had in there and into the filter.  It was amazing.  When I took the top off the shop vac it started coming out almost like smoke.

It took at least a couple of hours to clean everything up after that project.  Even blowing the sticky dust with the air compressor outside didn't remove it, I had to brush it off w/ an old paint brush and blast w/ the compressor.

I am soooo happy that project is over.

[Rick T]

Well Phil, sounds like our projects and results were very similar and the unit is a marvel. Today my 2 friends and I did some testing with different hose combinations both dia and length. I think we were all impressed with the excellent results, whether coarse chips off the planner or fine dust off the oscillating spindle sander, it handled them all.. zero dust added to the collection bag in the process. I think they are going to arrange a group build as a result. Thanks for the concept and also to all those who contributed the incremental improvements.