Dust collector decisions

[Cdlong]

I may have a craigslist problem. I now have two dust collectors, not counting my original shop vac/dust deputy setup. Both seemed like too good of a deal to pass up so here we are. The two systems are rather different and I want to mix and match and sell the rest.

First one is a Jet 1.5 HP 1100cfm https://www.rockler.com/jet-vortex-d...p-w-bag-filter but was modified to be wall mount and discharge outside so the whole cyclone/bag/filter part is gone, it has a 6" inlet and 5" outlet. Plus a super dust deputy with a 5" inlet and 6" outlet, 30ish gallon bucket, a bunch of 4", 5", and 6" metal ductwork and fittings, and flexible ductwork. $150 total.
It's bigger than I wanted and I'd rather not suck all the heat out of my garage, but I wanted a full size dust deputy and the other stuff doesn't hurt.

The second one is an older version of the Rockler 3/4 hp wall mounted unit, https://www.rockler.com/dust-right-r...lector-650-cfm this but with a different paint job. It has a 4" inlet and 5" outlet. Just the bag filter (it fits on both) so not great filtration, but I doesn't suck all the air out of the shop. $100.

I originally wanted the 3/4 hp unit because I thought it'd be a bit quieter (it's not, they're basically the same), and I was planning on just a 4" duct system with a dust deputy. Pretty small shop and smaller tools, none of them have a 4" port, only one tool at a time, and currently no jointer or planer or big chip producers. Also, the 3/4 hp would use less power and I have a pretty poor electrical setup in the garage. Currently the shop vac and Sawstop JSS pro will trip the one breaker I have access to at the moment.

So would it work to have 4" ductwork, transition to 5" for the dust deputy, 6" out transitioning to 4" into the Rockler 3/4 hp fan into the bag, eventually upgrading to the HEPA canister filter. Bad idea? Should I just keep the whole 1 1/2 hp setup and get rid of the 3/4 hp unit.

[drzaius]

Filtration is the better way to go if you're concerned about blowing all the heated air outside.

Lots of air is needed for good dust collection and you may find out that even the larger one doesn't have the jam to do a good job of it.

[William R]

This is a hard subject and a touchy one at the same time. Everyone has their own best opinions. If you’re going down the road of dust collecting for present and future. Then if you haven’t then visit this site the man has done a lifetime of research and has posted it on his website. If you come away confused don’t feel bad theirs is lots to learn and consider. 
https://billpentz.com/woodworking/cyclone/index.php

[drzaius]

The Pentz site is a bit of a rabbit hole, but well worth spending some time on. 

[gee-dub]

I agree with drzaius on the 1.5 being on the small side.  I think that the smaller Rockler unit will be adequate only for the most minor collection tasks.  Maybe as a single machine dedicated unit? 

Even a really good bag is more of a fine dust spreader than a filter.  The 1.5HP is designed as a bagger and adding separators to these come with various levels of success.  You are correct that you really want a separator.  I did nothing but struggle until I made the move to a two stage system many years ago.

You talk of heating your shop so you live where there is actual weather.  I am afraid the literal bliss of being able to vent outside may not be your best solution.  Good separation, good filtration, and an adequate blower to maintain the air speed of the air volume required is your balancing act.

According to Oneida the SDD will work with system from 350CFM up.  I find this startlingly optimistic but they definitely know what they are doing.  If you want to cherry pick from what you have and not dive too much deeper into things I would:

Get a good .3 micron filter with adequate surface area for the CFM of your blower (650CFM advertised).

Rig the filter up at the blower's outlet.

Add the SDD as close as possible to the blower's inlet.

Make your waste bin easy to empty.

Run your ducting with as few twists and turns as humanly possible.

When I built my new shop I planned to upgrade to a 5HP cyclone.  I also did ump-tillion revisions of my duct layout to make them as short and direct at possible.  I installed my old 2HP cyclone and it has done a good enough job that I have held off on the 5HP upgrade for a couple of years now.  I am rattling on about this to point out that you can get better than expected service out of something if you really tailor the design.  Time well spent.

[Cdlong]

Thanks for the responses. It seems the 1 1/2 hp unit is the way to go. I have seen the Bill Pentz site but haven't read through it all yet. Maybe I shouldn't admit this, but I am an HVAC engineer so I'm already pretty well versed in many of these concepts, just not about the wood chip and dust part. I already have my own opinions and pet peeves (namely fan system effects that are often royally screwed up).