I read through the thread asking about Harbor Freight dust collection. Most seemed to either have one or recommend it.

I need more info for 2 thoughts.

How do I determine how powerful the blower needs to be? 1hp, 1.5hp, 2hp...?

I don't have dedicated shop space, so I'm envisioning something that's either portable or can support hose lengths that make it wherever I am cutting.

Also, does anyone use dust collection system for fume exhaust for welding? Would a system the vents outside work well for both?

For sawdust yes?  

As with all things woodworking you should get the best tool you can afford when you need it.  I have a 2 HP in my shop but I’ll likely upgrade to an Oneida 5 HP Dust Gorilla in the next couple of years.  Hard pipe right up to each of my tools with blast gates on each line and at each tool.  

Don’t know shit about welding venting.

Separate systems for metal and for welding, don't mix the two.

I don't have a dedicated shop, I have my woodworking tools in my garage and most of them are benchtop models - but still, dust collection is a necessity unless I want a total mess in the garage.
I simply use a 2.0 HP wet/dry vacuum and connect the flex hose to whatever tool I'm using at the time.
It works fine, but the vacuum really fills fast when I'm using it on my jointer or planer!

If using a shop vac for dust collection, put a dirt devil on top of a five gallon bucket in line.  It will save a ton of bags and/or filters for the vac.

I have one built into a workbench system.  I never have dirt or dust in the vacuum.  I just empty the five gallon bucket.  I have four blast gates going to the table saw, a floor vac, a down draft table and and extra port for attaching to portable tools.

I purchased a basic Rikon single stage collector.  It works great for a single tool at a time (as was the case when I got it), but I will say that when plumbing for multiple tools or even using a surface planer the limitations become very apparent.

So without too much detail, I vote for the most powerful / largest unit you can afford and accommodate.  Outgrowing a system and needing to purchase an upgraded unit is not fun.

Get one that has a cyclone setup that drops the dust in a trashcan, much easier to unload than one that puts in in a cloth bags. Once you takeoff the bag once to empty and redo it it you will understand how frustrating that task is.

You don't want the welding fumes going through a saw dust collection system, seems to me to be a fire waiting to happen. Also welding fume hoods usually have some sort of activated carbon filter that is used to filter out the worst of the chemical fumes from flux and crud on the metal being welded.

My general advice for DCs: The HP rating of the motor does not matter for anything but being "enough" to spin the size of impeller the designer chose for the blower.

Likewise, ignore manufacturers CFM ratings.  Unless they give you their test parameters, the number doesn't mean much.   What cfm...at what restriction?

For a dust collector, the important thing for you to look for is the size of the impeller.


Mind you, unless you are willing to spend more than a couple hundred bucks, you're really shopping more for a chip collector than a fine dust collector.  Fine dust collectors need ALOT of flow.

Look into building an air cleaner to constantly cycle your workspace air.

Also, whatever consumer grade DC you get, DO replace the cloth bag on top with a big fine canister filter.  This will give that DC it's best performance with both increased flow AND finer particulate capture (pleated filter has smaller holes but alot more of them)

For welding fumes?  Inline blower or something and vent it outside.  Same as some people do with laser engravers and 3d printers