I’ve been doing a lot of investigation, research, and pondering about my new dust collector, so I figured I’d track my thoughts in the blog to hopefully save people time who are doing the same, and also to show how I ended up setting up and how I got there.
I picked up a Jet 1100a dust collector on Craig’s List for $175, with a bucket of blast gates, hose claps, and reducers tossed in to round it out at $200 (and the bucket… never can have too many of those). It is in great shape (hardly used)—the seller was moving into a smaller place and didn’t have the room for his shop anymore.
I hooked it up and wanted to test it out (stopped by Woodcraft on the way home with it in the car to grab 10’ of flex tube to get started). While rolling it around the shop is okay given the casters, it became obvious that fixed ducts were definitely the way to go. I naively thought I’d just look online to see how to set that up…
Metal v. PVC.
Grounding and explosions.
Static pressure math.
Internal friction per lineal foot.
Elbow to straight pipe pressure conversion tables.
Wow. And I just wanted a clean shop and clear lungs!
To make a (very) long story short, I measured the runs, angles, wyes, etc. that I would need to reach my machines and do so in a way that minimized distances and angles, as well as keeping the ducts out of my way.
I was figuring I should use 6” duct for the main. I put together a spreadsheet where I added up the static pressures, and discovered that I was nowhere NEAR the static pressure limit (only about 50%) even when using 4”, so that will save me a lot of money, bulk, etc. Glad I did that analysis. Any my shop space doesn’t have much space left, so it’s not like I might override the limit eventually even if I did add more machines or wyes.
FYI, I used a combination of the items linked here to figure it out. Very helpful information here.
So then the next question comes: Metal of PVC. Wow. Talk about a loaded question…A summary of my decision to go with PVC:
- I priced out PVC v. Metal and the metal solution was over 2x as expensive. The straight portions were more but not terrible, but the wyes and elbows really were killers.
- PVC installation is easy—cut to length with a saw, glue it up. Done. I’ve run ducts before and the snapping together and cutting the edges with tin snips, etc—all just ends up being rough and literally painful
- I can get every imaginable piece I need at Home Depot. To do the metal I’d need to mail order some parts and pay shipping for large items that can’t be flattened
- After researching the static electricity explosion issue, it seems there is a lot of “just because it hasn’t happened” warnings out there from people who are not experts. But there are also studies done that a home system in a small shop has little to no risk of explosion, and that a grounding system (in and out of the pipe) can mitigate that even more.
If this were my end-all, custom-built, I’m-gonna-retire-here shop, I’d go metal all the way. But being that I’m evolving and not sure what my shop will need to be, I’d rather have something cheaper and more malleable to start with. I’m going to ground the crap out of it to be safe and get back to my woodworking.
I’ll continue the series soon with system assembly. I’m going to go buy all the elbows and wyes that I need and position them where they need to go so I can measure for how much straight pipe I need to buy, and in what lengths.
-- Todd (Denver, CO -- Highlands)