Okay – I searched the archives for a while because I know this has been beaten to death, but I wasn’t finding what I was looking for.
I am trying to decide what material to use for the piping and fittings for my dc system. I’ve heard talk about snap together hvac, pvc, spiral galvanized, flex hose, etc. I’ve also heard that I should go with larger pipe than 4″. What I would really like to do is install a 6″ spiral galv trunk line with 4″ laterals and gates to my machines. I can get the materials for this from my local shop, but it’s ungodly expensive. The laterals are over $50 each.
For much less money I could go with 4″ pvc, but just don’t know if this will be as good.
In case you’re wondering, I have a Jet 1100 dc. I have 4″ ports already on a planer, table saw, band saw and router table and would like to be able to collect from a few other smaller tools. My shop is in the basement and my power tools are all along one wall, probably about 30 feet long. My plan was to position the dc at one end of the line of tools with the trunk line running down the wall on the floor with laterals feeding the tools.
Thanks for your comments.
Replies
I have been planning for a dust collector for a while and found the following two books very helpful in figuring out the details you are working on. "Controlling dust in the Workshop," by Rick Peters, and "Workshop Dust Control" by Nagyszalanczy. Both cover the basics and give general design criteria. Also, in a past issue of FWW there was a very good article on PVC as the plumbing for dc. Basically said not an explosion hazard if grounded. From my research it appears that the major differance is as follows:
PVC generally has smaller radius elbows, that adds friction to the airflow and reduces overall effectiveness than metal pipe specifically designed for dc work. This is also true for heating system pipe from the local hardware. Given a relatively low CFM in the dc, you need all the air & suction possible at the tool. Thus, a trunk line of 6", then branches of 4"; with wide radius curves, and wye instead of 'T' intersections. Good luck.
When I moved in a few years ago, I put in the DC in a hurry because "this old house" needed my attention, not this new shop. I used the ribbed black drain pipe (ADS?) and it worked sort of OK (for 11 years). It had lots of turbulence (read: friction, slows air flow) and would shriek when the air flow was high. I never grounded it, it never exploded.
I've just moved the DC outside and put it into a new shed addition to the garage with the air compressor. I replumbed with co-extruded drain pipe and used the proper fittings. I used "Y"s and made all 90 degree bends with paired 45's. The co-ex pipe is a thick polyethylene pipe (read unglueable) with a thin PVC annular layer (on the outside). The PVC glues. It's cheap, available, and very impact resistant (PVC can be a little brittle).
Ground or not ground? Ground inside or outside? Search the net and find devoted adherents to every opinion. I've not grounded my new (or old) system, but may ground parts of it if I get zapped.
One VERY IMPORTANT piece of advice, learned the hard way: Put some type of collection vessel (like a cyclone) between the piping and the dust collector. My Grizzley came to a frozen halt with a small chunk of plywood between the impeller (fan) and its housing. Lots of disassembly fixed it, but the shaft is slightly bent and squeeks as it slows to a stop. I'm sure I shortened its life some. My cyclone is a 30 gallon drum with two angled inlets on the periphery of the top and the outlet (to the DC) in the center. The one for the metal trash cans looks pretty good, but you can make about anything your self if you want (and cheaper).
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