DC Setup - PVC Sch 20 vs. Sch 40

[lago]

FWIS...I picked up the HFDC last December and have been working on setting up my DC system since then. Picked up all of the parts at a local Ace Lumber & Hardware(better prices and inventory than BORG or Lowes).

Went back last week to pick up some more S&D pipe and 45 degree fittings. Got home and noticed that they were different then the original ones I had gotten. For lack of a better description, these had a male & femal connection. If you wanted to use 2 to make a 90degree angle, you didn't have to have a short piece of pipe between them.

Ken

[Texas splinter]

I think that those fittings (male on one end, female on the other) are called "Street Elbows".

[mikel]

I would love to see pics of what people have done. I just got a used grizzly DC and am looking to see the best way to get it working for me...

thanks...m

[LCHIEN]

I think that those fittings (male on one end, female on the other) are called "Street Elbows".

Yep:


Elbows (ells) change direction of pipe. Most common are 90o and 45o elbows, but are also available in 22 ½ and 60. They are identified by their angle but they are ordinarily referred to by number only. An ell may be female at both ends, or in the case of a street ell, may be male on one end and female on the other. Some are offered in a long-turn variety, some have side inlets; some have vent inlets.

from
http://www.keidel.com/mech/pvf/ftg-intro.htm

[WoodButcher26]

"It's been sort of a urban legend that static will cause a dust explosion with woodworking dust collectors. Static can be a irritating thing, you can just ground your tools, which they should be anyway."

Loring, you're saying that you really don't need the grounding wire wrapped around the PVC? Since starting to put together my setup, I've looked at a dozen or more deisgn suggestions both online and print, and all of them advocate grounding your plastic tubing system.

I'm using schedule 20 pipe from Lowe's, standard pipe and fittings. All of my tools are grounded, but I haven't even turned on the collector yet and noticing static electricity buildup in the pipe. Somehow I think that I'm going to need something other than just the tools grounded, but I'm willing to keep an open mind.


Kim

[LCHIEN]

"It's been sort of a urban legend that static will cause a dust explosion with woodworking dust collectors. Static can be a irritating thing, you can just ground your tools, which they should be anyway."

Loring, you're saying that you really don't need the grounding wire wrapped around the PVC? Since starting to put together my setup, I've looked at a dozen or more deisgn suggestions both online and print, and all of them advocate grounding your plastic tubing system.

I'm using schedule 20 pipe from Lowe's, standard pipe and fittings. All of my tools are grounded, but I haven't even turned on the collector yet and noticing static electricity buildup in the pipe. Somehow I think that I'm going to need something other than just the tools grounded, but I'm willing to keep an open mind.


Kim

I think its been debunked in general but the program Mythbusters recently had a thing where they proved you could not explode a sandblasting system blowing a lot of sand through a plastic pipe which is very similar. The chief reason it will not explode is that you just cannot have a high enough concentration of dust in woodworking to sustain an explosion.

You can have static buildup for sure, and possibly a spark, but its not dangerous from an explosion standpoint since the dust density is so low. The static will build up on the plastic pipe but the total charge stored is also small (because plastic is a non conductor) and therefore fairly harmless from a shock point (very mild) of view. Now if the pipe were plastic but had ungrounded foil wrapped around the outside and theinside then you could get a big, possibly uncomfortable, shock because now you've built a big capacitor.

If you have grounded foil or wire wrapped closely around the outside then you would have no static build up at all because it would have a bleed off path.

[WoodButcher26]

Yeah, I heard about the Mythbusters thing, and I discounted it for one very important reason--sand is not combustible. Wood dust IS very combustible, and flammable, ask any one of the big cabinet shops. My next door neighbor used to live across the street from a Lane cedar chest shop, said they had a dust collector explosion about once a month.

As for static electricity: Having worked with it for years in electronics, it's very easy for a static charge to have tens of thousands of volts. Yes, you heard right, tens of thousands. The amperage is very low, usually a few millamps, but with that much voltage you can still have a spark that will set off anything flammable nearby. Ask the guys who have had fires filling gas cans sitting on the plastic bedliners of their pickup trucks. And no, that is not an urban legend as I have heard elsewhere.

Sorry Loring, I'm still going with the expert's recommendations of grounding my pvc system, better safe than sorry.


Kim

[wardprobst]

Yeah, I heard about the Mythbusters thing, and I discounted it for one very important reason--sand is not combustible. Wood dust IS very combustible, and flammable, ask any one of the big cabinet shops. My next door neighbor used to live across the street from a Lane cedar chest shop, said they had a dust collector explosion about once a month.

As for static electricity: Having worked with it for years in electronics, it's very easy for a static charge to have tens of thousands of volts. Yes, you heard right, tens of thousands. The amperage is very low, usually a few millamps, but with that much voltage you can still have a spark that will set off anything flammable nearby. Ask the guys who have had fires filling gas cans sitting on the plastic bedliners of their pickup trucks. And no, that is not an urban legend as I have heard elsewhere.

Sorry Loring, I'm still going with the expert's recommendations of grounding my pvc system, better safe than sorry.


Kim

Fine Woodworking 153 has an article on the small risk of explosion with 4" PVC pipe in a home system of less than 3HP. Pretty minimal- where it does get risky is in larger systems with bigger ducting and lots of cfm going by. All that said, I went with a metal duct system because it's safer and made for the job. Like anybody, I like to save money but safety is the last place I'll try to save a buck.
YMMV,
DP