PVC Pipe and a DC System

[TEF]

I know that a lot of you have utilized white 4" PVC pipe in their workshop Dust Collection systems. I am thinking about doing the same in order provide multiple inputs around my shop for a 2 HP DC. However, I note that when buying the 4" PVC that measurement denotes the inside diameter, while standard WW DC hardware (blast gates and other connections) measure 4" as the outside diameter. If I were to integrate the PVC with standard WW flexible hose and other fittings, how does one make the mechanical connections between the two sets of materials? Does one just jam the WW parts into the PVC? Are there adapters in the plumbing world that could be used to transition between the two systems?

Thanks in advance for your advice.

TEF

[Bob]

Quick advice tips:

1. Dust collection fittings sold in Woodworking stores are grossly overpriced. But you may need some of them anyway.
2. Buy your hose clamps at Lowe's or Home Depot. They are cheaper and better.
3. Be sure to use S&D pipe (Sewer and Drain), not Schedule 40 pipe. The latter is about 2-3 times the price.

I use a woodworking fitting called a splice fitting to adapt to flex hose. Its overpriced but the convenience is worth it, I guess. These are available in various incarnations. Here's a link to one

make slits in the PVC pipe to allow it to clamp down on the splice tightly. I'll post some pics in alt.binaries.pictures.woodworking.

Bob

[max]

If any one uses plastic pipe for their dust collector you have to make sure to ground it or it can explode. Plastic is an insulator and the friction of the dust moving through it can cause a static buildup and then an explosion. There are many documented incidents of this happening. I run a bare metal wire through all of the pipe and attach it to the dust collector housing and the tool housing to pick up the static discharge, This is a serious issue. max

[Mike in Mystic]

If you can point us to a documented incident of an explosion happening in a small-shop environment from a dust collection system using plactic conduit, you would be the first. Contrary to what you're saying, this is NOT a realistic risk. This has been reported in Fine Woodworking and other woodworking magazines. Using a ground wire is necessary only to avoid build-up of static charge on the pipe. The worst that will happen is you'll get a mild shock. The REAL danger is in the location where the dust is stored. If you allow metal objects to enter the system and hit the impellor or your dust collector, a spark could ignite the stored dust and start a fire (not an explosion).

Explosions from dust happen in things like grain silos, not in home shop dust collection systems.

Here is a very good link to an article covering the subject at great length:

IS a serious issue. SERIOUSLY miscommunicated.

Mike

[Edwin Pawlowski]

No one has yet to post one. Please do so or stop spreading false information.

[Ba r r y]

Here we go...

Barry

[Ace]

Mike that article you recommend

't come up. Is there another place to view it?

.shtml

[max]

I can't remember the sources for this but it was heavily discussed in Fine Woodworking and other periodicals in the 80,s and early 90's. I did remember a couple of shop owners responded to the discussions that this had happened to them. Adding a grounding wire through the pipes is cheap insurance to possibly prevent an explosion or even just a fire. I am sure Oneida can ad to this discussion if any one from that company is in this group. I am not trying to scare or mislead. The information I had access to at the time was pretty convincing. max

[Mapdude]

you missed the wrap on the url:

[loutent]

I "agonized" over the debate about PVC & dust explosions about 5 years ago when I installed my system. I concluded that it it a simple matter to ground the whole thing & the cost was insignificant (maybe $10).

Also, I used the S&D pipe mentioned and wrapped the joints with a few turns of duct tape in order to get a snug fit. Clamps cinched them up fine. So far, this has worked very well with no problems except I have to clean out the blast gates once in a while (bought the plastic ones).

To ground the system, I drilled a tiny hole at each joint, threaded the wire through the pipe length, then use a lead (or whatever they are these days) split shot to hold the wire taught against the pipe.

Lou

[Greg]

Hey, I have a ceramic snake in the yard to keep the tigers away and it works great. Never saw one. ;-) If it makes people feel better to have a bonding wire in their pipe why criticize them? While you are at it go ahead and bond all of the metal parts of the system that may become energized by other voltages. Nobody can call that a bad idea. This might be important if you have switchesm actuators and such around the system.

[Scott Lurndal]

I don't suppose you can cite any of the documented incidents?

scott

[Michael Baglio]

For the official rec.woodworking fix on pvc dust collection explosions, get some silly putty, a pair of pantyhose, some #10 rubber bands and read this:

Problem solved. And like the post said, please post pictures.

Michael

[Bob]

That's an urban legend that's officially classified as rec.woodworking tired topic #33.

Nobody's ever had an explosion in a home dust collection system due to static electricity.

Bob

[Bob]

As promised I posted some pictures in alt.binaries.pictures.woodworking.

Bob Davis Houston, Texas

[Rob Stokes]

Oh, stop with the exploding PVC dust collection systems Max. It's a myth. Is it possible? Yes. But the circumstances would have to be such that a million other things in the shop would have caused a sawdust bomb long before a PVC DC system would.

There are no (as in not one) documented incident of this happening. the closest thing on record is a grain elevator explosion. Grounding is always good... Metal is better, but PVC is just fine. It's not a serious issue. In fact, it's not an issue at all.

Rob

[patriarch]

Michael Baglio wrote in news: [e-mail]:

This makes as much sense as anything else I've read here. I mean, if they won't believe the PhD over on Woodcentral/Badger Pond, then who will they believe.

Patriarch, who prefers this religious discussion to the political diatribe.

[Mike Hide]

I have reduced the static problem to a virtual asset.

I have lined each section with copper wires , connected all the wires in series to a high speed rotational switch. the switch in turn is conected to an ac converter which is then connected to the dust collection main drive motor.

So what I have ended up with is a self powered dust collection system , in short a perpetual motion machine .As you can imagine my shop is absolutely spotless. At times when I am not using the DC system I just divert power to the household circuit breaker box . Since I discoved this phenomenon my whole local community has taken advantage of it and bought dustcollecton systems even though most don't have shops .

The only major problem so far is we have not found a way to turn the dam things off,so everyones lights are on 24 hours a day and frankly the noise of all these machines running night and day is driving us berserk...mjh

[TEF]

Bob,

Thanks for posting a photo of the required adapter piece. As a matter of fact, I have one of those and will get more when I start the PVC project. Oddly, the part you show in the picture has shoulders on each end for clamping hose or inserting into the PVC. However, the plastic Delta blast gate that I have seems to have tapered shoulders on both sides making them more difficult to firmly clamp hose or insert into the PVC. I just don't understand the design of the gates and how they're intended to be incorporated in a DC system. Even if one used just WW parts and hoses (never mind the PVC pipe), I can't understand why blast gates would have tapered connections on both ends.

Thanks again.

[Ba r r y]

Two years later, I got tired of clogs related to the wires and pulled them all out. Other than the lack of clogs, I see no difference. Dust dosen't stick differently to the pipe, I don't get shocks, etc... My tools and the DC are still grounded via the AC ground.

I'd be much more concerned about fumes from finishing products and adhesives, and glowing steel from belt sanding tools as a fire hazard than dust.

Barry