6" Pipe Installation

S

sreilly24590

New member
So I have my CV1800 installed 90% of the way with a few ports capped due to not being ready quite yet. I have a drop with a wye for two accesses, one for the drill press and one for the lathe (Shopsmith) which will basically be hoods on stands. Then I have one more drop with a wye that will service a miter station with hood once built and an additional connection for either the SuperMax 19-38 or the 13" planner depending on need. I do have one 6" drop that serves both now as needed with a 6" to 4" adapter. The adapter I have is not very good I'm afraid as it should probably be more like a cone with 6" tapering down to 4" but instead is like a 6" can with a 4" collar cut into it if you can imagine that. At this point I have the 6" PVC taped together using 3" wide aluminium tape which is fine for the horizontal parts but less than adequate for the drops (vertical). The PVC is supported by using a mesh nylon 2" wide strapping material which is secured to the ceiling joists thus eliminating vibration. It's the same method used to hang metal HVAC ducting in crawl spaces.

So at this point I'm thinking I need to either seal the vertical pieces with caulk or drive a screw or two into the PVC. I noticed a previous past post that mentioned using self tapping sheet metal screws and really think this isn't the best choice. I don't think, and could easily be wrong, but I would suggest not penetrating the inner wall of the PVC. Instead I would think drilling a pilot hole and using a screw that will go through the outer pipe/connector and then into but not penetrating the inner wall of the connected piece might be better. Maybe this is overthinking this but by not penetrating the inner wall doesn't disturb the air flow at all.

Ideas, suggestions? KNow of a better way to secure the vertical drops?

Thanks,

Steve
 
sreilly24590,

Securing Vertical Joints. I secured all PVC joints with foil tape and sheet metal screws. However if the vertical drops are supported so that the pipe cannot drop, tape alone would likely be sufficient. If I am wrong and the joints begin to pull apart, sheet metal screws could be added at that time. I used ¾” wide Metal Hanger Strap to hold vertical drops in place.

In the method I used to secure joints, the foil tape went on first to make the joint air tight. Two sheet metal screws placed opposite one another secured the joint. The holes were predrilled and I tried not to penetrate the inner wall of the inner-most pipe. However, sometimes the inner wall of the inner-most pipe was penetrated by the drill bit. In either case, the sheet metal screws were short enough so as not to project into the inner air-carrying pipe.

I used SDR-35 pipe and either 3/8” or ½” sheet metal screws; I do not recall which length.

The joint was taped before adding the screws since it would make disassembling the joint easier. The screws could be removed and the tape cut. If the joint is first screwed together and then taped, the tape would have to be removed from the pipe or at least from the vicinity of the screws to disassemble the pipe.

Since the size of the drill bit was much smaller that the diameter of the sheet metal screw shank, air leakage is, I believe minimal to none.

6” x 4” Adapter. I agree that a smoother transition from 6” to 4”, as in a cone, would likely reduce turbulence compared to the low profile stepped style reducer.

I took a different approach, seeking to maintain air flow. I terminated the 6” pipe with a 6" x 4" D/C Adapter. If only one leg is needed, the second 4” leg can be capped or fitted with a 4” blast gate. The blast gate could be opened to whatever extent needed to maintain airflow in the 6” pipe. The 6" x 4" D/C Adapter is actually a 6” x 4” x 4” wye, where both 4” legs merge into the 6” diameter. It looks like this…

http://www.grizzly.com/products/6-x-4-D-C-Adapter/D4240
 
Thanks for the reply jsbrow. While in town yesterday evening, date night, I stopped and looked for some screws I needed and found these 1/2" self-threading truss phillips head self piercing screws. I had already taped all my connections with metal tape so I did pre-drill the holes and didn't worry about penetration as there is no air leak and the screwhead lands flat on the pipe/fitting. The screw just barely enters the inside of the pipe and I mean like you can barely see the very sharp tip. I secured the gates as well using the screws and tape. All tape was used 1st as I just added the screws.

What I was so surprised about after putting the screws in every joint connection was the rigidity of the entire assembly. I mean before I was happy with the piping but now it's so much more rigid with no movement at all. I probably went through at least half the box of 100 screws and it dawned on me that I can run the copper wire I have to ground the system should I want to. The information on the screws is:

Lath
Truss Phillips Self-Piercing
Zinc
#8 x 1/2 IN 100
#35267 Hillman

I found them at Lowes if that helps and they were the shortest I could find. The self-tapping sheet metal screws I had at home but as pointed out in another post the tips aren't threaded as they are designed to drill into the metal first and then thread in. What I particularly like about these truss head screws is the flat oversized head.

Back to grounding the system, the most I've noticed as far as static is concerned is enough to raise the hair on your arm when running the unit. I don't think it's anywhere high enough to be of a concern but I already have the thin gauged copper wire I bought for this back when I was planning out the system so I might as well use it and now with the screws it makes it so much easier. I don't see a need to do anything more than run the wire externally from screw to screw and securing to a valid ground which could be an electrical ground or a plumbing ground. I may be wrong but I don't think so, grounding from the conductor (pipe) is grounding. As long as there's a path to discharge you should be good to go. At least that's my theory anyway.

For what it's worth I used 6" blast gates from ClearVue and the 6" to two 4" box with separate blast gates at the router table they have as well. One on the fence and the other for the other for the dust collector box (part of the router table). See Crestonwood for the free plans if interested. I've been using the CV system for months now and I'm very pleased with it. I have two points that have not been finished where one is capped and the other has a blast gate temporarily installed. Now to install the Bin Sensor........
 
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sreilly24590,

I probably went overboard when I applied foil tape to piping as a way to bleed off excess static charge. I too was confronted with the problem of taping into a ground. My solution was to add a grounding screw to the outside of the larger Clearvue electric box. It involved drilling a hole in the box and adding a grounding screw on the outside of the box. Since 1) the CV electric box is grounded, 2) the pipe grounding system terminated at the cyclone, and 3) the CV electric box was mounted close to the cyclone inlet, this grounding method worked well.

If the entire grounding system is inner-connected, then another ground termination point could be one of your machines. In most cases the outer metal frame of machines are grounded. The ground could be permanently secure to a machine or an alligator clip added to the grounding wire and the alligator clip used to attach to bare metal on the machine. This ground would be lost if the machine was unplugged.

As an aside, while all my piping is grounded, I ran out of energy and did not extend the ground to the flex hoses. One effect of this laziness was the static electrical field that pulled on my hair and skin when fetching lumber from the outfeed table of the planer. Last month my annoyance at this static electrical field finally prompted me to action. I wrapped grounding wire around the two 4” pieces of flex hose (one piece of flex hose was PVC and the other polyurethane). The wire was terminated under one of the screws that hold the piping together. The screw offered continuity to ground. That tamed the annoying electric field.
 
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