Metal piping for DC

[John Branam]

I am working on the lay out of the shop at my new house and I am going to start with the DC system. I want to use metal pipe, my question is what guage does the piping need to be and if you have used metal piping how did you ground your system?

[Frank Hagan]

Most recommendations I've seen call for 24 guage or better metal pipe (the higher the number, the thinner the metal, so you want your ducting to be 24, 22, etc.). 30 guage is common at Home Depot in the HVAC department, and people have had problems with it collapsing (at least that's what I've heard!)

Metal pipe grounds itself at the DC and the tool (if its a metal port). I don't think you have a problem if its grounded only at the DC.

[Andy Hoyt]

About 1/2 of my ducted tools are grounded through metal to metal contact from machine to DC by virtue of the ducting. For the others I used flex tubing for the last couple of feet of the run to the machine and stripped out enough of the heavy gauge wire in the tubing at each end to continue the grounding.

[Bob Dodge]

Hi John,

I think you'll find that gauge will change depending on diameter. A manufacturer may go with 24 ga, up to a diameter of 5", then 22 ga. to 6"-12", etc. Other manufacturers will sell all one gauge regardless of diameter. Depends on the application.(positive/negative pressure)

You won't have to ground metal pipe. It'll 'ground" at the dc housing.

Small pipe manufacturers are located everywhere, they're just not very visible to the average consumer. Go to a local heating and ventilation contractor, and find out where he/she buys their pipe.

Bob

[Tom Jones III]

I use borg style thin ducting on my dust gorilla and it works fine. Of course DC style ducting will have better wye's and elbows, and the crimping is reversed. However the cost savings is enormous. The only time I could imagine ducting collapsing is if you leave the pipe open on one end. The fittings add a tremendous amount of strength.

[Chris Damm]

26ga. is OK. Just stay away from 30ga.

[John Branam]

Is 26 ga ducting typically a readily available product at a BORG?

[Bill Lewis]

26 ga. ducting has only limited availability at HD. I think it's only 5" diameter and short lengths of pipe. My opionion and experience is that 30 ga. is fine for 4". 26 ga is more than adequate for all pipe sizes up to 7".

Have you done all of the other selections first? When designing a system, the piping comes after you have sized the collection unit.

For more information that might be helpful to you, check out this post (http://http://www.sawmillcreek.org/showthread.php?t=17408) I did way pack when I was installing my system and piping.

[Jeff Singleton]

In my shop I have a 7 1/2 Aget cyclone and use 22 ga. spiral pipe in 10" and 6". It is nice and stiff. Check with fabricators in your area and also HVAC distributors for spiral pipe. For fittings try Stamped Fittings in Elmira,NY, they had the best price by far even with shipping and their stuff is 20 & 22 ga. I also grounded my cyclone with 2 ga. bare copper to a 8' copper rod outside as recommended by an industrial dust collection contractor here in town. Good luck

Jeff Singleton;)

[J.R. Rutter]

Ditto on the spiral pipe - when I found my local maker via an HVAC outfit that I've used for other things, he was happy to make pipe to length for cash for about the same cost as snap lock! He also made up a bunch of inside collars for joints, which make it easy to connect everything. Super rigid, easily sealed, bombproof, relatively inexpensive (if you find a local source), and Borg fittings will work with it (reinforcement with something akin to contruction adhesive works well to seal them).

PS - I managed to collapse my old snap lock setup when I plugged in my new blower this past fall.

[Jim Becker]

24 or 26 guage is what you want. If you can source spiral locally for a good price, go for it. Otherwise, snap-lock works well in these heavier guages.

[Frank Chaffee]

Is there a way to economically support lighter gauges of pipe to prevent collapse?
Frank

[Jim Becker]

Frank, if your system leaks enough, there is no danger of collapse. It's when you "build it right" that the danger creeps in with metal that is too light and flexible...right about when you slam the only open gate closed with the high-performance system running...scrunch! 24-26 guage can be sourced from HVAC outlets, Oneida, Kencraft, Air Handling Systems, etc. The 'borg doesn't have to participate in the transaction. ;)

[Frank Chaffee]

Frank, if your system leaks enough, there is no danger of collapse. It's when you "build it right" that the danger creeps in with metal that is too light and flexible...right about when you slam the only open gate closed with the high-performance system running...scrunch! 24-26 guage can be sourced from HVAC outlets, Oneida, Kencraft, Air Handling Systems, etc. The 'borg doesn't have to participate in the transaction. ;)

Thank you Jim,
I can understand how a thin annular ring would collapse under vacuum. When I try to visualize a circumferential band supporting a pipe, I see it only working with a very heavy band, which would not be an economical choice in favor of using lighter pipe.

What I wonder here is if a light spirally wrapped wire or strap could prevent collapse. Perhaps even solder or screw-clamped somewhere along its length.

A concept beyond my ability to calculate, but one I need to ask Creekers about.

Thanks,
Frank

[edit] Been awhile, I guess that is not an annular ring after all.

[Bill Lewis]

What I wonder here is if a light spirally wrapped wire or strap could prevent collapse. Perhaps even solder or screw-clamped somewhere along its length.In a word, No. Longitudinal stiffening will do almost nothing. Spiral wound begins to address the problem but a wire woundn't add any strength. Basically what's needed to stiffen a cylinder is cicumfrential stiffeners or frames, like that on a submarine. But Why Bother. It all sounds like a whole lot of work to save very few dollars.
OTOH If you have an existing undersised pipe in your system that you are afraid might collapse one day, forget about it, If it hasn't done so already, it won't.

[John Branam]

Thanks everyone for the input. I will have to check on the spiral pipe ducting. There is a company around the corner from my office that manufactures it but I am not sure if they sell to indviduals. I will have to find out though.

[Mike Monroe]

I went to my local HVAC company that installed and services my furnace. They had all a the piping and fittings I needed. What they didn't have they made. I can't tell you the exact gauge but the stuff is stiffer than what the BORGs have.