DC leakage. Does it matter?

[Rick Potter]

When I installed the 3 HP gorilla a few months ago, I sealed all connections with aluminum tape, but I didn't seal all the seams in the elbows. My rich buddy says I am losing a lot through them, but I am not sure I believe that.

There are 19 elbows, some 8", mostly 6" and a few 4". I don't feel anything when I hold my hand near them.

Does anyone really KNOW if taping them will really make any difference??

Rick Potter

[Dewey Torres]

If you are trying to match Bill Pentz it might but for the rest of the world no. Especially since you say you can’t feel suction with your hand.

Hook it up and try it for a while. If there is a leak there you will accumulate fine dust particles in that area.

[Jim O'Dell]

Or get you a stick of incense, and let the smoke from it tell you if they are leaking. It should actually suck the smoke in if there are leaks. Might make the shop smell, well, different too. Jim.

[Jim Becker]

You can tape them (I did) and it does reduce leakage, but taping is a thankless task on elbows. The better choice, however, is to use HVAC caulk...and when I re-do them, that's what I'll use.

[glenn bradley]

My machine ports are still 4". During testing prior to deciding on my duct setup I found that opening an unused gate part way helped my air flow. Knowing this I lowered my concern for any very minor leaks at joints. If I find there to be a problem after some use, I'll start a thread. So far, everything's great.

[Rick Potter]

Sounds like I shouldn't worry about it too much. The 19 mentioned elbows are the ones I didn't seal, after sealing the first half dozen or so, and getting anxious to get the system going. As for the incense, I have tried eau de chili beans, but no luck finding leaks.

As for the open gate, Glenn. I have a 4" and 2 1/2" going to my RAS. I have never closed the four, and have no gate on the 2 1/2". That is also my safety valve in case I accidently shut off all the gates.

I guess I will wait till I have a free afternoon, before I worry about sealing the rest.

Thank you again, creekers.

Rick Potter

[Sonny Edmonds]

I think your rich buddy is fulla beans, or the after effects anyway.
What is it? A DUST COLLECTOR SYSTEM, right?
What is it going to collect at any minute leakage points? Hummm, could it be any airborne dust in the air in your shop?
And if it does collect any airborne dust, it will get caught in the final filter and isn't that kinda what you want?

Mine is PVC and the joints are taped because I did not want to ram screws into this set-up to make it more rigid. So I used black 20 mill pipe wrapping tape that is like thick electrical tape. It stretches to conform and hold.
I've never really cared for that aluminum tape stuff.
I do have some metal work in my system though. For an odd angle connector, nothing would fill the bill like the 6" adjustable black stovepipe elbow I worked into the scheme of things. I didn't tape it or seal it in any way.
Because... it sucks in. So any air going into it is getting filtered. Oh Joy! Oh Rapture!

I would more be asking if all those adjustable elbows are hindering your system from friction and air flow disturbance?

If you want to best your rich buddy, put a dirty air booster blower in your system and suck his hair implants out with the new boost in performance. That'll fix'm!

[Mark Hubl]

I agree with what has been said. Small leaks not a problem. Your saw, planer, jointer all have leaks. Without them you wouldn't be moving air and that is the working concept of the dc...move high volumes of air...unlike a vacuum which creates high pressures to move smaller volumes of air.

Also, as mentioned, sometimes a little air from downstream of a collection point can help keep things moving in the duct. Air like water will follow the path of least resistance so unless you are creating a situation where the DC is wanting to pull more air than can be supplied by the outlet at the tool your leaks are probably pretty minimal. If not just open another blastgate a bit. Just my two cents.

[Jim Becker]

I will agree that small leaks will have little impact on system performance...but they will add noise!

[Chip Lindley]

Leaks are only a problem IF your DC system does not perform as you expect. Ask yourself, "Does the system pull sawdust from each machine as you expect it to?" Only if your 3hp Gorilla fails to perform, do you need to obsess over its leaks. OR, hand your rich buddy a roll of tape and tell him to Git Er Dun!!

[John Keeton]

Like the others, I doubt there is enough leakage to matter, but as Jim says, the accumulated noise from that many elbows may add up. A $5 tube of silicone and 30 minutes will eliminate the issue though. Jim suggested HVAC caulk, and that would certainly work, but I found that silicone flowed easy, I could spread it around the elbows with my fingers, and it doesn't show. Be careful on the metal edges! They can be sharp!

If you ever need to move one of the elbows, or change the angle, you can run a safety knife around the joint and cut the silicone.

[John Bush]

Hi Rick,
My cyclone is in an attached shed and is quiet enough that I can easily hear the leaks. I used an old mechanics trick of using a piece of flexible plastic tubing as an earphone and "scoped" each joint for noisy leaks. I used conventional HVAC pipe and fittings with the gray duct sealer the pros use. A gallon is ~$10, applies with a disposable brush, and goes a long way. Only down side is it's not as pretty as the shiney duct tape.
You can easily seal joints that are hard to wrap the tape around. Not sure about performance, but the shop is a lot quieter.

[Joe Chritz]

It cuts noise (as Jim mentioned) and if you have a system that is already taxed it can help. Every leak is air that isn't being sucked out at the port. Mine is sealed with silicone in some areas and foil tape in others.

There isn't any danger to running the machine with the ports closed unless the pipes collapse. The motor uses more HP with more gates opened, not the other way around. It seems counter intuitive but it is what it is.

Joe

[Rick Potter]

Thanks again guys. With 26GA spiral pipe I am not really worried about collapsing a pipe, but I had been told it was better if some air was always flowing.

I find it very interesting that the elbows can make the unit noisier if they leak a bit. Since my unit is pretty noisy, I am going to seal everything as soon as I have time.

Rick Potter