DC Duct Questions

[Bill Arnold]

OK, so I got my Super Gorilla installed and adapted into some existing temporary flex tube I've been using on some of my tools. Oneida provided free duct layout -- CAD drawings and BOM/Pricing. Now I have sticker shock for sure! No doubt the pipe and fittings they specified are worth the price, but I have a couple of questions.

How well do the typical A/C snaplock pipe and fittings work in a DC system? I know the wyes are backward, so I'll have to address that matter.

Is it better to use silicone seal or aluminum tape on the joints?

By the way, the little bit I've used the Gorilla so far tells me all I need to confirm it's a great machine. Example: when I connected my old 1.5hp/1100cfm DC to my 13" planer, chips would still fly around a little; none got loose with the Gorilla connected and two 4-inch ports open.

[Jim Becker]

You can use commonly and locally available 26 gage snap lock, but I suggest you consider buying long-radius adjustable elbows and laterals (wyes) from a dust collection specialty firm...if not Oneida, maybe Kencraft. Also check out local suppliers for spiral. Many times you can get it for the same or similar price as snap-lock and it's much better in the long run. Make your own blast gates to both save money and preserve duct diameter...the commercial units don't fit the pip snugly and also have a thickness that is detrimental to top performance.

Foil HVAC tape is the best for sealing most joints. In fact, it's strong enough you can use it for the physical connection rather than pop rivets outside of high-stress areas. (Near gates, etc) if you want to use a sealer, on your adjustable elbows, for example, use HVAC caulk, not silicone. It's silver in color and designed for the job. You also avoid potential silicone contamination in your shop.

[Roy Wall]

Bill,

I got my stuff from Oneida...it's a heavier guage (28?...24) than std hvac stuff down at the Borg.....it was a little more.......but I was okay with it.

I use aluminum tape and silicone. Silicone for the 90* angles on blast gate locations.

Happy 2hp gorilla owner....

[Cary Swoveland]

Foil HVAC tape is the best for sealing most joints. In fact, it's strong enough you can use it for the physical connection rather than pop rivets outside of high-stress areas. (Near gates, etc) if you want to use a sealer, on your adjustable elbows, for example, use HVAC caulk, not silicone...
Good advice all around, Jim. I would suggest using the foil tape only--no sealer. The foil tape gives a good seal and it's a lot easier to change the layout of the system in future (which one will do) if no sealer is used.

For flexibility and efficiency, I suggest you standardize on 5" blast gates (except maybe a 6" for a TS or large planer). For machines with 4" dust ports, terminate the 5" flex hose at a 5"->4" reducer attached to the machine's dust port.

Lastly: do not paint the ducting! It's a real nuisance when you change the ducting a year later. You might ask who would consider painting ductwork, wyes, blastgates, etc. Just don't direct that question to me.

Cary

[Jim O'Dell]

How far are you from Tallahassee FL? I understand there is a spiral pipe manufacturer there that will sell to individuals at a good price. If interested PM me and I'll get the information to you. Jim.

[Tom Jones III]

I'm in the process of doing what Jim suggested. I used all borg cheap stuff and taped it together. I have spent a little time monkeying around with the layout and I am going to slowly replace parts with good DC ducting.

[Steven Wilson]

You may want to take a look at what Oneida designed and see if you can simplify the duct work. Although you can use lighter hvac snap lock, I found the Oneida snap lock wasn't out of line price wise. In the smaller HP systems (say under 7.5-10hp) you don't need the heavy duty (and expensive) elboes and can do nicely with the adjustable ones. By simplifying my ductwork design I ended up with a couple of locations with stacked wyes (say a 6x5x5 attached to a 5x5x5 to get three 5" ports dropped off a 6" line) and a fairly simple system - and simplicity equates to less materials and a lower price. Since my main machine (MiniMax CU350) is really helped with quick disconnects I decided to spend the money and equip my machine hoods, flex hoses, and blast gate terminations with Nordfab QF fittings. Now that was expensive (and money well spent IMHO) but the basic system fittings were reasonably priced. As for other pieces, I mainly used pop rivets to connect the ductwork (some sheet metal screws when needed), Duct hanger strap material to hold up the ductwork, and silicon calk to seal the ductwork. The silicon caulk stays put and doesn't affect finishing, unlike using silicon sprays in your shop. Once done I used some smoke to find leaks. I found that pop rivets were easy to use if you use an air powered pop rivet gun instead of the manual kind. I also used an air drill which made the process a bit easier. You'll also need to sharpen your drill bit(s) fairly often. You may also want to look into an air nibbler for cutting the snap lock, and a hand crimper comes in handy. I picked up my air tools at harbor frieght and they were good enough to last through this project.

[Michael Lutz]

My local Menards carrys 26 ga. snap lok pipe for less than Oneida. When I bought my Gorilla, Oneida did a duct design which I simplified to get a system that would work. I have a single 6" pipe with 4 drops on it on a 10' wall, so it is mostly fittings. The local HVAC fittings are a thinner gauge material with a tighter bend, so I went with fittings from Oneida. I used a few sheet metal screws and taped it all up with aluminum tape. I did it that way so I could make changes as needed or dismantle it all easily if I were to move.

Mike

[Adam Grills]

I did some calling around when I was installing my system and I got 6" 16ga spiral at a local company specializing in air movement systems for less than the 6" 26 g snap lock at a lumber yard or box store. You will find that the spiral is very stiff and great for long runs. I marked the pipe square to the end all the way around and cut it with and angle grinder outfitted with a zip blade. Cuts like butter!
As you, I was on a tight budget and the 6 x 6 x6 Y's, 45's etc from HD have to do for now. But they work. The silver HVAC tape is sealing the joints.
Adam

[Jim Bell]

Go to the Clearvue web site and check their links. I ordered 40' of 6'' thin wall pvc and all kinds of fittings for less than anyone else had theirs listed.

[Bartee Lamar]

Can you tell us which link you used on Clearvue. I am guessing it was McMaster Carr, but then where did you find it in their catalog.

I am arguing with myself about PVC vs Spiral rite now, so I am very interested.

Thanks....

[Bill Arnold]

Thanks to all for your input. As always, this group has plenty of information to share. I'll check into the sources you guys have mentioned. I'm less than an hour from Tallahassee, so will get the contact info on the spiral source. I'm definitely going with metal duct to avoid the static issues. :eek:

Interesting that Adam got wyes from HD. When I asked about wyes at the blue borg, the guy said they don't even have a catalog to check on them. I'll check with HD while in Florida this week.

The layout Oneida did is a good guide, but there are several changes to fit the real world. Since I've got a temporary setup with my old flex, I plan to take my time and try to do the duct right. I still have to finish placing paneling and pegboard on the walls and paint the ceiling before I can put up permanent duct, anyway. :confused:

[Adam Grills]

Bill,
I am in Ontario Canada. So maybe the cold weather here and the increase in use of duct work for heating they have different stuff in the HVAC section. They were in stock here. They did look at me funny when I had a box and a half of them:) Left them with none in stock. They should still be able to order them for you.

[Jim Becker]

The issue with HVAC wyes is that they are both "backwards" and usually poorly constructed...resulting in a lot of leakage and the need to do a lot of extra work with the foil tape. HVAC wyes were not designed for the "vacuum" environment; rather they are best suited to the slightly positive pressure that home heating and air conditioning systems provide. Fine in a pinch, but ordering from Kenkraft, Oneida or Air Handling Systems gets you the real deal and usually a smoother transition.