Assembling Spiral Pipe

[Sean Nagle]

I'll be assembling the ductwork for my Oneida 2.5HP Gorilla in the next couple weeks. It appears that I'm able to locate 26 gauge spiral pipe locally for a better price than any online snap-lock pipe. However, I'll be purchasing my lateral wye's from Oneida and my adjustable elbows from KenCraft.

I've looked all over the web as well as this forum for some clarification on spiral pipe assembly. Everything I've found says that fittings are inserted into the spiral pipe on both sides rather than crimping the downstream end of the spiral pipe. Do I need to crimp the upstream end of the fittings for insertion into the spiral pipe? Doesn't this cause a friction point? How have others here assembled their spiral pipe?

[Tom Veatch]

HVAC ducting is crimped to reduce the diameter and allow it to fit inside the mating duct/fitting. Spiral pipe fittings are sized to fit inside the mating part without the necessity of crimping. It's similar to PVC pipe and fittings in that respect (except PVC pipe slips into the fittings).

http://www.airhand.com/downloads/Installation.pdf

[Rick Potter]

I guess it comes both ways Sean. When I got my 26 ga spiral pipe from a local AC supply house it was in 10' lengths with crimping on one end.

Rick Potter

[Sean Nagle]

HVAC ducting is crimped to reduce the diameter and allow it to fit inside the mating duct/fitting. Spiral pipe fittings are sized to fit inside the mating part without the necessity of crimping. It's similar to PVC pipe and fittings in that respect (except PVC pipe slips into the fittings).

http://www.airhand.com/downloads/Installation.pdf

Thanks for the explanation. I did run across Air Handling System's document. However, I'm still confused concerning the fittings. Oneida doesn't appear to offer two flavors of fittings, though they do offer spiral pipe. I'll have to inquire with Oneida. So if you commit to one system, you really can't change your mind "midstream"

[Sean Nagle]

Thought I'd post an update. I talked with Oneida this morning and they recommended using all sorts of adapters with their spiral pipe. They claimed that a spiral pipe system would run twice what their quoted HVAC system would run and isn't required for a cyclone less than 3-5HP.

I also got a quote from Spiral Manufacturing today. They listed 24 gauge spiral pipe and 20 gauge lateral wye's and 20 gauge, die-cast elbows... very heavy-duty. Their fittings are made specifically for spiral pipe and the die-cast elbows eliminate the need to tape-up segments. They are also smoother than segmented elbows for improved airflow. Even with $180 for freight shipping, they are priced only about $50 higher than Oneida's HVAC-type system. I should mention that I am buying blast gates and flex pipe elsewhere since I am able to find better pricing and I'm also not including any of Oneida's recommended cuffs and stuff.

[george wilson]

I had to buy the reduced diameter,short pipe couplers to slide inside my spiral pipes. They have to have sheetmetal screws run through them after assembly. They fit inside the pipes and have a humped ridge in their middles so they cannot slide all the way into one pipe. I drilled holes around the pipes after inserting the couplings,and put in 3 or 4 sheetmetal screws. Then,wrap them around the joints with the silver coated tape they sell (which,by the way,NEVER hardens) to seal the pipe better. Penn state sells the couplings and the pipe tape,too. It can get to be a bit confusing doing the fittings. I used only smooth elbows.They have less frictional loss than jointed elbows. There are probably places where you need the adjustable elbows,though.

[Rick Potter]

Sean,

I posted this tip a while back when I put in my system. I went to a local wholesaler of HVAC supplies. He was glad to sell me the 26 ga spiral pipe I mentioned with the crimp on one end. He also sold me a whole bunch of 26 ga. fittings, elbows, and such. All in stock, just pick them up, they sell it all the time.

I was doubly fortunate to meet an AC contractor, who let me buy at his price. The system cost less than half of what the Oneida pipe and fittings cost.

The only catch was that, like Home Depot HVAC, you have to flatten the corrugations on the elbows, and reverse the flow. This was another thread.

I cut the 10' sections of pipe on my 14" abrasive chop saw (you cannot cut 8 inch with one stroke, by the way). I bought a crimper to recrimp the pipe pieces I cut.

I used pop rivets for a solid connection, and as mentioned in an above post, used aluminum tape, which I also got there, to seal the joints. In my previous shop I used duct tape....big mistake.

Hope this helps,

Rick Potter

[george wilson]

The aluminum tape I used had an adhesive on one side that was supposed to harden. It hasn't hardened in years. The sheet metal screws and internal couplings hold my pipe together.the tape just keeps air leaks down in my experience. Good thing you riveted.