What is the best way to cut spiral pipe?

[Rick Potter]

Any ideas on neatly and quickly cutting 8" and 6" spiral dust collector pipe?

I have a 14" abrasive saw, and have thought of lowering the blade partially into the pipe, locking it with the chain and rotating the pipe. Never tried that, it sounds a bit iffy.

Also have a sawzall with a long metal blade, but I think that would be difficult to get a clean, straight cut.

Never had much luck with metal shears, especially when I come to a seam.

All suggestions appreciated.

Rick Potter

[Alan Turner]

We did a lot of this when we installed DC at PFW. Take a large regular screwdriver and hammer it into the pipe at an angle, using the corner of the screwdriver to cut a gash. Then use a jigsaw with a metal cutting blade. It is quick and easy. Use a marker for the line. Only takes a minute or so per cut.

[Rob Russell]

If you're a tool junkie, it's an excuse to buy a metal-cutting bandsaw. I have one of the little 4"x6" jobs that run about $200 and it has long paid for itself. You'd probably want one of the larger ones - a 6" x 9" (cut part way through the pipe, then roll it for the rest of the cut) or a 8"x10" if you want to do everything in single passes.

The metal cutting saws are all imports until you get to some of the bigger ones.

[Chris Padilla]

My DC system was mostly plastic but I had some metal work to do in order to hook up blast gates and flex line but these shears worked very well...but, yeah, seams were a bit tough.

The jigsaw sounds like a great idea and pretty darn fast, too. I used it to cut up some derelict duct under my house in order to get it out.

[Scott Velie]

I would use my corded sheet metal "nibbler" after punching a hole.

[Matt Meiser]

I'd use a plasma cutter an set up something so I can rotate the pipe and keep the torch still.

Since I'm guessing you don't have a plasma cutter, I've seen it done with cutoff wheels in a 4-1/2" angle grinder. Harbor Freight's 4-1/2" angle grinders are one of their good buys and you could get out of there with a grinder and a box of cutoff wheels for about $20.

[Chris McKimson]

I marked the cut all the way around the spiral pipe with a magic marker, started the cut with a hacksaw then completed the cut with the jigsaw. Worked great.

Chris

[Rick Potter]

I will try the jigsaw method, unless someone gives me a plasma cutter.

Rick P

[Denny Rice]

I have a automotive tool that has small circular roatating blades on a chain that is adjustable with a 12" handle. I bought it at my local NAPA store, it is designed to cut tailpipes and muffler pipe it worked great for me. I think it cost about 20 bucks,you just rotate it back and forth till it cuts through the pipe. Very clean cut.