spiral ductwork help

[blackbird]

anyone have any tips on cutting spiral duct work so it looks good.

[amickracing]

plasma cutter
sawzall
jig saw

if you need help marking a straight line around it, go to a welding shop and get a pipe tape... them are handy!

[tinmantu]

to cut it to length I use a kett shear...depending on diameter should be able to cut 99% of it, then use sawzall to cut seam. Cutting in registers I square from floor snap a chalk line on top and have a cardboard pattern, trace, use a 3/4" stepdown bit to start and use snips to cut them out, bulldog snips to cut the seams....don't do enough to justify a plasma cutter but a sawzall will work also.

[slimwoodie]

plasma
grinder

[heatpumpguru]

If you are going to paint it get the stuff that you can paint,I forget what it is called ask supply house.

[Chuck 999]

If you are going to paint it get the stuff that you can paint,I forget what it is called ask supply house.

Its called Iron Grip and apply generoulsly it will shrink, depending on size of spiral dont cut the seams..the duct is under tension and the top and bottom of the cut will blow out, leave the seams and cut out your register taps, sprial duct is something not to be attempted if never done before...Ive ran litteraly miles of this style ductwork...hanging it to make it look professional and level is a experience in itself, many different ways i.e threaded rod, 16 gauge hanging strap with proper circumference bend, 1/2 belly band with companion flange and rod...I've seen some bad spiral jobs. As far as cutting follow the circumference of the pipe at your cut measurement and make hash marks with a sharpy and then follow up with a sawzall, its loud but quick..

[amickracing]

Also, you can get spiral that's made out of paint lock, or paint grip.. (probably a dozen other names too). Basically a metal with a primer already on it.

[zzonko]

We NEVER cut the seams. The spiral will warp and weaken, Also internaly mastic the connections and use a full circumfrence hanger strap to the top of the bar joists. There are many methods of cutting the pipe.

[amickracing]

We NEVER cut the seams. The spiral will warp and weaken, Also internaly mastic the connections and use a full circumfrence hanger strap to the top of the bar joists. There are many methods of cutting the pipe.

Wow, never cut the seams? Bet them are some looooooong trunk lines!

Another "trick" is to throw a 1/8" pop rivet in the seam. Of course, best to do this before you do the cutting. I've done this a few times and it seems to work great to keep things together.

[blackbird]

hey thanks to all, i got some good advice.

[zzonko]

Wow, never cut the seams? Bet them are some looooooong trunk lines!

Another "trick" is to throw a 1/8" pop rivet in the seam. Of course, best to do this before you do the cutting. I've done this a few times and it seems to work great to keep things together.

To clarify.

We do cut the pipe for length. But we do not cut the seams for the grill boxes

[tinner73]

4 1/2" grinder with cut-off wheel............and safety glasses.

<-----like these

[tinknocker service tech]

electric side cutting shears
work great and can cut to 18 gauge

[Dirty-SMW265]

(my two cents)

...personally....i prefer a reciprocating saw to cut spiral....i've seen guys that use a grinder with cut-off wheel....and it looks really nice...(i couldn't get the hang of it...so i stick with what works for me)

...when you're done cutting your piece...take some time and trim off those barbs left from the diagonal cut seam...not only on your piece...but also on the drop-off...your partner will appreciate it...

...and whoever tells you NOT to cut the seams for your take-offs is 100 percent correct....(the larger the spiral the more important this is)

[acmech13]

sawzall works best for me. then i mastic my seams. really nice looking jobs. i kinda miss working with the stuff.

[ar_hvac_man]

Just did a small spiral job. Reducing trunk line. I used sawzall for the pipe lengths and unibit to start the holes for my registers then snips. I used the curved registers, not the boxes. How can you install the registers without cutting the seams??