# Cutting Corrugated Steel Roofing



## Eric Johnson (Sep 14, 2007)

I need to cut a couple of 10-inch diameter semi-circles out of some galvanized, corrugated steel roofing. I use tin snips to make straight cuts, which works OK. But you can forget about doing anything remotely fancy with those things. At least I can. For long cuts, I use a metal-cutting blade in a Skill saw, after donning the safety glasses and earmuffs.

Tools I have at my disposal include: Sawzall; Dremmel; Table Saw; Hand-held circular saw; Drill

None seems terribly promising. In my experience, tin work just plain sucks.

Any suggestions?


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## BrotherBart (Sep 14, 2007)

Eric Johnson said:
			
		

> I need to cut a couple of 10-inch diameter semi-circles out of some galvanized, corrugated steel roofing. I use tin snips to make straight cuts, which works OK. But you can forget about doing anything remotely fancy with those things. At least I can. For long cuts, I use a metal-cutting blade in a Skill saw, after donning the safety glasses and earmuffs.
> 
> Tools I have at my disposal include: Sawzall; Dremmel; Table Saw; Hand-held circular saw; Drill
> 
> ...



Funny you should mention that. I am just now taking a break from cutting a piece of sheet metal. With a hole in the middle. A couple of weeks ago I bought a pair of right angle aviation snips and they are the best thing I have ever seen for the task.

The night I bought them I sat and cut semi-circles in scrap galvanized 22 gauge tin grinning from ear to ear. I have done it a Skill saw and metal cutting blade but man was it ugly. With a big U.


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## wahoowad (Sep 14, 2007)

Probably not the answer you are looking for in a DIY thread, but since I too learned that tin work sucks, I found my local sheet metal shop does small jobs like this surprisingly cheap. Depending on what you are doing it might be worth a phone call to check. Or a welder shop might knock it out with a plasma cutter cheap too.


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## Eric Johnson (Sep 14, 2007)

Both excellent suggestions. Thanks.


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## elkimmeg (Sep 14, 2007)

I would use a fine tooth blade in a saber saw and rig up a good  support system under the metal and cut a disk just the right size clamp it on the top and use as a prefect template to cutting a perfectly round hole then it you need finer edges dress them up witha file


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## BrotherBart (Sep 14, 2007)

elkimmeg said:
			
		

> I would use a fine tooth blade in a saber saw and rig up a good  support system under the metal and cut a dick just the right size...



That has just gotta hurt.

Edit: When I saw that I laughed so hard I almost fell out of the chair. Had to quote it to save it for posterity before he came back and changed it. Which he did.


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## Hogwildz (Sep 15, 2007)

BrotherBart said:
			
		

> elkimmeg said:
> 
> 
> 
> ...



LMFAO! Thats all I got to say about that.

On a serious note. A sawzall with a fine metal blade works. But the decking must be secure as not to vibrate all over the place. Less vibration makes it cut smoother.
I have a few sets of right & left hand tin snips, they work very well also. The depending if your going up or down is which ones you use. I mean you use both, the rights will get where the lefts can't & vise versa. It will be a workout for your hands though. Elk also has the right idea. The whole idea with sawing metal roofing or metal decking is to keep the metal secure while cutting. If its vibrating, thats just letting you know the metal is moving up & down with the saw blade and doing more moving then actually being cut. I would not recommend sawing you know what to any size smaller .


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## MrGriz (Sep 15, 2007)

LMAO...Beer through the nose has got to be bad for you....

What about a little 4 1/2" grinder and a cutting wheel?  I've done similar with mine.


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## Hogwildz (Sep 15, 2007)

That works, but hard to keep metal from pinching wheel sometimes, can be tough to keep that from happening & staying on mark. Plus  that means carborundum blades, and the steel roofing or decking will eat em up. Also depends on the thickness of the metal. Not too mention hot sparks


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## MrGriz (Sep 15, 2007)

I didn't say it was a good idea..... ;-) 

I've never cut steel roofing with mine, but I have made it do a few other tricks on various projects.


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## Hogwildz (Sep 15, 2007)

I used mine along with a sawzaw to hack the damper opening in my old heatilator to let me run the Summits liner straight onto her. It was kinda fun doing destruction, but sparky, dirty, and I was well glad when it was done. Was one of those fun first time, wouldn't want to do it again any time soon.


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## keyman512us (Sep 15, 2007)

Eric Johnson said:
			
		

> I need to cut a couple of 10-inch diameter semi-circles out of some galvanized, corrugated steel roofing. I use tin snips to make straight cuts, which works OK. But you can forget about doing anything remotely fancy with those things. At least I can. For long cuts, I use a metal-cutting blade in a Skill saw, after donning the safety glasses and earmuffs.
> 
> Tools I have at my disposal include: Sawzall; Dremmel; Table Saw; Hand-held circular saw; Drill
> 
> ...



Two Words...Plasma Cutter. 

If you don't have any friends that have one...??? Check around at a local Auto Body shop or two... or perhaps a small welding metal fab/job shop.

Once you've used one..."Ya just gotta have one....lol":

A little pricey...But I got sick of "old fashioned" metal cutting. A few '161 Preps' on steel doors and that little unit has paid for itself.
Works great and it plugs into just about any standard outlet:
http://www.thermadyne.com/uplFiles/litLibrary/thermaldynamics/63_2209.pdf

"Being able to cut a rusty muffler out without a facefull of rust and not damaging the pipe back past the CAT...Priceless!"

It only gets used "every so often" but it has paid for itself to say the least!


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## Eric Johnson (Sep 17, 2007)

Thanks again, guys.

If I was the kind of person who could actually measure something accurately, then the plasma thing would be the way to go. However, I know from experience that I'd have the thing cut and then wind up hacking into it with a shears, so I bought the curved shears, a la BB's suggestion, and they worked great.


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## velvetfoot (Sep 17, 2007)

Would these work with circles?

http://search.harborfreight.com/cpisearch/web/search.do?keyword=nibbler


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## Gibbonboy (Sep 17, 2007)

These are what I use for just about all of my curved sheetmetal cuts. Straight cuts get done in the brake. 
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92148

We cut steel roofing for years with a carbide blade turned backwards in the circular saw. I would not recommend this unless you are wearing full body armor. 

The snips are the best small-scale solution. If you were going to do lots, the nibbler is the way to go. You can rent shears from most places that sell steel pans.


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## myzamboni (Sep 17, 2007)

Curious, would a Rotozip work?  http://www.rotozip.com/SiteLanding_Page.htm


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