Best modern way to cut old corrugated iron?

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geekIT

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#323799 16-Jan-2026 14:12

I'm still repairing a tin fence that was knocked over in the recent Southland big blow. About a hundred years ago when I built houses, abrasive fiber discs were the go-to cutters for tin or fibrolite, but now there are umpteen different cutting discs for grinder and skilsaw. Being a real tool fancier, I'd love to buy a Makita nibbler but I'm not about to spend $500\600 for something I'll only use for a few hours, dammit. Also, I've read about guys running old (non-carbide tipped) skilsaw blades mounted backwards after slimming down the teeth sides with a grinder, but I have a feeling my neighbors will not be thrilled by the likely noise.

I haven't a lot of cutting to do, so cutting disks for a skilsaw might be best. Any recommendations?

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#3453617 16-Jan-2026 14:18

If you have a circular saw https://sydneytools.co.nz/product/milwaukee-48408315-165mm-612-48t-medium-metal-circular-saw-blade

If you have access to an Air compressor Air nibblers also work great https://sydneytools.co.nz/product/chicago-air-cnib-12mm-air-nibbler

Stu1

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#3453620 16-Jan-2026 14:25

I just used a grinder , I wonder if these work ?

https://www.thetoolshed.co.nz/product/38065-toolshed-drill-shear?gad_source=1&gad_campaignid=17182567162&gbraid=0AAAAADLICtLOrZcWP8vg_IkPFuRvKP_1m&gclid=EAIaIQobChMI74aN1POOkgMVZ6hmAh2xajFAEAQYASABEgJrV_D_BwE

geekIT

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#3453628 16-Jan-2026 14:50

Thanks guys.

Shrub: LOL, the first option would work, I'm sure, but $98 is kinda expensive.

Stu1: Yeah, I'd already emailed that guy. He said no, it doesn't work on corrugated. Which is interesting as there are heaps of internet ads for this type of drill-addon tool and most of them include the word 'corrugated'.

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Bung

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#3453638 16-Jan-2026 15:23

geekIT:

I haven't a lot of cutting to do, so cutting disks for a skilsaw might be best. Any recommendations?

If you haven't got a lot to do don't write off the standard Gilbow style tin snips. If you don't need the edge to be too precise start the cut and tear the sheet across.

djtOtago

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#3453646 16-Jan-2026 16:59

There are Nibblers that fit Drills. https://www.thetoolshed.co.nz/product/266-toolshed-nibbler-for-electric-drill I've seen cheaper, just can't find a link to one 😊

I normally use something like https://www.mitre10.co.nz/shop/bosch-diamond-metal-wheel-cutting-disc-115mm/p/2036001 on my angle grinder.

But if it is long cuts I need to be exactly straight, I use my oldest tungsten skill saw blade backwards.

mdf

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#3453648 16-Jan-2026 17:04

Are you just cutting away old damaged stuff or the new stuff? How rough is acceptable?

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Sidestep

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#3454015 18-Jan-2026 22:39

I've just done a small roof (14 sheets corrugated galv) at the back of the farm with a metal cutting blade in a Dewalt jigsaw. Worked fine.

bebek

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#3454018 18-Jan-2026 23:23

One roofer I met told me to never use any saw. He use only nibbler.
He explained that saw cut will form rust sooner or later. Unfortunately. I forget the details of his explanation.

Bung

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#3454019 19-Jan-2026 00:00

According to the roofing manufacturers grinding wheels or power saws heat the cut edge and destroy the paint or metallic coating.

acsylaa

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#3454029 19-Jan-2026 08:40

This is Old School and seen it done many times by the old man who is a builder https://www.youtube.com/watch?v=xB77Bii3M0I

Senecio

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#3454033 19-Jan-2026 09:25

acsylaa:

This is Old School and seen it done many times by the old man who is a builder https://www.youtube.com/watch?v=xB77Bii3M0I

Nice, complete with the best quality safety jandels!

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bebek

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#3454168 19-Jan-2026 12:11

Bung:

According to the roofing manufacturers grinding wheels or power saws heat the cut edge and destroy the paint or metallic coating.

That's what I'm told too. Destroyed protective coating would lead to rust sooner. Nibbler cause acceptable (tolerable) low heat.

eracode

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#3454178 19-Jan-2026 13:00

How about hiring a nibbler?

Sometimes I just sit and think. Other times I just sit.

tripper1000

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#3454243 19-Jan-2026 14:55

For a small job, just use tin snips. Every man should have a pair in their tool box! I prefer the straight edged type, not aviation shears which create a horrible serrated edge.

I have used carbide tipped skill saw blades when I was feeling lazy and gash - I can't recommend it. It sent shrapnel everywhere at high velocity, so if you do, make sure you wear long sleeves, and use a really good set of safety glasses or better - a face shield, and don't do it near a car or anything with a nice paint job that you want to stay nice.

mdooher

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#3454290 19-Jan-2026 15:12

Not having access to a nibbler I have done each of the following at one point:

Tin snips, works fine for a small job but if you are office worker you might need a sleep after cutting a couple of sheets, your forearms will be sore for days

Metal cutting blade in a jigsaw, again works fine but the entre suburb will hear what you are doing... you, and your helper will need good hearing protection

Carbide fine tooth blade into a circular saw backwards... Now this will be loud enough to annoy everybody in the entire district.🙃 You will need to double plug if you attempt this. To be fair I would never do this again... it's pretty dodgy.

As others have pointed out the two last methods will tend to encourage rusting, not that I have ever seen it. but make sure you brush off all the swarf, that will mark your iron when the little bits rust.

Matthew

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