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Tonyz
7th April 2018, 01:13 PM
Was trying to open an old thread 2011 but it appears its been shafted to metalwork forum and does not appear in their search engine and while I wait to be excepted maybe someone can give me the quick answer I'am after.

The tread was about putting a small nic in a sheet of corro and then ripping it accros with your hands......my question how sharp is the edge? not worried about rust forming etc its all second hand anyway...

BobL
7th April 2018, 01:49 PM
It sharp.

rwbuild
7th April 2018, 02:35 PM
Very sharp, when was your last tetanus booster needle?

Tonyz
7th April 2018, 02:39 PM
Thanks gents thats what I would have thought....onto plan ......hmmm what ?

damian
7th April 2018, 03:05 PM
I make raised plant beds out of old corro, I've got heaps laying around my block. I use an angle grinder, like a hot knife through butter. I suppose there must be a reason to do it another way but maybe try that first ?

BobL
7th April 2018, 04:29 PM
My experience with the tearing method was it worked OK across the corro but not so good along the corro.

The main reason for not cutting NEW corro with an angle grinder is that iron dust can bury itself in the galv and rust.
So if you don't care about that then using angle grinder is not a problem.

Aviation snips are not that easy to use on morrow but with a bit of persistence its possible and they do provide a relatively safe edge provided you don't constantly restart the cut on a section that has already been cut where by you end up with a heap of very nasty barbs. You have to be prepared to really bend the two cut surfaces away from each other as you go. This is not too bad across the corros but harder along a corro - try laying the snip over a bit more.

The same applies to electric shears - across the corro is dead easy but you have lay them over along the corro. They do generate a very safe edge similar to the aviation snips.

To removes the awful burr generated by using an angle grinder then a small flap wheel like this in a power drill is easier to use than most other things
433166

dazzler
7th April 2018, 05:05 PM
That thread also had other ways to cut.

One is to reverse an old blade on a circular saw and cut with that. I used this method on the farm and it works.

Neighbours will love you.


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Tonyz
7th April 2018, 05:20 PM
the thread was around putting a nic/cut in the edge of cooro, then one foot planted firmly on the good piece and grab the off cut with both hands...gloves if your a sook or wise and pull upwards, moving your foot to keep the good piece flat on the ground...its so bl***y fantasticly easy and quick. Yes the soothsayers will scream but try it.

I knew it worked but needed to work out if I needed a little extra to fix between timbers. I dont really need to, but will do it.

62woollybugger
7th April 2018, 10:12 PM
To cut it along the corro, score it the full length with a stanley knife, then grab one edge & give the sheet a whip crack. It'll just break along the score line, I wouldn't believe it until I saw it done.

KBs PensNmore
8th April 2018, 12:27 AM
I've done similar to Wooly, instead of the Stanley knife I used the last tooth on a handsaw, under the handle.
I got shown that trick when I was 15 by a builder.
Kryn

rob streeper
8th April 2018, 12:35 AM
To cut it along the corro, score it the full length with a stanley knife, then grab one edge & give the sheet a whip crack. It'll just break along the score line, I wouldn't believe it until I saw it done.

I'd love to see it done.

Bohdan
8th April 2018, 12:38 AM
I have used the TC tipped scratcher that is made for scribing cement sheet as it was handy and worked well.

OK with the corrugations but a bit messy across them.

If you want to use a grinder use the stainless cutting wheel as it leaves a lot less iron fillings to stick to the gal and leave rust marks.

BobL
8th April 2018, 10:23 AM
Another tip to prevent the iron chips leaving rust masks when using an angle grinder is to mask the Corro using old pieces of corro either side of the cut.
As the old corro laid on top won't always get you right up to the cut line I also used wide masking tape along the cut line and cut through that. .
OK for one or two cuts but a PITA when there are more than this to do.

Chief Tiff
8th April 2018, 03:45 PM
Wow; wouldn't have thunk it possible if I hadn't seen it done...


https://www.youtube.com/watch?v=370W-GJ6PDU

quercus
9th April 2018, 08:22 AM
If you put a straight edge across the top of the ripped pieces you will see some scalloping in between the ridges- not a problem if you are flashing it- but may affect the finish of your job.


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BallaratBill
9th April 2018, 02:26 PM
To cut it along the corro, score it the full length with a stanley knife, then grab one edge & give the sheet a whip crack. It'll just break along the score line, I wouldn't believe it until I saw it done.Knowing my awesome luck, I'd end up scalping myself. Not that there's much hair left to worry about [emoji23]
Any vids about showing this method?

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GaryJ
24th February 2021, 06:49 AM
Reviving an old thread but does anyone know if the snip and tear method across the sheet also works on Trimdek profile?