Cutting sheetmetal roofing material

I'm pondering the same issue. If a die is used, how do you handle angled cuts?

I don't know how your roofing material looks like.

If that sheet is flat: I have cut tin sheet with a circular (hand) saw. Just had carbide tips with a negative rake on the blade. If it is not flat, give it a try. You need a circular saw that does deep enough cuts.

Nick

A plasma cutter would do a good job of it.

Pete C.

The shops that form up the sheets from continuous roll stock use a flat shear, and cut to length just before forming.

The shops that custom cut from pre-formed stock use a shear with a profile matching the corregations. That's why those shops will never angle-cut a sheet for you, whereas the fab shops can.

Most of the galvanized roofing suppliers will void the rust-out warrantee if you use a saw to cut the sheets -- although most of the barn builders around here to just that, with a diamond blade. The suppliers say that only a "wiping" cut that tends to smear the galvanizing and pinch it shut at the edge will preserve the rust resistance of the sheets. They'll cancel your warrantee in a New York minute if they see a sheet that's been sawn.

LLoyd

The type of shear that's used on stove pipe ought to work. It cuts out a narrow strip of metal. Since you don't have to lean or tilt the shear, the cuts are clean and square. They are available in both hand and electric versions.

The pole barn builders I have seen use the shear for the straight cuts and a tip snips for the angled cuts. A saw causes a bur that is hard to get rid of, a plasma cutter leaves a hardened edge that will wreck your snips if you have to adjust a cut. Steve

I used a regular general purpose carbide blade in 'skil' saw. Ear plugs AND muffs! Full face shield and hat -to-boots heavy duty rain gear. The noise is unbelievable and hot, sharp metal sprays everywhere so protect or remove bystanders. This is an ugly job but this method works. Just bite the bullet and do it. BTW don't expect to have much of a saw blade after this treatment.

Regards. Ken.

I have used an airtool called a air nibbler, I have cut the 29 gauge Galvalum 5v panels with ease with no distortion. My roofing panels are 26 guage but I have not cut this thickness with the nibblers. I think this would be easy to follow the profile with this tool. The tool cost about $30US and it will cut 16 gauge metal.

search for nibbler @ harborfreight.com

You might try the guys at Dynamic Fastener- they supply the pole barn building industry with tools. They sell all kinds of blades for skill saws, air and electric nibblers and shears, snips, and every kind of fastener, gasket, and accessory for metal roofing and siding.

Its true that in industry, they basically dont cut the stuff- they order it the right size. They use snips and nibblers to cut out notches for vents and windows, but try not to cut full sheets.

I have used my motorised plasma torch, and it works fine, but it does indeed leave a heat affected zone that is hard- so you have to cut it once, the right size, or else snips will get damaged.

If the method you use leaves bits of metal or abrasive (anything other than a nibbler or shear) make sure you clean things completely so the bits don't rust and discolor things, and so they don't get into the joint and grind holes in the paint (it'll cause premature panel failure- a rust hole.).

Dave

BTDT and the blade gets hot and wobbles to beat heck in anywhere from 1 foot to 3 feet of cut depending on the situation.

Pull the saw from the sheet and leave it running in mid air and as soon as it cools it'll be straight again and dive into it again. :)

I thought about cutting slots into the saw blade but chickened out. :/

I wouldn't use a carbide tipped one even if you paid me, no need when cheaper and safer ones can be had. Mine is still good enough to make knife blades from, why I still had it to start with.

Since then, finally found one of the factory made blades for cutting sheet metal, one of them that has -no- teeth, just slots to keep it from wobbling when hot, but haven't used it yet.

You'll do a better job with that stuff on, (if nothing else;).

I use a knife then a file.

Also I don't know nuthin about wet places or waranties but the theory is... the zinc plated on the steel (anywhere that also gets wet) will try to protect the -exposed iron- too.

Tin coatings do just the opposite, BTW.

"the little spot of iron is trying to protect the whole surface of the tin by sacrificing itself" -metallurgy teacher

"all corrosion is electrical" -same dude ;)

Alvin in AZ

Get a carbide steel cutting blade - I prefer Tenryu, Morse, or DML. These chips are cool and the edge is burr free. They work really well on angle iron and structural steel.

They can be run with a conventional circular saw, but there are many special built saws that turn a bit slower and catch the chips. Here is one:

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RoyJ wrote:

At 26 gauge I would expect any decent plasma cutter to cut so fast that it would hardly touch the paint past the immediate cut area. As an example, my Hypertherm manual indicates 26 gauge recommended parameters of 25A arc current and 353 IPM travel speed.

Pete C.

Metalcutting blade for thin stock in a circ saw. Here in Australia they're commonly available, Makita sells one as do a number of other companies.

Noisy and spew hot chips, but fast, a relatively clean cut and a lot better than abrasive disks. You do tend to chip the carbide teeth if you're not careful/lucky, but what the hell, it works.

Done it myself a lot so I speak from experience.

PDW

Wear a full face mask and long sleeves!!

Fully ACK! Didn't mention that.

Nick

Get a friction blade for your Skil saw. They are designed to cut sheet metal with minimal distortion. The blade has no teeth, just some radial slots to prevent heat buckling. They are very fast on sheet metal panels. Bugs