Sheet metal cutting

[luccass_j]

Just a quick question what do you guys use to cut out rotted metal?

To cut my sheet metal Ive got the best results with jig saw and snips but whenever I use my grinder the cut is never straight I was wondering if it was a matter of practice.

 

[brianblock]

I find you can get pretty straight with a 1mm slitting disc following the idge of some masking tape

 

[luccass_j]

I also have cut off tool but I haven't used it for a while as I found the same problems as with grinder although its easier to control.

 

[Wendelspanswick]

I use a 1mm slitting disc in a 4.5" grinder, no side handle fitted, just hold one hand on the body of the grinder. It helps if you have a decent grinder with a slim body.
Another tip is just to use the edge of the disc, don't plunge it in and cut as although it cuts faster the disc dissapears even faster and it also leaves a bigger burr.

 

[langy]

Plasma or thin cutting disc in an angle grinder

 

[Kent]

Whatever I can get in and cut it best with
I think the main issue is nobody can guess a square straight line - you have to lay it out first. Of course there is a bit of practice involved

 

[Shedendman]

I can cut a better straighter line with a slitting disc than i can freehand plasma,its the same ole thing,let the tool do the work

 

[cianh91]

Depends on what it is grinder is generally first to hand

 

[outofthefire]

Use a thin disk get your cut started dead straight on your line, keep a good bit of disk through the cut and it will help keep the grinder straight and work your way down the line. If you run the disk back and forth along the line cutting through gradually you've more chance of running off. I usually hold the body of the grinder with my right hand and keep the fingers of my left hand on the steel and my left thumb on the guard to keep it steady.

 

[luccass_j]

Thanks guys I presume its a matter of practice.

 

[gordon stephenson]

Thin cutting disc or plasma, Using the cutting disc is just like hack-sawing to a straight line etc, With pracitice you keep your eye on the disc while cutting and make very slight adjustments all the time to keep on track, It becomes almost second nature and happens automatically without having to think too much about it. You can also cut some quite decent curves by just cutting through the thickness of the sheet and no deeper,

 

[cianh91]

As said practice makes perfect with most things people have habit of thinking they'll just pick up a grinder and know how to use it after a while you learn the little things which make your cuts straighter and your speed faster without trying as hard

 

[graffian]

As people have said anything that will cut, my favorite weapon was probably my air saw.

 

[gordon stephenson]

Dont sink the disc to full depth, if it starts to wonder off line you won't be able to get it back on track,Sometimes I will just score the surface with the disc edge before doing the actual cut.

 

[Kent]

Dont sink the disc to full depth, if it starts to wonder off line you won't be able to get it back on track,Sometimes I will just score the surface with the disc edge before doing the actual cut.

Its funny some think you get a better cut doing exactly the opposite of that! Me? depends on what and were I face it! I literally spent weeks on end just grinding when I was an apprentice but I cant say its that accurate a way of cutting good straight lines in sheet and certainly nor RHS and pipe. Use what you have though if you haven't got a Guillotine to hand that will handle it which most have not

If you need a straight cut in sheet generally you wont better and type of saw that can cut to a straight edge clamped firmly to the work piece

 

[fixerupper]

Yes with all of the above ,I spent a bit of time working with sculpture students...with all kinds of materials wood ,metal, plastic,expanded foam, and cutting straight and curveing lines freehand was a thing they all found tricky .
Its about confidence ,but it's also about getting set up and confortable with the work secured and your balance ....jeff...

 

[Kent]

a bit of know how and a lot of practice like most things eh?

 

[Wallace]

Vehicle dependant but rotted metal I start by scaring the life out of it with a needle scaler* to locate what's solid and work from there with the plasma for big bits and a 4.5" 1mm cutting disc wherever possible and a 75mm air cut off tool with 1mm discs if I can't get the grinder in. Air chisel can be useful but lacks the finesse of a hammer & chisel and sometimes a hand operated nibbler.

New sheet I prefer to use the Gabro Notcher if I can as opposed to snips or grinder but the plasma makes short work of an 8'x4' sheet to get it down to a manageable size. A 32tpi blade in the bandsaw is OK on sheet but a plasma cut edge kills a blade in milliseconds if you don't check first! Sheet metal nibbler had been mostly redundant since having the Gabro Notcher.


*Did this on an SJ410 once and all sorts of horrors started falling off around the vehicle, wasn't much holding it together other than the mechanical fixings!

 

[cianh91]

If it's a new sheet its laser all the way

 

[luccass_j]

Thanks guys I did cut some scrap metal over the weekend and after deburring the results were amazing I used marker to draw a straight line and I cut it with just the edge of my disc. I couldn't believe the results I'm going to practice cutting some surves.