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chopperrr
08-23-2011, 10:04 AM
Hi guys!
I finnaly got an O/A rig. I plan to do sheet metal work and maybe some steel work. I have a few books so I am still in the process of learning.
I do not yet have a cutting tip. Can I cut sheet metal with a welding tip?
Or if I want to heat a steel pipe in order to twist it, what tip is the best for this, a rosebud?

Thanks!

Rasper
08-23-2011, 04:25 PM
You could melt through the metal, but cutting with a cutting torch uses pure oxygen and burns the metal; in fact you can turn off the acetylene after the metal starts burning. The best way to cut sheet metal on a low budget is with snips. Or with an electric jig saw on high speed.

To heat pipe, it depends on the size of the pipe. For 1/2 inch or 3/4 inch pipe, any welding tip should do.

Richard

chopperrr
08-23-2011, 04:47 PM
I guess it would be for "decorative yard art". I want to make stuff like tables and chairs, combining wood, glas and wrought iron. But I would not be using iron, but for example a square steel tube, heat it and twist it to have the apearance of wrought iron but be lighter.

For example, my mom has a flower shop, so I want to make a Lilly themed table for the shop. The flower petals and leaves would be made out of sheetmetal, and the stem maybe out of twisted rebar and so on...

dmc1
08-23-2011, 08:50 PM
I would say you need a cutting torch to get full use of your O/A rig.

As Richard says , you can use a welding tip for heating relatively small stuff, but for heating larger stuff, too much of the heat just goes off into the air while you're waiting for the temperature to come up, wasting your expensive gasses.

For larger stuff, I use a welding torch, without the cutting oxygen, of course, but only because I don't have a rose tip. It doesn't seem to be very efficient, and with the now high cost of gasses, I don't do it nearly as much as I used to.

I'd like to hear comments about rose tips, having never used one.

Dave Cameron

olcarguy
08-24-2011, 06:21 AM
You can cut thin sheet steel with a welding tip, use a oxidizing flame to burn away the unwanted material. As the others have said, it is not the most practical. Even with a proper cutting torch the cut is messy at best, normally needing a lot of prep to get a good edge because of slag buildup. Invest in a metal cutting chop saw for large stock, use snips or a zip wheel on a grinder for sheet stock, they will do a much better job with almost no prep after the cut. If you are using your largest tip for heating, build a small enclosure with some fire bricks to contain the flame [regular bricks will/can explode] to minimize heat loss. Just my thoughts......Roy


I lurk a lot, not much to say......

Bill Gibson
08-24-2011, 06:24 AM
There is a technique called "flushing". Generally done with a cutting torch where you set your flame to a highly oxydizing setting. Almost to the point of blowing out the flame and you can make almost surgical cuts flush with the side of a piece of metal. It's a technique that is used to cut out welds without cutting into the parent metal. To do it you start with the tip set normal, and when the material gets orange hot, you turn the oxy valve open untill it starts to cut without using the oxy lance/lever. This technique can be used with a welding tip to cut thin sheet metal, but it's really not the best thing to do, because you can damage the tip.
It would be better to get a cutting torch head and get a 00 tip. and set your gas pressures at about 2 and 15. With that, you can make decent cuts in ferrous sheet metal.

bobadame
08-24-2011, 06:43 AM
I spent a year working for Union Pacific RR fixing bashed up freight cars. We would use a rosebud tip for almost everything even cutting. The trick was: heat the steel, usually a big rivet head, with the torch then just fold over the fuel line and crank open the oxygen line. Not very precise but it was fast.

pro70z28
08-24-2011, 10:13 AM
But I would not be using iron, but for example a square steel tube, heat it and twist it to have the apearance of wrought iron but be lighter.



You may have trouble with the tube collapsing if you twist it like wrought iron. A solid square twists pretty easy.

Ian Bee
08-24-2011, 01:25 PM
You may have trouble with the tube collapsing if you twist it like wrought iron. A solid square twists pretty easy.

Agreed. More than likely, you will separate the ERW along the side.