Plasma cutter safey

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Hello, Tom here, brand new.I have limited knowledge of Plasma cutters. I was discussing them with someone and they claimed that when cutting steel with a plasma cutter, you can touch the cut edge with your bare hand in less than a minute. I understand that plasma cutters do cut faster than the standard cutters (oxygen/fuel?), but it surprised me that would be possible.However I was under the impression that was dependent on the IPM. I can see where a CNC plasma cutter that cuts at say 400 ipm the metal might be safe to touch in under a minute since it was exposed to minimal heat build up. But we were talking about a video we were watching of a person operating a hand held plasma cutter where they cut a 24 inch diameter in a large steel pipe. A hole large enough for an adult to fit through. The operator's speed of moving the cutter seemed no faster than normal, meaning I will guess 8-10 ipm. Wouldn't the cut edge be just as hot with it being cut that slow?
Reply:I'd say the cut pieces are just as hot as with O/A.  I have the scars to prove it Well... maybe it's not at *exactly* the same temperature, but it's above "ouch that hurts" and below glowing red.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Thank you Andy.So am I understanding right that a plasma cutter's advantage in terms of the cut edge being safe to touch would only apply if it is executed with an increased IPM?In my scenario of the video I provide in my earlier post, I was telling him that with it being a hand held plasma cutter operated by a person instead of a computer controlled machine (programming the IPM at high speeds), the line of cut is simply not performed fast enough, heat build up will occur just like a standard cutter. Or if there was any difference, it would be a matter of only a few seconds sooner that it would be safe to touch.I said it would take several minutes before that 24 inch diameter edge would be safe to touch, he said it would be safe to touch in less than a minute.Maybe he's trying to get me to burn my fingers by trying it? lol
Reply:A lot also depends on the thickness of the base material and also between material type ie aluminium or steal. Good luckGod speed Happy weldingSent from my Desire HD using Tapatalk 2
Reply:It depends. Thin sheet cuts quick on the bench, and you can grab it quick, no problema. If you are gouging out some restricted bracketry under a fenderwell and you burn into it for 4 or 5 minutes straight, it will glow red. City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Ive found that after most cuts the metal is cool enough to put my tongue on it..............if you dont believe me, try it.
Reply:heheyou also have to have enough air pressure (assuming you have enough current) so that it blows ALL of the molten metal from the cut-line.  If any lingers around on the underside, it will obviously transfer heat into the metal as it cools.
Reply:Thanks all, and Larry0 you're bad, haha.Oscar. the fire sparks were certainly visible but are you saying if the proper air pressure is present, you would additionally see molten level spitting from the other side?
Reply:IIRC a plasma actually cuts at a higher temp than O/A.I beleive the plasma stream can be as high as 30,000 degrees farenheit, whereas O/A  puts out about  around 3500 degrees.The difference is the HAZ.  Because the plasma has a small HAZ it cools faster, and distorts less.You can burn yourself on any freshly cut piece of steel."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by LarryOIve found that after most cuts the metal is cool enough to put my tongue on it..............if you dont believe me, try it.
Reply:Thank you everyone for your answers. The video we watched was a movie scene from Aliens 1986. After cutting a 24 inch diameter in a large steel pipe, a character was touching the edges with her bare fingers about 45 seconds after making the cut. I thought it would be too hot to touch, he said no that was enough time to cool off. Maybe it wouldn't have given her third degree burns, I don't know, but the very least I thought it would be hot enough, that it would make a person involuntarily coil back, maybe even cause blistering.So I got the ammo I need thanks to you all for when I talk to him again.
Reply:Thank you everyone for your answers. The video we watched was a movie scene from Aliens 1986. After cutting a 24 inch diameter in a large steel pipe, a character was touching the edges with her bare fingers about 45 seconds after making the cut.
Reply:Lol, that's true, but I don't think they're fire proof.
Reply:Originally Posted by TomFHello, Tom here, brand new.I have limited knowledge of Plasma cutters. I was discussing them with someone and they claimed that when cutting steel with a plasma cutter, you can touch the cut edge with your bare hand in less than a minute. I understand that plasma cutters do cut faster than the standard cutters (oxygen/fuel?), but it surprised me that would be possible.However I was under the impression that was dependent on the IPM. I can see where a CNC plasma cutter that cuts at say 400 ipm the metal might be safe to touch in under a minute since it was exposed to minimal heat build up. But we were talking about a video we were watching of a person operating a hand held plasma cutter where they cut a 24 inch diameter in a large steel pipe. A hole large enough for an adult to fit through. The operator's speed of moving the cutter seemed no faster than normal, meaning I will guess 8-10 ipm. Wouldn't the cut edge be just as hot with it being cut that slow?
Reply:You assume they were using a Plasma Cutter, considering the fact that they used Pulse Rifles I doubt they still used technology from the 21st century to cut that hole.Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:yeah, that wasn't a plasma cutter it was an anti matter beam generator, you could touch it even seconds after the cut, it doesn't cut by heating the metal at all, it cuts by making the matter in it's stream into antimatter miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:I've learned the hard way....don't touch it with the bare hands.......works every time.Working without welding gloves around hot metal always means eventually you'll grab or touch something that is hot....happens too quick to get back from.Ian..
Reply:Originally Posted by Broccoli1You assume they were using a Plasma Cutter, considering the fact that they used Pulse Rifles I doubt they still used technology from the 21st century to cut that hole.