Black pipe or tube, what do you know?

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Hello all,I know there is a difference between black pipe and/or tube but I don't know if there are two types, the type I am referring to is black tube as I will be using it for construction.So I would like to know first of all, 1- is it easy to weld with a mig welder2- Is it strong?3- what are it's main uses? Thanks, Little sparky
Reply:Hello all, here is a bit more information for those who would like it. Thank you.I am currently building a homemade chopper trike and have come to the front forks. This build is pretty much just built from what I can research, look at and then make it how I think they made it, no plans. In saying that my research is very very intense so I havnt taken any shortcuts, I've done it properly. Now I am going to make springer for suspension for it and have seen that a lot of people use DOM tube but from where I come from in Australia the costs of buying and shopping that stuff in is just ridiculous when all you want is around 2.5m in total. So I have thought about using black tube/pipe but would like to know a bit about it as I don't have time to research for hours and hours with the bit I am looking at only on hold at the steel factory for very limited time.So I would like to know first of all, 1- is it easy to weld with a mig welder2- Is it strong?3- what are it's main uses? Thanks, Little sparky
Reply:not a item to start taking short cuts, unknown don't use
Reply:Chopper trike?  Is this something with a 5 HP lawnmower engine or a big motorcycle?  Little short forks or some ungodly long and severely raked tubes?"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Originally Posted by OldendumChopper trike?  Is this something with a 5 HP lawnmower engine or a big motorcycle?  Little short forks or some ungodly long and severely raked tubes?
Reply:Could be black water pipe. It's some kind of cast iron, and they used it a lot in old houses. My suggestion is to either contact the manufacturer, or take a bit of excess and do a spark test.
Reply:Using non-technical jargon as a reference prior to giving advice here in the U.S. will sometimes give you the wrong answer, but to do so for what is available in Australia is just asking for disaster. By black pipe are you referring to the black version in the photo below. If so, yes it is easy enough to weld with a MIG welder; fairly strong material, but realize it is pipe with a seam running down it's length and not seamless DOM or other type of tubing and main use, here in the U.S., would be for compressed gas (air, residential natural gas, etc.) systems. Best guess, and that is all this is, not a great material if you were planning on running your trike down the street, but probably, if the speeds aren't too fast, okay for the backyard...all of this depending upon the rake angle you'll use.Lincoln PrecisionTig 275Miller 251Miller DialArc 250Bridgeport millHossfeld bender & diesLogan shaperJet 14 X 40 latheSouth Bend 9" 'C'Hypertherm 900Ellis 3000 band saw21"Royersford ExcelsiorTwo shops, still too many tools.
Reply:Pipe tolerances for roundness and diameter are a bit more loose than tube.  Pipe is almost always welded seam whereas tube steel may or may not have the seam.  Black pipe generally has a coating (tar in the old days...more like paint these days) that can screw with welds and finishing.  You can get it uncoated but not as easily.  It's become relatively expensive compared to the old days because China has been sucking up the raw scrap steel that pipe is usually made from--and even sometimes hard to get larger volumes (we go through hundreds of 20 footers at a time and sometimes have to battle to find stock)  I'd personally bite the bullet and get tube rather than pipe, even if there is a bit more cost. It'd make a better end product for reasons of tolerance, finish and likely strength.   However, at the low HP you are talking about it implies that you don't need superior strength and freeway-speed perfection so I wouldn't exclude pipe from the option list.
Reply:little_sparkyDOM and TIG.If that doesn't work for you - I'd go with . . .  Originally Posted by teh603Could be black water pipe. It's some kind of cast iron, and they used it a lot in old houses. My suggestion is to either contact the manufacturer, or take a bit of excess and do a spark test.
Reply:Seamless tubing would be the best to use. Standard type pipe like you buy in the hardware store isn't good for structural welding. There are seamless grades and seamed grades of pipe used for structural welding though so it can be a little confusing.
Reply:In reality, not that it is correct, a lot of people use sch 40 for a lot of things. What is emphasized across the spectrum of using it beyond it's intended purpose is do not use it for mission critical / safety structures. The connecting point where the forks connect to the triple tree / head structure is a mission critical portion of an MC's design, even more so if it's raked.-NicheLast edited by NicheFab; 02-05-2015 at 04:19 PM.
Reply:Originally Posted by NicheFabIn reality, not that it is correct, a lot of people use sch 40 for a lot of things. What is emphasized across the spectrum of using it beyond it's intended purpose is do not use it for mission critical / safety structures. The connecting point where the forks connect to the triple tree / head structure is a mission critical portion of an MC's design, even more so if it's raked.-Niche
Reply:Schedule 40 can be many types of pipe. It's a pressure rating not a material specification. Oddly finding out the actual pressure rating is not easy to find.
Reply:Originally Posted by Welder DaveSchedule 40 can be many types of pipe. It's a pressure rating not a material specification. Oddly finding out the actual pressure rating is not easy to find.