Welding Pipe Perpendicular

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Hi there- I have a pipe welding question I hope some of you pros can answer.I am welding pipe perpendicular to each other.  I received the great advice to make a "bird's beak" in this forum, and that works pretty well, but I still have gaps between the pipes.  I've spent quality time with the grinder but can't seem to get it totally flush.Do I just need to try harder?  Or will my weld joint be strong enough with a weld to close the gaps?  I've attached some pictures to show what I'm talking about.  Since I need this frame to be able to bear weight up to 150 lbs I need to be certain my welds are strong. It looks to me like I can do it in one pass.   Its just currently tacked but its been hell getting it to fit this well.Thank you! Attached ImagesLongevity Weldmax 520DStick/Tig/Plasma CutterSonoma County, CA
Reply:Personally, I think it would be more than adequate the way you have it.  the more important issue will be making sure you get good penetration on the weld.  150lb isn't anything for a structure like what you have unless it's hanging way off a lever arm (like at the far end of that pipe you're welding on).  Got any pictures of the whole project?Millermatic 135Syncrowave 250
Reply:The tighter you get the fit, the easier it will be to weld. The bigger the gap, the more likely you are to melt back the edge and have a larger hole to fill. Run colder so you don't melt the edge at the gap, and you are too cold to get good penetration on the rest.It's possible to get that fit tight enough you have trouble getting a piece of paper thru the joint. It just takes the right tools or lots of practice. Pipe notchers that use holesaws, or mills, or press notchers will make short work of getting a nice tight fit every time. They just cost lots of money for the good ones. HF has a fair holesaw notcher that will work for the occasional job, and careful selection of the hole saw will get you a fairly decent fit that can be touched up with a grinder. Coping pipe by hand is as much an art as a science. Some can do it almost as fast as one can with a drill type notcher.If it's not super critical structurally you may be able to build the low area up first and then regrind to fill some of the gap before you actually weld it up. The other thing that will work if you are not fitting between 2 pipes is to scribe the joint. I often take a piece of soapstone and use that to mark an even line all the way around, then grind to the line for a tight fit. The trick is to keep the stone in the same plane as the pipe you are fitting. IE. if you just follow the curve of the main pipe, you will have a radius that is too large. You need to visualize where the pipe will fit, where the gap is and where it needs to be trimmed.Last edited by DSW; 07-01-2010 at 03:44 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Hello Stormy,Not meaning to split hairs, but the title of your thread is welding pipe perpendicular, and I open it up, and you are talking about TUBING and your joint intersections are not perpendicular.The "Bird Beaks" you are referring to is commonly called "Coping" when talking about roll cages, and tubing work.  Doug (DSW) gave you some excellent information.You never stated what your application was, or how you caluclated that the joint will be subject to 150lbs of load, but for a non-race application, you can weld up the joint as-pictured, and you should have no issues with a 150lb load.Now, if for some reason, this joint is actually part of a cage structure for Racing, or Off Road applications, or you are building up skills for that end use, you should concentrate on getting the centerlines of your tubing to intersect better, coping the tubing so that your joints are tighter, and maybe work on the cleanliness of the materials a little.Pictures show that your tubing is coped slightly offset which causes the centerline of your Intersecting tubing to be out of alignment with the centerline of the intersected tubing - In some applications this is necessary, but whenever possible, try to keep the legs of your coped "even" and try to match up the centerlines of both pieces of material to equally share the load from one member to another.No Offense is intended by my comments, but I take cage work, and the protection of human lives very seriously in the world of motor sports.Last edited by Black Wolf; 07-01-2010 at 04:05 PM.Later,Jason
Reply:Hi Jason, DSW and Mot Krig,Thank you all for your responses.  Hmmm... tubing vs. pipe - please explain the difference- its 1" and 3/4" pipe.The application isn't racing, its an art piece.  Take a look at my avatar image for instance.  I create a metal frame then put fiberglass over it.  I have never worked with pipe before, and this frame needs to be guaranteed not to break for its lifetime if a 150lb kid sits on it.  Its a low sculpture for children to play on (only 2.5' tall, 4'8" long) (will post a pic of the whole frame later - not too far along yet)What I'm gathering from the responses is that it is good enough for my application... if it were going to be an adult junglegym 25 feet high however, it would need to have totally flush "coping" - am I correct?The problem for me with the coping was that I ground down each edge to fit excellent, but when put into place, the bends in the 1" metal set off the alignment for the coping - no longer such a tight fit.  Nothing I'm working with is a straight pipe.The top bars offset I thought would be stronger embracing the top part of the pipe as opposed to totally centerline perpendicular - if someone was jumping up and down on them the downwards force would not be able to push through.  Right?  Or are you saying centerline is still better?  (Hmmm... tapping into my ancient physics knowledge...)Thank you for your time and suggestions, all.Longevity Weldmax 520DStick/Tig/Plasma CutterSonoma County, CA
Reply:i would say what its for it good enough as long as its a good weld. if you want a better fit up just keep grinding your contact points until its nice and tight. i've made several cardboard stencils over the years to help quicken up the process, which i think they now sell at even tractor suply stores...lol... but if your going to be doing alot of this, what i did was get it to a nice and tight fit up, then make a stencil out of it. works like a charm. i had fitters that didnt even need things like that, but they did the **** day in and day out. i weld and work on everything, not just pipe, so i did what i had to do to make it quicker and its the cats *** every time. i know this is a little off subject here, but i figure you and others that read can take note of this.
Reply:I think you need to work on your technique, not only are those gaps harder to weld, you'll put more heat into the whole product which will warp the snot out of it! Unless you're really good at heat shrinking things back into shape, better work on your fits. http://metalgeek.com/static/cope.pcgiDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Stormy,A couple of points.You can't weld air.  Meaning that with a gap between pieces, you have air and that means that the weld has to bridge across the gap while simultaneously melting JUST enough of both pieces to fuse nicely to both.  Which is a bit tricky as you have the 'end' of one piece of pipe and the 'middle' of the other piece of pipe.  With enough power to melt nicely into the 'middle' of the pipe, the 'end' will melt away.  With less power to just melt the 'end' of the pipe, the 'middle' of the other pipe won't melt enough.So what you have is making the welding a bit tricky (I don't know your skill level, experienced welders can and do weld 'stuff' like that).  Basically, what you have to do is direct the arc at the 'main' pipe and get a weld puddle going there and then you 'wash' the arc and filler and puddle up onto the edge of the smaller pipe until you get that to start to melt a little, and then you swing back down to the 'main' pipe and repeat all of that until the parts have reached a Zen-like state of Oneness.  Better fit-up ALWAYS makes the welding go easier.And when the gap between the pieces is as big as the thickness of the material, then that is even trickier to weld together.Next, although you say and show what you have as "tack welded", even your tack weld looks like it didn't penetrate much into the 'main' pipe if at all.  It looks like the weld is just glopped on top of the pipe and didn't melt into it at all.  As long as you realize that and make sure that your final welds fuse and penetrate (melt into) the steel properly, no problem.  If you make your final welds such that they are just glopped on top of the steel, then that would not be good.Having the 'outside' line of the smaller pipe line up with the 'outside' line of the larger pipe is fine, and different diameter parts are sometimes put together that way.  But you still have to make sure your welds are good no matter how you line up the parts.And fitting a curved piece of pipe to another curved piece of pipe is not the easiest thing to do.But I'd say to mark the points that are touching from the 3/4 pipe and grind/cut them down a bit.  Then check the fit again, and mark the new points that are touching.  Grind those down a little and repeat until the fit is a bit better all around.Interesting project and please post some follow-up pics or more in-process pics.  We like pictures of stuff.    The best laid schemes ... Gang oft agley ...
Reply:Thanks guys - especially Moon Rise for your in-depth response.   Yes my tacks suck, have a new stick welder I'm not used to yet, need to do some more practice runs before I do the actual weld, was penetrating at that setting but now doesn't seem to be... or I'm melting the rod too fast-I did already grind each point as you suggested, and now my bars are almost too short with over-grinding, which is why I thought maybe I should just go for it, gaps and all.  Its impossible to match both sides of that pipe into a fitted structure - argh!  (the same pipe is welded on both ends on different 1" pieces which have been carefully shaped)Enough to go nuts already. OK sounds like I need to bust them off, and make my beast a little shorter with more grinding.@Hammerwelder- I can't even imagine how you are making a stencil for this - got any pictures?  Mind you, coping for a curved piece of metal is uneven all the way around - different sized indentations on each side.  I'm very curious.Thanks!Longevity Weldmax 520DStick/Tig/Plasma CutterSonoma County, CA
Reply:Originally Posted by StormyWhat I'm gathering from the responses is that it is good enough for my application... if it were going to be an adult junglegym 25 feet high however, it would need to have totally flush "coping" - am I correct?  To make it perfect and easy to weld, yes, but I still maintain that anybody with experience at welding could weld what you've got and make it incredibly strong.The top bars offset I thought would be stronger embracing the top part of the pipe as opposed to totally centerline perpendicular - if someone was jumping up and down on them the downwards force would not be able to push through.  Right?  Or are you saying centerline is still better?  (Hmmm... tapping into my ancient physics knowledge...)I think you're analyzing it way too much.  Much more will depend on your ability to weld it and get the proper penetration.  With the way in which the force is being applied I think you're thinking about it wrong.  i think you're thinking about it as if the force was being transmitted down linearly, when in reality it will be rotational around the weld joint.  Anyway, before I get too in depth just worry about your fit up and welding it properly.
Reply:Originally Posted by StormyI can't even imagine how you are making a stencil for this - got any pictures?
Reply:Originally Posted by StormyI did already grind each point as you suggested, and now my bars are almost too short with over-grinding, which is why I thought maybe I should just go for it, gaps and all.  Its impossible to match both sides of that pipe into a fitted structure - argh!  (the same pipe is welded on both ends on different 1" pieces which have been carefully shaped)Enough to go nuts already.
Reply:Ok I found a tube cluster and a coped piece in the scrap bin. I was helping a friend learn to cope tube this spring.#1 the cluster we were working on.#2 Coped joint ready to weld#3 Coped tube#4 Paper template made from coped tube.#5 Paper template shown ready to reproduce coped joint. Just trace with sharpie then cut and grind to near line and finish for perfect fit. Attached Images.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by CEPDid you not see the link I inserted into my post? Plug in your numbers, print the page, cut the lines, place over your tube, mark, cut grind. http://metalgeek.com/static/cope.pcgi
Reply:Originally Posted by Hammerwelderthanks for posting this bud,