Re: Welding question

Posted by trucker40 on January 30, 2010 at 09:56:11 from (69.148.162.167):

In Reply to: Re: Welding question posted by 135 Fan on January 29, 2010 at 18:56:50:

Now we may be getting somewhere!I wont dispute welding sky scrapers or a roller coaster might be better done with a 6010 or 6011 root pass covered with 7018.A lot of the reason for that is the mixture of the metal.
If MIG wasnt a lot better for some things I wouldnt have bought one when I already have a 180 AMP Lincoln welder.I would just weld it all with 7018 and 6011.
I bought an H Farmall with a loader.That loader was broke everywhere.Still is in a couple of places.I cut out old welds with a cutter on a grinder that were probably 7018 made by a pro because I could see the flux still on them in places and ground it down to the surface and welded it up with MIG.Then since then I have used for a dozer building 2 foundations for buildings and digging out concrete where a house burned down and not one crack.Also the previous owner had welded a grader blade to the front edge of it and the first time I used it that broke off.He had a nice looking 7018 bead across the front of the bucket with the blade attached to it.Instead of do all the grinding,I just cut the whole weld off at a 45 degree angle and hit it with a grinder and MIG welded it back on veed on one side.No crack anywhere on it and It gets lots of abuse.I took a stump out with it a while back and really put force on it using it for a prybar.
Thats just the last thing I welded on and it was old steel pipe that somebody nearly burned up with welding rods.Ive welded more than one 10 pound spool of wire on it myself fixing cracks and the other stuff.
Ive welded many hours on some old spray rigs.I built the booms out of pipe and back then the people I was working for only had an old buzz box.I welded some real good looking welds on there and they would run about 3 days and all of them would be broke.They thought it was me and hired a different welder and all of his welds broke too.So they went and borrowed a MIG welder from a body shop and welded it up and cut the cracking down a lot.
I went out in the river bottoms on a Sunday one time and this farmer had a great big field cultivator.Big as they made in the 1970s.He had gumbo dirt and a tractor turned way up to pull it and that thing was broke everywhere.I welded on it for a long time with a Pipeliner and 7018 just about all day.The next afternoon he called and it was broke everywhere again.So he brought it to the shop and welded with a MIG and it held.Where it broke the first time was in places that were welded with a stick from the factory.Whatever the square tubing is made out of in farm machinery doesnt like to be welded with stick.
Thats a couple of examples but lots and lots of things Ive welded since then have proved to me that MIG just works better for that stuff.
Even welding with a stick,if you put a big old nasty looking weave weld on something turned up hot and burned in like some people say,will crack before a weld that is no bigger than necessary and preferably uphill welded.Ive been told by highly experienced welders that its because the smaller weld doesnt heat the area up as much and thats why it doesnt crack as easy.Weaving is OK but not very wide.
Even old stuff like my loader will hold up better using a MIG but for sure the newer stuff is made out of some alloy that you cant hardly weld with 7018.
I remember a professional welder fixing a boom on a backhoe with a portable welder and 7018 and it broke in about 2 weeks.The right thing to use on that is deep penetrating flux core wire and it will still crack,but 7018 is almost a waste of time welding it with that.Its just too hot in too big of an area and makes that square tubing crack.That high carbon steel square tubing is a lot different than mild steel plate,pipe,beam,channel you deal with all the time.
Even on the same piece of equipment,depending on the metal and how thick it is,it could be better to weld it with a stick.However to fix cracks and places in thinner metal 1/8 TO 1/2 INCH THICK and especially on square tubing or pipe its better to use a MIG.I also wouldnt bet that because some pieces might be preferred to weld with 7018,it could still be welded and hold just as well because of the less heating up of the surrounding area on even thicker metal done right in multiple passes.
Ive welded structural and even roller coaster parts.If that was all I ever did I wouldnt know about farm machinery.Ive welded truck frames and I prefer 7018 for that.I wouldnt rule out MIG for a truck frame,but 7018 uphill is the way I was taught to do that.Fixing backhoe buckets I was taught to use MIG uphill.
I know there are lots of things welded with 7018 and even 6011 that hold up.If thats all you have you can get by on a lot of stuff.Even how you weld affects how it holds up Ive learned too.I was working on a big truck one day welding a brace that holds the muffler that had been broke more than it was fixed.It was fairly thick pipe about an inch around.I had it off v grooving it and welding it with 7018 because we only had a buzz box then.A guy that welded race car frames walked by and saw what I was doing and told me if I got a piece and bent it over it or another piece of pipe and cut it lengthwise and welded it only longways instead of around it,that it would quit breaking.I got about a 3 inch long piece of black pipe,cut in half lengthways,beat on it until it fit,welded only on the sides lengthways and it wasnt broke a couple of years later when they traded off the truck.
I had a professional stretch a truck for me because I didnt have a welder at the time.He welded the frame with a root pass of 6011 and then 7018 on top.Then he told me to get a sleeve bent to go just around the frame and past the weld about a foot on each end.Also the sleeve didnt go all the way to the edge it was back about a 1/4 from the edge.He took a torch and beveled both ends of it,beat it on with a sledge and clamped it,them MIG welded it skip welding 3 on 6 on both edges,then down just the bevels on the ends.Not across the frame just on the bevels.Hauled some real heavy loads and never had any trouble.The actual sleeve did crack a little in the corners,but no where that it was welded.
I myself have welded on lots of grain trailers and in some places used MIG and in some places used 7018 like on a fifth wheel plate for 7018,cross members MIG.
I have made repairs in the field with 6011 that held better than with 7018 on a combine.6011 seems like it will take bending and twisting in some things better than 7018.I still prefer a MIG,but its not always available or even possible to get one to the piece.
Now Im a fairly good welder and have plenty of problems with 7018.Even have seen where pros could and couldnt fix things,and can say that 7018 is not always the best and strongest way to weld something.It is especially bad for thinner metal like 1/2 in down on newer equipment and also older pipe fabricated stuff.MIG is just all around better for repairs on stuff like farm equipment that has cracked,possibly because it was welded with 7018 to start with.Anybody thats done some of this will tell you the same thing I did and probably have experiences like I do with the same thing.Even a good welder cant get this stuff to hold so how can an amateur who may or may not make a good weld with 7018?
I dont even want to get started on brazing or 6013 or any of that stuff there.However I have seen brazing done by a pro break and then fixed by the same guy with a MIG and hold.I have ground brass off of stuff and welded it with a MIG and it fixed it myself.6013 is worthless for me to use.Im sure some people can but Im not one of them.
Where 7018 works its about as good as there is.But its just highly overrated for a lot of things.Even 6011 can be a better choice sometimes.Static/dynamic argue all you want and get all bent out of shape,but it doesnt matter if the weld breaks.There are other factors you may not even know about yet to consider.Also fixing something is completely different than making something new from scratch.Even how the steel is cut affects how strong it is.The alloy its made of,whether it just sets there or has twisting and vibration and shock load to deal with.Also the amount of heat used on it to fix it and the stress its under when you get done welding it have all kinds of different affects on it.

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• Re: Welding question 135 Fan 11:53:45 01/30/10 (0)

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