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Angle iron miter mig welding

Posted: Wed Apr 26, 2017 1:30 pm
by Josh MacD
I'm a new welder but I have a project I'm working towards. I want to use angle iron and steel mesh to create some gabion structures. I plan to use 1.5 x 1.5 x 1/8th inch angle iron with 3" steel mesh.

When creating 90 degree corners I've seen the miter versus cope debate on this and other forums. With smaller angle iron the coping might be more work than is necessary. But... I'm not sure I can weld the outer 'knife edge' of the miter without either creating a ton of extra grinding work or burning through the edges and making it look like poo. Any suggestions on welding that miter (assuming that's the better joint option)? Oh, and I'll be making an x-y-z joint with a third piece that I plan to weld to the interior of the miter so I don't want a bead crowding my space on the inside of the miter.

Thanks in advance.

Re: Angle iron miter mig welding

Posted: Wed Apr 26, 2017 3:26 pm
by Louie1961
I have coped all of my recent projects. Coping is a LOT easier if you use a vertical bandsaw: either a portaband in a stand or something like a Harbor Freight 4x6 in the vertical position. Here's some pics of a cart I made for my welder and a small welding table I put together using coped joints. Coping worked out OK for me.
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Re: Angle iron miter mig welding

Posted: Wed Apr 26, 2017 3:48 pm
by Josh MacD
The only bandsaw I have is a table top woodworking version. I'm not sure if I can put in a metal blade and use it for this purpose. I'm cutting with either a grinder (7 or 4.5") or chop saw (not exactly an accuracy tool). I've seen someone cope with a hand held jig saw but I can see that costing a fortune in blades with as many cuts as I need to make.

Re: Angle iron miter mig welding

Posted: Wed Apr 26, 2017 3:53 pm
by exnailpounder
Josh MacD wrote:The only bandsaw I have is a table top woodworking version. I'm not sure if I can put in a metal blade and use it for this purpose. I'm cutting with either a grinder (7 or 4.5") or chop saw (not exactly an accuracy tool). I've seen someone cope with a hand held jig saw but I can see that costing a fortune in blades with as many cuts as I need to make.
I cope every corner. The more weld you can get on something, the stronger it is. If you have a grinder, get a cut-off wheel for it to cope with or you can free hand cope with a chopsaw ...just wear safety glasses and stay off to the side of the wheel. Mitering looks amateurish.

Re: Angle iron miter mig welding

Posted: Wed Apr 26, 2017 3:58 pm
by Josh MacD
exnailpounder wrote: Mitering looks amateurish.
As a lifelong woodworker that runs against everything I know, but I'm still learning the rules around here.

Re: Angle iron miter mig welding

Posted: Wed Apr 26, 2017 4:22 pm
by exnailpounder
Josh MacD wrote:
exnailpounder wrote: Mitering looks amateurish.
As a lifelong woodworker that runs against everything I know, but I'm still learning the rules around here.
I used to woodwork some myself (and carpenter work..hence my screen name) and mitering is customary in that profession but in metal, the idea is usually to make something as strong as possible. You can get much more weld bead on a coped angle or box tubing than you can mitering. Strength might not be a priority for your project but IMO every project should be as strong as it can be made. I also happen to think coped looks better.

Re: Angle iron miter mig welding

Posted: Wed Apr 26, 2017 7:07 pm
by PeteM
Just hit the outside corner with a hot and quick down pass and weld the joint all around.

That'll give you some practice reaching in and around to get all of the nooks and crannies.

Re: Angle iron miter mig welding

Posted: Wed Apr 26, 2017 8:22 pm
by Louie1961
You should consider buying a portable band saw. They are really indispensable for cutting stock to be welded. You can easily build or buy a stand to use them in the vertical position. I even saw one guy who bought soft vise jaws and just chucked his portaband up in the vise. The best ones are Milwaukee, but I couldn't resist picking up the harbor freight portaband when it was on sale for $99. You can also find good used Milwaukee and Dewalt portabands on Craig's List for around $100 sometimes.

Re: Angle iron miter mig welding

Posted: Thu Apr 27, 2017 12:02 am
by Josh MacD
I've heard the harbor freight version is one of the few redeeming tools there and worth the $. But I've already sunk a bit more than expected into this process. The Long Haired General may balk at another $100.

Re: Angle iron miter mig welding

Posted: Thu Apr 27, 2017 4:05 pm
by Louie1961
Well you can cut copes with just about anything. I have done it with angle grinders and cutting disks, reciprocating saw (not easy to keep it straight), even a hack saw. The portaband will just save you a lot of time. It is one of those "how did I ever live without this" kind of tools.

Re: Angle iron miter mig welding

Posted: Thu Apr 27, 2017 6:00 pm
by airrj
I have built around 15 different stands out of 1" or 1.5" 11gauge angle and I have done both coped and mitered, and for the strength of the 11 gauge (1/8") material I don't find that the extra time to cope the material is worth it. I use a carbide chop saw to miter the corners. On the horizontal side of the angle I normally weld on the outside, just add a bevel about 80% the thickness of the material and fill with the weld bead. This makes a clean full penetration weld that you can quickly and easily grind flat. For the vertical portion, if there isn't anything that needs to fit right into the corner (not the case for you) I just run a bead up the inside corner. If I have something tight fitting to the inside, I will either leave a 1/16" gap or put a small chamfer on those edges as well and run the bead up the outside, which will again be easy to clean up.

As is mentioned before, I believe that the cope typically is a stronger joint, but in you configuration with the size material that you have I don't see a real advantage to the extra time and effort.

Good Luck with the project.
R.J.

Re: Angle iron miter mig welding

Posted: Thu Apr 27, 2017 11:18 pm
by Josh MacD
airrj wrote:I have built around 15 different stands out of 1" or 1.5" 11gauge angle and I have done both coped and mitered, and for the strength of the 11 gauge (1/8") material I don't find that the extra time to cope the material is worth it. I use a carbide chop saw to miter the corners. On the horizontal side of the angle I normally weld on the outside, just add a bevel about 80% the thickness of the material and fill with the weld bead. This makes a clean full penetration weld that you can quickly and easily grind flat. For the vertical portion, if there isn't anything that needs to fit right into the corner (not the case for you) I just run a bead up the inside corner. If I have something tight fitting to the inside, I will either leave a 1/16" gap or put a small chamfer on those edges as well and run the bead up the outside, which will again be easy to clean up.

As is mentioned before, I believe that the cope typically is a stronger joint, but in you configuration with the size material that you have I don't see a real advantage to the extra time and effort.

Good Luck with the project.
R.J.
That's what I was thinking. I'm all for "over engineering" but an extra 5 min per cut on a non structural piece seemed like overkill. I'll definitely practice some cuts and welds on scrap first but thank you to everyone for the great input.

Re: Angle iron miter mig welding

Posted: Thu Apr 27, 2017 11:26 pm
by Olivero
I miter just about anything I build... Probably would be easier to cope it but I think mitered looks much better.

Re: Angle iron miter mig welding

Posted: Fri Apr 28, 2017 3:04 am
by jrporter
airrj wrote:... just add a bevel about 80% the thickness of the material and fill with the weld bead. This makes a clean full penetration weld that you can quickly and easily grind flat.
I recently built a stand for my band saw, and decided on doing miters. I built a small test piece, and after cutting the miters I ground the sharp edges like recommended above which gave a nice area to fill with weld.

Re: Angle iron miter mig welding

Posted: Tue May 02, 2017 9:24 am
by AdVirMachina
exnailpounder wrote:
Josh MacD wrote:
exnailpounder wrote: Mitering looks amateurish.
As a lifelong woodworker that runs against everything I know, but I'm still learning the rules around here.
I used to woodwork some myself (and carpenter work..hence my screen name) and mitering is customary in that profession but in metal, the idea is usually to make something as strong as possible. You can get much more weld bead on a coped angle or box tubing than you can mitering. Strength might not be a priority for your project but IMO every project should be as strong as it can be made. I also happen to think coped looks better.
How do you cope a square tube? I'm not seeing how that would work.

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Re: Angle iron miter mig welding

Posted: Tue May 02, 2017 10:18 pm
by Otto Nobedder
AdVirMachina wrote: How do you cope a square tube? I'm not seeing how that would work.

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Coping square tube is rare; The nature of square tubing reduces the benefit of coping over a miter unless the loading is through torque. The time involved in properly coping square (or rectangular) tube is significant, as well.

I attempted to draw a square tube cope profile, but I've had too much food and way too much beer to pull it off. I'll attempt it again tomorrow right after work, if no one beats me to it.

Steve

Re: Angle iron miter mig welding

Posted: Tue May 02, 2017 11:52 pm
by airrj
AdVirMachina wrote:How do you cope a square tube? I'm not seeing how that would work.
Checkout the photos in Post #2 of this thread by Louis1961. He shows some coped joints.

Re: Angle iron miter mig welding

Posted: Wed May 03, 2017 8:45 am
by exnailpounder
Otto Nobedder wrote:
AdVirMachina wrote: How do you cope a square tube? I'm not seeing how that would work.

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Coping square tube is rare; The nature of square tubing reduces the benefit of coping over a miter unless the loading is through torque. The time involved in properly coping square (or rectangular) tube is significant, as well.

I attempted to draw a square tube cope profile, but I've had too much food and way too much beer to pull it off. I'll attempt it again tomorrow right after work, if no one beats me to it.

Steve
I can make a cope on box tube or angle in 30 seconds with my porta-band. I've seen guys try to use a chop saw to miter and when that blade gets flexing it might be a 45..or not. My cold saw works great for mitering but at $100 a blade, I save it for more important cuts. I bet I can cope a piece as fast as anyone can miter one. The porta-band RULES!
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This is the corner of my patio table that I made. I weld the outside corner, the inside corners and the butt and left the top unwelded and it looks clean except for that tiny blade overrun :oops: . I guess I could have full welded it and then ground the welds off flush but it doesn't make sense to weld something and then grind it off some times. Grinding time and wheels are money.

Re: Angle iron miter mig welding

Posted: Wed May 03, 2017 11:29 pm
by Otto Nobedder
Thanks to Jeff, I don't have to draw it. That's an excellent example. One time-consuming variation (which I had in mind when calling the task time-consuming) is to do the reverse side opposite the face side, so the butt is vertical, where on the face side it's horizontal. This further breaks up the relationship between loads and welds, but is likely overkill for most purposes. It is no longer just a band-saw job, at that point.

Steve

Re: Angle iron miter mig welding

Posted: Thu May 04, 2017 10:02 am
by AdVirMachina
Thanks! It is very clear now.

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Re: Angle iron miter mig welding

Posted: Fri May 05, 2017 8:57 am
by exnailpounder
Otto Nobedder wrote:Thanks to Jeff, I don't have to draw it. That's an excellent example. One time-consuming variation (which I had in mind when calling the task time-consuming) is to do the reverse side opposite the face side, so the butt is vertical, where on the face side it's horizontal. This further breaks up the relationship between loads and welds, but is likely overkill for most purposes. It is no longer just a band-saw job, at that point.

Steve
Yeah Steve the band saw is just so quick that it doesn't really add any appreciable time to a build and it looks good and it stronger than a miter. I have taken some good natured grief for "over building" things and I always come back with " if I didn't want it to be strong, I would have used balsa wood and Saran Wrap" If I get a chance, I will run over to the fast lube center the next town over and take a few pics of the hanging catwalks I built many moons ago. Everything is coped and neatly welded...my partner and I were always commended for how slick our work was. I miss those days.

Re: Angle iron miter mig welding

Posted: Fri May 05, 2017 6:54 pm
by Otto Nobedder
exnailpounder wrote:
Otto Nobedder wrote:Thanks to Jeff, I don't have to draw it. That's an excellent example. One time-consuming variation (which I had in mind when calling the task time-consuming) is to do the reverse side opposite the face side, so the butt is vertical, where on the face side it's horizontal. This further breaks up the relationship between loads and welds, but is likely overkill for most purposes. It is no longer just a band-saw job, at that point.

Steve
Yeah Steve the band saw is just so quick that it doesn't really add any appreciable time to a build and it looks good and it stronger than a miter. I have taken some good natured grief for "over building" things and I always come back with " if I didn't want it to be strong, I would have used balsa wood and Saran Wrap" If I get a chance, I will run over to the fast lube center the next town over and take a few pics of the hanging catwalks I built many moons ago. Everything is coped and neatly welded...my partner and I were always commended for how slick our work was. I miss those days.
I'll have to dig up some pictures of my own. Not related directly to the topic, but to "attention to detail". At an ethanol plant in Iowa, we were building gas trains for the distiller's grain dryers. I did all the fitting, and my partner and I shared the welding. Our meth-head boss was always on us to move quicker... Until the biggest bosshole Fagen ever hired, the pipe foreman for the site (who looked at our little twelve man crew of misfits like something he'd scrape off his shoe) actually complemented us on how professional our work looked.

The Meth-head boss would come try to push us now and again, but had lost his magic.

Steve

Re: Angle iron miter mig welding

Posted: Thu Jul 27, 2017 6:16 am
by Clifford_Pierce
Use angle grinder.it's your best option.

Re: Angle iron miter mig welding

Posted: Thu Jul 27, 2017 9:24 pm
by homeboy
I have the 41/2in Dewalt and the Milwaukee Fuel with paddle switch and they make a great pair. The Dewalt with a 30-40 grit flap disk has the power to hog material fast and the Milwaukee is handy for the lighter stuff,dressing up etc. Don't expect a 5amh battery to wear you out but with a spare or two it will do a lot of work. :D :geek: