When to stitch weld vs solid bead?

[Haywire]

Title says it all. When do you stitch?

Ian

 

[odleo]

I use a stitch weld to.avoid distortion.of.thin metals. Everything else I do solid

 

[deereman75]

I stiched the top on my welding table. It is 1/4 inch plate, and it still warped a little bit.

 

[MikeD74T]

Continuous weld when a seal in needed, enough stitches when strength only is needed. Sometimes they amount to the same thing. Long welds can promote unnecessary warping. MikeD74T

 

[Shield Arc]

I generally use skip welds with anything that is going to have a ripping effect. Once a cracks starts it can rip right through a continuous weld, but it is sometimes harder for the crack to start in a new weld.

Distortion is another good reason, plus back stepping any welding to help with distortion.

 

[Haywire]

back stepping

What's that? Is that staggering the stitches side to side like this? _¯_¯_¯_

 

[Shield Arc]

What's that? Is that staggering the stitches side to side like this? _ｯ_ｯ_ｯ_

Back stepping is one of the most important techniques you need to know to be a top notch weldor. You have to plan out your welding before you ever start, you can't just drop your hood, and start pouring wire / rod. Or you'll end up with a big mess!
This is back stepping and skipping around. Two very important things to do, to counter warping.

 

[Haywire]

Ah, ok... I'm off to the shop to warp up some metal. LOL

thanks

 

[Shield Arc]

Maybe this is a better illustration of what I'm trying to say. I left a little gap between welds on purpose.
Welding vertical up will really get hot at the top of the plate if you start at the bottom and weld all the way to the top. Back stepping breaks up the heat line. I back step everything I weld, but I also try to skip around a lot too!

 

[Mercmaniac]

Hey Shield Arc, Thanks for the diagrams you posted. As a beginner welder this is of great help. I just completed a bracket to bolt to my ballast box for a 2 " receiver (grnspot110's patent ) and did have some distortion issues. Nothing that would affect anything but something I notiiced and want to be able to correct in the future.

 

[Shield Arc]

You're welcome Mercmaniac! Remember there is more to this puzzle.
In most cases you're better off to heat shrink before welding. Say you wanted to weld these 4 risers to this pipe. If you make even one of these welds much less all four, the pipe is going to curl upwards big time! So you want to heat shrink on the opposite side of the weld zone before welding.

 

[cub]

You're welcome Mercmaniac! Remember there is more to this puzzle.
In most cases you're better off to heat shrink before welding. Say you wanted to weld these 4 risers to this pipe. If you make even one of these welds much less all four, the pipe is going to curl upwards big time! So you want to heat shrink on the opposite side of the weld zone before welding.

Hi, we sometimes weld a bead inside the bottom of the pipe through the cut out opening BEFORE welding the outlet pipe or thread-o-let on depending on size.

 

[Shield Arc]

Hi, we sometimes weld a bead inside the bottom of the pipe through the cut out opening BEFORE welding the outlet pipe or thread-o-let on depending on size.

Wouldn't that cause turbulence in the flow?

 

[Haywire]

All done, I bet it's warped to beat the band, but hopefully the stitching kept it to a minimum. I was welding 2x24 strips of 1/2" plate in a T orientation to the bottom of my welding table top. They connect the two halves of the table top, leaving a 1 5/8" gap down the middle to allow clamping in the middle of the table. Got that idea here someplace.

Ian

 

[Tractor Seabee]

You're welcome Mercmaniac! Remember there is more to this puzzle.
In most cases you're better off to heat shrink before welding. Say you wanted to weld these 4 risers to this pipe. If you make even one of these welds much less all four, the pipe is going to curl upwards big time! So you want to heat shrink on the opposite side of the weld zone before welding.

Shield,

One of the tricks we used to do was tack a piece of channel on edge on the under side, then drive a wedge in the center of the branches with 1/2" gap to put reverse tension in the cold side. On pipe we did that after cutting the holes. WE did a lot of step welding to keep the heat down. Usually required a lot less spot heating to get it back straight.

Ron

 

[cub]

Wouldn't that cause turbulence in the flow?[/QUOTE

Don't think turbulence is a issue. Run Hot no real weld build up. This was only on chilled and hot water piping , not critical ASME code work. Actually some of the s$%ty pipe we got there was more restriction from the seam ! Most cases we use tees, does a professional job although some engineers would allow you to saddle up to half the diameter. Hard to make it look good.

 

[Shield Arc]

Shield,

One of the tricks we used to do was tack a piece of channel on edge on the under side, then drive a wedge in the center of the branches with 1/2" gap to put reverse tension in the cold side. On pipe we did that after cutting the holes. WE did a lot of step welding to keep the heat down. Usually required a lot less spot heating to get it back straight.

Ron

I thought arc strikes outside the weld zone were forbidden in your line of work?:confused2:

Wouldn't that cause turbulence in the flow?[/QUOTE

Don't think turbulence is a issue. Run Hot no real weld build up. This was only on chilled and hot water piping , not critical ASME code work. Actually some of the s$%ty pipe we got there was more restriction from the seam ! Most cases we use tees, does a professional job although some engineers would allow you to saddle up to half the diameter. Hard to make it look good.

I don't know anything about pipe work, but always willing to learn. Thank you!
Seems as the inspectors are always busting guys out for having too much penetration on their root pass.

 

[Tractor Seabee]

I thought arc strikes outside the weld zone were forbidden in your line of work?:confused2:

I don't know anything about pipe work, but always willing to learn. Thank you!
Seems as the inspectors are always busting guys out for having too much penetration on their root pass.

Shield, only on ASME stamped work. There we clamped the strong back on, usually two vise stands. The biggest problem for this is smaller pipe. Larger the pipe or structrual material the less problem. Saddles like mentioned are only allowed at 1/2 the pipe diameter for the branch. Tees are required after that.

Ron

 

[rjmack]

far as stitching structural steel, there are times to stagger the stitches, and times to oppose them.

this is a very comprehensive book [ame=http://www.amazon.ca/Modern-Welding-Andrew-D-Althouse/dp/1566379873]Modern Welding: Amazon.ca: Andrew D. Althouse: Books[/ame]



i don't do much pipe work at home, but it is certainly possible to weld on one side of a member and keep it straight. this rake rack was tacked to the table and welded before the upright was installed.