When to stitch weld vs solid bead?

[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.