Shop Floor Talk  

Go Back   Shop Floor Talk > Welding and Metalworking Forums > Welding

 
 
SFT Search:
Reply
 
Thread Tools Display Modes
  #1  
Old 05-14-2023, 10:25 PM
CaddmannQ's Avatar
CaddmannQ CaddmannQ is offline
Elite Member
 
Join Date: Sep 2021
Location: CenCal
Posts: 2,099
Default Up the Crack or Down?

I have a 1/8” pressed steel shape that has a 1” long crack at an edge. I have drilled a hole at the end of the crack. Now I am going to weld it up.

Should I weld towards the hole, or towards the edge?

This is mild steel and I am going to use the TIG welder.
Reply With Quote
  #2  
Old 05-14-2023, 10:45 PM
Ironman's Avatar
Ironman Ironman is offline
Iron Modification Investigator
 
Join Date: Feb 2008
Location: Warburg, Alberta
Posts: 17,536
Default

I would control warpage by backstitching
__________________
Gerry
You got freedom of speech, if you don't say too much.
Aaron Neville.

When a liberal screams racism, you can bet they were also born with white skin.

Common sense is like deodorant. The people that need it most never use it. Joe Concha
Reply With Quote
  #3  
Old 05-15-2023, 09:40 AM
CaddmannQ's Avatar
CaddmannQ CaddmannQ is offline
Elite Member
 
Join Date: Sep 2021
Location: CenCal
Posts: 2,099
Default

Thank you Ironman.

I won’t try to weld it in a single pass, but I guess I asked the wrong question.

Would you put the first puddle near the edge, or at the hole, or perhaps somewhere in-between?

Since I did not know the best place to start this weld I was going to start in the middle of the crack and jump back-and-forth.

I have total access to weld this from both sides flat on the table.
Reply With Quote
  #4  
Old 05-15-2023, 09:58 AM
astronut's Avatar
astronut astronut is offline
Elite Member
 
Join Date: Jun 2019
Location: Louisiana
Posts: 2,353
Default

I would start the weld at the edge while the piece has not absorbed much heat yet. Less tendacy to melt the edge than if tried it last after absorbing a bunch of heat and wanting to melt the edges away.
__________________
I love the smell of napalm in the morning. It smells like, victory!
Rommel, you magnificent bastard, I read your book!
Still got the shovel!

Victor Torch Set With Meco Regs
Lincoln Weld Pak 100
Giant Tech Arc 200
Miller Roughneck2E
Reply With Quote
  #5  
Old 05-15-2023, 01:09 PM
digr's Avatar
digr digr is online now
The Real Deal
 
Join Date: Apr 2005
Location: Duluth MN
Posts: 9,352
Default

I don't think it really matters.
__________________
Drawing by Smartdraw
Reply With Quote
  #6  
Old 05-15-2023, 02:05 PM
CaddmannQ's Avatar
CaddmannQ CaddmannQ is offline
Elite Member
 
Join Date: Sep 2021
Location: CenCal
Posts: 2,099
Default

It needs a little bit of straightening, and I will wait to do that until after the welding, but I doubt it will have too much warp.

Of course everything depends on my skills as a welder. All things considered, this first little bit of welding should be a breeze compared to what comes later.

But really, I was just curious if there was a general rule about welding up cracks where you have to drill a hole.
Reply With Quote
  #7  
Old 05-15-2023, 08:12 PM
Matt Shade's Avatar
Matt Shade Matt Shade is offline
Made From Scratch
 
Join Date: Jan 2007
Location: Ohio
Posts: 3,665
Default

For flat work on the table I don't think it matters a whole lot. Do whatever is easiest to work at in a comfortable position.

Other variables are more important like the thickness of the material and the position you are welding in etc.

With access to both sides and fairly thin metal if you were in the vertical position it would be ok to weld downhill.

With thicker metal or only having access to one side I would definitely run uphill if I couldn't lay it down flat.

If it is a large gap and the shape of the part is a tight tolerance I would tack a bridge of some sort across the crack if possible before welding it, or at least clamp the hell out of it because the shrinking weld can pull the crack closed and warp your part. Sometimes I will start at the open edge of the crack with some very cold tacks and just stack them until the gap is bridged, then go to the toe of the crack and weld back and burn through the tacks.
__________________
Handcrafted Leather
Reply With Quote
  #8  
Old 05-19-2023, 11:03 PM
CaddmannQ's Avatar
CaddmannQ CaddmannQ is offline
Elite Member
 
Join Date: Sep 2021
Location: CenCal
Posts: 2,099
Default

Well I ended up having to weld several other things first, so this crack business got delayed. With a little luck I will get it welded tomorrow.

I’ve been getting more practice with the TIG welder and I am a lot more confident about how well this will come out.
Reply With Quote
  #9  
Old 05-28-2023, 11:32 PM
CaddmannQ's Avatar
CaddmannQ CaddmannQ is offline
Elite Member
 
Join Date: Sep 2021
Location: CenCal
Posts: 2,099
Default

Just in case any of you are wondering what I finally decided to do,

I finally welded that crack today.

I clamped it down on the anvil to keep it straight, put a good tack weld at the edge, and worked back to the hole.

There was no problem with warpage. It came out straighter than before, which is what I had intended all along.

But I laid it on a little cold, so I back-gouged the weld (with a tiny Dremel Moto tool) and welded it from the back side as well.

Then I ground it out flush, filed it down neatly, hung it up in the air, and banged on it like a bell.

Sounded beautiful. No more cracks.

I clamped it down and hung my weight on it, and the whole rail flexed, but it did not crack. I was real happy about that.
Reply With Quote
  #10  
Old 05-28-2023, 11:38 PM
CaddmannQ's Avatar
CaddmannQ CaddmannQ is offline
Elite Member
 
Join Date: Sep 2021
Location: CenCal
Posts: 2,099
Default

Quote:
Originally Posted by Matt Shade View Post
. . . Sometimes I will start at the open edge of the crack with some very cold tacks and just stack them until the gap is bridged, then go to the toe of the crack and weld back and burn through the tacks.
Except that I welded from both sides this is what I ended up doing. I wasn’t trying to tack it quite as cold as I did, but it worked out great in the end.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Web Search:

All times are GMT -5. The time now is 11:22 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.