First time (MIG) welder - Warped panel fix question

More of an art than a science - discuss metalworking and welding here.



Non-Lurker
Posts: 6
Joined: Tue Aug 26, 2014 8:01 am

Country:
USA
PostPosted: Thu Aug 28, 2014 10:25 pm
Hello All,

Today I attempted my first welding patch :D It may not be the best job and the welds are far from good, but its my first time and Im proud of myself!

Unfortunately, all is not well. I made 2 or 3 small "tack" welds across from one another and then let it sit for 5 mins or so then did 2 or 3 more until the whole patch was welded in. I went slow and always felt the area before to make sure it wasn't hot to the touch. Unfortunately the bottom portion warped :(

I looked online and saw different techniques on how to fix this. Dolly and hammer, shrinking disk, heating up a red hot spot in the middle and then spraying water on it, etc. Another way I read up on was to re heat the bottom welds (closest to the warp) and then hammer out the red hot weld with a hammer and dolly.

I am a bit confused on which method I should do and what is causing the warp. I think the weld might actually be holding that section "low" but I do not know. I can feel the warp and see it when the light hits it just right. Should I just not worry about it and slap some Evercoat gold filler over it and the weld area once ground down?

I attached some pictures below (please be easy on the weld quality, I know it sucks)

(You can see the outline ring where the metal is showing. I took a block and sandpaper and just sanded back and forth to show the low spot in the middle. The metal showing around the weld was sanded down prior to welding.)
Image


Image


(This is a picture of the back side. the top of the photo are the welds closest to the warp.)
Image


Thanks a lot for your alls help!



No Turning Back
Posts: 977
Joined: Mon Jun 20, 2011 3:58 pm
PostPosted: Fri Aug 29, 2014 6:58 am
You would need to grind the weld bead down close but not all the way level with the panel on both sides, front and back. Do not heat it, just work it cold. Use a dolly that fits the shape of the panel it is laying against, and apply firm pressure as you strike the weld with a body hammer.

Be sure you are applying more force with the dolly than with the hammer blows, otherwise you will be moving metal instead of stretching. Do all your work on the weld only. Practice a little with some scrap metal to be sure you don't dent the metal with the edge of the hammer face. Watch closely that you don't stretch it too much, if you do it right it may stretch quicker than you expect.



Non-Lurker
Posts: 6
Joined: Tue Aug 26, 2014 8:01 am

Country:
USA
PostPosted: Fri Aug 29, 2014 7:59 am
Thanks for the reply! Just to make sure I understand everything right, after I grind down the welds almost all the way ill use a hammer and dolly. Put the dolly on the backside of the fender and hammer the weld (closest to the warp) from the front side of the fender. Do I just really need to hammer the weld or go around? Sorry trying to learn everything as I go.

Thanks for your help!



No Turning Back
Posts: 977
Joined: Mon Jun 20, 2011 3:58 pm
PostPosted: Fri Aug 29, 2014 8:44 am
Hammer the weld only, but not just what is closest to the problem, hammer all the weld. You may have to hammer more on the closest area later. The edge of the panel helps control the side closest to it, but that shrinks also. Your problems are coming from the weld, so do all your work on the weld. Its common to want to attack the buckles, but that only causes more problems.



Non-Lurker
Posts: 6
Joined: Tue Aug 26, 2014 8:01 am

Country:
USA
PostPosted: Fri Aug 29, 2014 10:30 am
chevman wrote:Hammer the weld only, but not just what is closest to the problem, hammer all the weld. You may have to hammer more on the closest area later. The edge of the panel helps control the side closest to it, but that shrinks also. Your problems are coming from the weld, so do all your work on the weld. Its common to want to attack the buckles, but that only causes more problems.


Thanks a bunch for all of your help, I really appreciate it! Ill post my results.



Fully Engaged
Posts: 166
Joined: Sat Sep 04, 2010 8:22 am
PostPosted: Sat Aug 30, 2014 12:16 am
one trick to help cool your welds is to have your blow gun with the air pressure cranked way up, right next to you so as soon as your finished welding, give the weld a long blast of air



* Banned *
Posts: 496
Joined: Sun Dec 02, 2012 11:33 pm

Country:
USA
PostPosted: Sat Aug 30, 2014 7:20 am
The weld needs to be ground flat with the surface for proper H&D work, not left proud. Another reason is if a shrinking disc was needed, it would be inneffective if welds were not ground flat . The weld and the HAZ area (Heat Affected Zone) need to be stretched. Heat shrinks metal, the surrounding area distorted because it was drawn toward the weld. Welds should not be cooled during welding. Shrunken metal needs to be stretched.

It appears you also welded the backside which is incorrect. Practice to achieve full penetration from one side. Buttwelds should have zero gap. If you want to increase your knowledge go to the Metalmeet site. A lot more pros there than on a hobby site.

User avatar

Settled In
Posts: 83
Joined: Sun Dec 26, 2010 12:48 am
PostPosted: Tue Oct 14, 2014 11:47 am
ScottB wrote:The weld needs to be ground flat with the surface for proper H&D work, not left proud. Another reason is if a shrinking disc was needed, it would be inneffective if welds were not ground flat . The weld and the HAZ area (Heat Affected Zone) need to be stretched. Heat shrinks metal, the surrounding area distorted because it was drawn toward the weld. Welds should not be cooled during welding. Shrunken metal needs to be stretched.

It appears you also welded the backside which is incorrect. Practice to achieve full penetration from one side. Buttwelds should have zero gap. If you want to increase your knowledge go to the Metalmeet site. A lot more pros there than on a hobby site.


Excellent advice!!!!



Fully Engaged
Posts: 285
Joined: Wed Mar 12, 2014 12:09 pm
Location: Buffalo NY
Country:
USA
PostPosted: Tue Oct 14, 2014 9:37 pm
That's probably why it shrank only on one of my areas that I welded, since I was bridging/filling a gap, I used my air gun to cool the area since I figured it was getting hotter since I was actually filling small gaps and holding the trigger longer.

Return to Welding & Metal Fab

Who is online

Users browsing this forum: No registered users and 46 guests