47-55.1 Sheet Metal Console

[Driver_WT]

Originally Posted by BAM55

What you have there is called shrinkage. Welding causes shrinkage sometimes very little sometimes a lot. Thats why we tack weld and take our time when welding sheetmetal. Now you have a HAZ (Heat Affected Zone) when welding its the area where the metal change color in and around the weld. That is the area causing the shrinkage. To fix this I would hammer on dolly. Since you have access to the back I grind both sides of the weld, place my dolly over the front of the HAZ and hammer from the back. Hammer on dolly is stretching the metal so you are trying correct the shrinkage. Experience panel bumpers can do this by placing the dolly on the back of the panel but its easier for a beginner to do the reverse.You can use a guide coat on the bare metal to see how close you are getting. Many cases you will not have access to hammer on the back of panel and thats when you will truly need to learn hammering on and off dolly. Oh and your dolly should closely match the shape of your panel. Do not beat the heck out of it trying to get it to move it takes patience.

Its hard to explain but I hope I helped.

Great information thank you. I will be working on this today and will post results.

[BAM55]

Originally Posted by Driver_WT

Great information thank you. I will be working on this today and will post results.

I forgot to say. Only work the HAZ area (Heat Affected Zone) do not work anywhere else. Once the HAZ is the area that changed color during welding in and around the weld. If there is shrinkage in other areas its still caused by the HAZ area.

[dsraven]

yup, shrinkage from welding is my guess too. like Bam says, hammer on dolly ONLY the haz to expand that area. I use a piece of sandpaper on a block of wood to scuff over the area after making it all colored with a big fatty marker. the sandpaper will show up the high and low spots where a little more work is needed. after that I use a shrinking disc to heat up only the high spots and then a cool wet rag quickly to cool off those heated up spots to shrink then like the metal around them. you could try a laundry iron for that if you get brave. it is only for the last minute final stuff so you don't have to use a bunch of filler.
if doing something like this again, use tack welds and let cool between them. tack, hammer on dolly that tack when still hot, cool, next tack, hammer on dolly the tack, cool, keep going till there is no space between the tacks. space the tacks out to hold the piece in shape so the gap stays consistent along the whole edge. like do one at each end, one in the middle etc, before doing a bunch like in the middle or something. don't start in the middle and work your way out unless you are carefull to keep an eye on the overall shape and gap spacing. otherwise you will find the piece has slowly found it's way into the scrap pile because it is outta shape. always let it cool off till you would be comfortable sticking your tongue on it before tacking/welding again (thanks martinsr for that tip, lol). having two projects to do at the same time is good so you aren't tempted to go too fast.
since the project is supposed to be flat across from side to side, you could hammer on dolly from the back side using something fat like a steel workbench top or a piece of flat steel as the dolly. be aware of what type of crown your body hammer hammer has as well. a little research will help figure that out, or trial and error. if you have a dolly that is shaped like the curve you can use it as a hammer/slapper.