I just cut out a patch that I did on my left fender. I orignially patched it and did not like the repair. Too much warpage and didn't look good. Well, this time I did a better job but there is an area that I can't get level. Hopeing someone has a recommendation.

You can see in this pic most of the patch is level and smooth. However, there is a spot in the middle of that patch where you can see the welds cannot be ground flush without taking off a lot of material. I was able to hammer on dolly on most of the spot welds, but have not ground the backside of patch.

Should I hammer from the backside with hammer on the dolly? or should i fill it with a little more MIG spots and then hammer on dolly?

http://img184.imageshack.us/img184/357/img5601ht8.jpg

Are you able to get to that area? Or is it blocked by the brace?

I think the problem is the welder, don't you have a hobart, probably can't get enough current out of it.

I'll crate this miller up and send it down.:p

Rob

You can ink the area with a sharpie marker and block sand it. This will tell you what you need to do. Any high and low spots still in the metal.

If you put a straight edge over the weld seem does it show light? If you can see light the area is still shrunk and needs more stretching. Using the hammer ON dolly on the weld seem will stretch out your metal. You will use the dolly on the backside and hammer from the outside. This will stretch out that metal making it raise up.


ONLY WORK THE HAZ!!! This is the ONLY thing that changed do NOT work outside the HAZ.

It looks like you just undercut the metal. Meaning your weld was very hot and burned away the edge. You cant fix that without adding more weld and thus adding more heat. Try turning down the heat or volts down a tad.
Personally if the repair is level and smooth just add a tad of body filler and forget about it.
You will never get that seem invisible unless you grind the crap out of it making it thin or add more weld and rework the area.

boy that looks crappy. you need to just throw the whole car away and start over :)

ssboy, I was just thinkin, you ought to take that hobart and team that up with Andy and his stickin lincoln, maybe you two could get enough ooomph out of it to penetrate that saran wrap metal you have.:D

If you cant get that dolly on the backside you can use something like this. Althou the one shown in the pic is made by Martin you can make one out of a leaf spring.

Long pry tool on far left of photo. Another great shape is the one right below the body hammer, probably my favorite.
http://www.imagestation.com/picture/sraid211/p8496e9c205a86922a85774ed0177ca8c/ed87cb36.jpg

And looking at your picture again and seeing how the grinder marks kinda skip over the weld in the middle tells me you still need to stretch that area out. Hitting hammer and dolly will stretch it out raising the metal up...Eric

On a side note if you find yourself needing to shrink some metal you can take your grinder and shrink that metal. Just make sure that your disc is VERY VERY DULL. You wont have the control of a shrinking disc but you will have the ability to shrink.

Todd, Can't get to the backside, the brace is in the way.

Thanks Eric, I think you were the only one that provided 'real' advice here. I'll try hammering on the dolly and see what that does. Thanks again....

Andy... you are are funny. That gave me a good laugh. Same with you Rob, keep the wise cracks coming. How are the shotgun holes in the floor pans?

To the untrained eye that looks like a good repair,can someone tell me what is wrong with that area as I'll be making similar repairs soon.I need to put in a lower patch panel behind rear of tire.
Also what does HAZ stand for?

HAZ - Heat Affected Zone, it's where the heat from the welding has warped the metal, when you weld, you'll notice that there is a discolored area, this is the HAZ.

THe problem he is having, he can not get the weld on the mid-rear portion of the fender flat. He is having trouble hammering out the HAZ metal to make it flat.

-Todd

To add on what Todd said when you weld metal it shrinks in the HAZ. This shrinkage is what causes your warpage. Using a hammer and dolly will stretch out that metal removing your warpage, thus removing the need for body filler or greatly reducing its usage.

When you put in that patch you will notice that some surrounding metal has been sucked it. Since the only thing that has changed is the HAZ that is the only thing you want to work. You dont want to work the surrounding metal that has been sucked in. Work the HAZ and the sucked in metal will disappear.