Some one in the trucks past just jammed body filler in to the rust hole. I cut it out and welded in new metal.

 

Look in my gallery under "top cutz" some of those photos show the seams welded up. Hope it helps

 

It's not necessary as far as I'm concerned to completely weld the seam shut. You can just stitch weld and fill the rest. If you were to just fill a seam without welding at least part of it, flex in the body over time will crack the filler. I did however completely weld my seams closed over a couple days. It's really your choice.

 

Thanks Mervy, looks great!

 

I think welding the entire seam shut is a good idea. I know the metal will be thicker in that area and thats why Im paranoid about ghosting after the final finish is on. Different rates of contracting in the seam verses the sheet metal being joined by the seam. Some feel this will cause ghosting in extreme tempretures.

 

I don't think you will ever see it unless it's been parked outside at -40° and then bring it in a heated garage...

 

Did you leave the backer in when you welded the seam

 

Schoo, not sure what your referring to, but "backer can mean two things". Backer is normally a piece of copper or aluminum that is held temporarily behind a weld to absorb heat while the weld is being applied. If its copper or aluminum, it will not stick to the weld seam. That is the reason it is temporarily held in place with clamps. A "backer" can also be a piece of sheet metal that completely covers the weld seam from behind. It is cut to lap the joint from behind, then plug welded on one side to the back of the first piece of sheet metal. Once plug welded, the second piece of sheet metal being joined is butted up to the first piece and butt welded together over the "backer strip". That kind of backer strip is permanently welded into the seam. It is a rust trap in my opinion. "Backers or heat sinks are more for butt welding two pieces of sheet metal together where there is no flange behind a seam, just butt welding two pieces of sheet metal together. I am not sure how either backer strip could be used in filling factory seams becasue factory seams I am familiar with all have a "flange" which would not allow either method of "backer strip" to be held behind the seam. Hope that makes sense.

 

copper makes an excelent backer, but one tip, don't get it red hot cause then the copper will fuse to the weld. Use the thickest chunk you can find to lessen the chance of that happening, for your spots you should be ok.
Don't let anyone tell you it won't stick I've been useing that for years and I did get careless once and stuck to my backer on a plate fill and redrill in a steel mill, got in to much of a hurry to finish the fix.
Joe

 

I blasted and ground the flanges shiny. The inner flanges have to stay in because the mounting bracket bolts to it. As you can see in the top pic, the match between the the two parts is not very attractive with that gaping crack. I spent a whole bunch of time trying to get a good matching tight fit hammering and heating but in the end I said to my self " to heck with that" and welded them together. The other side turned out good, so I think I'll be happier with the smooth look.

 

Thanks for that tip custom, I never heard of copper sticking to the weld but I believe what your saying.

 

Mervy, another option is to lay a piece of welding wire in the gap and weld over the top of it. I have done that and it helps fill the void, but I have yet to paint it so I dont know if there will or will not be a ghosting problem in the paint.

 

Why are you worrying so much about ghost lines?

 

I have been told by numerous forum members that if you have two different thicknesses of sheet metal you risk ghost lines. Different thickness metal expands and contracts at different rates, causing ghost lines in the seam where the metal is joined together by other means than butt welding. The problem seems to be very common with the use of panel bonding. Fusor makes a seam sealer that is designed to minimize or eliminate ghosting, however that is panel bonding adhesive and not lap welding. My point is, fusor makes a product that advertises getting rid of ghost lines when lapping sheet metal and using panel bond. When I think of all the vehicles that had over lapped seams covered with lead (from the factory), I never saw or heard of ghost lines. Now paint and body forums (SPI and Autobodystore.com) are full of threads warning of ghost lines when lapwelding sheet metal. I guess Im concerned about putting all the work into a project and then having it ghost on me.