Calling metal masters

[Bigdav160]

I've installed a dozen patches and painted a dozen cars in my life so I am not a complete newbie but this is the first time I have had to piece multiple patches together instead of replacing a complete panel.

The first piece I installed was the rear lower rear quarter. Not real happy. Fit was OK, the rear looks good but I decided to use the entire patch and splice where the horizontal member is under the panel instead of where the lower molding would go. GM had spot welded the quarter panel to this horizontal piece. Tig welding the seam left me with no way the planish the weld and a slightly puckered look. In front of the wheel well there was bondo from a dent at the belt molding area. After removing that metal I discovered another horizontal piece and, not having much of a choice, cut the patch to that line. Now the question. I want to do as little welding in the concave area as possible. I am thinking of seaming the patch at the red line. The middle piece, I'm looking for advice where the best area is to seam would be. I drew some read lines just as possible locations with no reason why.

[sevt_chevelle]

IMO, with just a quick glance, if you haven't welded in the front piece why not join the front piece and middle together first then weld that combined piece to the truck? That why you can address any welding issues/ warpage.

Since you have rust in the inner wheel well, why not remove enough of that to give you enough room to planish the welds from the outside skin? Then weld in your patch for the inner.

[MP&C]

In addition to Eric's comments, I think your weld at the rear area is too far from the crease, it is up into a flat area that doesn't do well in holding panel shape.




I'd suggest that any weld seam in a job like you're doing would be best located by either a body crease or high crown area at the top (yellow lines).. While not ideal, the "valley" shown by my red line both gives you consistency in width to the crease for helping to hold panel from distorting, and is closer to that crease and farther out of the flat area that is going to distort.





in this cross section view, the weld seam down through the valley will tend to shrink which will pull the panel outward (green line) The benefit here is that while planishing to stretch this area, the hammer action from the outside is also more likely to persuade the panel back inward to its original location once enough stretch has occurred.

[Bigdav160]

So you're saying the concave (green line) is the best place to splice?

[Bigdav160]

Since you have rust in the inner wheel well, why not remove enough of that to give you enough room to planish the welds from the outside skin? Then weld in your patch for the inner.

I'll have to look. Is the wheel house bolted in a Suburban? It does need a little repair. I'm not anxious to cut it out and have to weld overhead to replace.

[MP&C]

The best repair would be a full quarter, installed as the factory did. The next would be a butt weld joined at the yellow line at top or where shown at bottom. These areas should have enough shape in them to minimize most welding deformity provide you can use some consistency in your welding method. It may be needed to hammer from the back side to get any low areas persuaded up (outwards) so if you don't have room for swinging a hammer, then the concave area would be a good choice as the hammering could be done from the outside. Get your butted joints tight as possible for an easier time with the Tig
Posted via Mobile Device

[MP&C]

be sure to check out this thread...

http://www.67-72chevytrucks.com/vboa...d.php?t=723691


for some hints on tacking with the Tig and it also shows difference in results of welding through flat area vs. bead details...

[Bigdav160]

I must be getting old (too late!) and didn't notice the top wheel arch piece is missing the bead along the edge. the front and rear pieces have this. On the driver's side I might be able to save enough of the original arch but not the passenger side.

I have an Eastwood bead roller (still in the box) but I doubt it has the correct die to fix the patch.

The alternative is put the fender flares back on to hide it (might do that anyway).

Thanks Robert, it looks like the concave section is right up on the wheel house and , I think, will be helpful if I need to use the hammer and dolly.

[pwdcougar]

Dave

Is the bead edge you are talking about?

Paul

[BR3W CITY]

Its hard to tell in those first pics, but how much of that "lip" is still good on that rear arch?

Depending on your welding and hammering ability, you could section that outer lip off the new patch as one piece. If there is enough lip left, it might be easier to radius a thin piece of the remaining patch to fill the gap. This would put your weld on the outer part of that crease, but it would be in a uniform play, which you could probably access from the inside if that inner layer isn't in the way. (I'm having a hard time articulating the idea here).

In any case, using a copper spoon or an aluminum/copper heat sink can really help you manipulate the warping. Certain amounts are inevitable.