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Butt Welds and trim gaps

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  • Butt Welds and trim gaps

    I've always said we should be using butt welds, and trimming panels as tightly as we can get them. Some recent shop work helps to show that process, so hopefully this will help out someone with patch panels.

    The owner of the Biederman truck we had done all those rust repairs and fabrications on also has a 51 Ford F7 with a Rollback body. He was driving it down the road a few months back when the Delco Remy voltage regulator on the firewall malfunctioned and resulted in an electrical fire. The heat caused some of the filler on the outside of the hood above the fire to delaminate, showing up as circles in the paint. As we sanded these defects out it was noticed that an abundance of filler (+1/4") had been used. The more we looked, the more filler we found all over the hood. In an effort to yield some weight savings, the entire outside of the hood was stripped..

    In order to have free access for planishing out the Atlantic Ocean defects, the hood brace was removed from the inside...

    This revealed more defects that the last shop saw as fixes, but they won't leave my shop like that....
    Rather than butt weld in the proper thickness metal, a piece of about 16 gauge is slipped behind the rust hole area (from dirt accumulating between brace and hood skin) and MIG welded around the perimeter. I think we can improve on that..

    In addition to that, the brace had lost it's structural integrity, so we will remake the ends..

    To start our repairs, a body sweep is used to capture the lower flange profile. Note that a profile cut out of construction paper/cardboard works as well.

    Verifying the panel thickness. Despite this being an early 50's truck, despite this being a BIG truck, yes, the outer sheet metal here is STILL only 19 gauge.

    The affected area was cut out using an air body saw, use what you have available. Note we have no corners in the cut to help improve consistency in weld shrinkage on either side.

    The flange bend line is traced from our profile template/body sweep, and bent using tipping wheel on the bead roller (since it's not a straight bend). Here test fitted to the hood..

    An Ice Pick (something everyone should have if doing this type of work) is used to mark the area of the cut and more importantly, the cuts for the flanges.

    Next we trim the panel on the band saw leaving 1/4" extra around our marks. Next, we use offset snips and trim the flanges to the lines scribed. And ONLY the flanges.. Then the panel is re-fitted with the flanges flush with the original, and RE-scribe the round line, this time with more force to see the mark better.

    Note the scribe line has moved closer toward the flange as we located the panel correctly with flanges flush..

    Fitted... panel should be as tight as you can get it to minimize any shrinking/pulling.

    Flanges and outer surface are both aligned to the original first and I use TIG to tack on the exact corner on both ends to maintain this alignment.. Side note.... tacking only one end and working around to the other may shrink as you go, pulling other end down where it no longer aligns. So in this case, align both ends, tack both ends, and then progressively work your tacks side to side toward the bottom of the circle.

    Note here the flange was left long on our replacement. Trying to weld it in place already trimmed to fit will invariably cause the edge to burn back, making it more difficult to weld this seam all the way to the edge. Leaving the flange on our patch long makes the outer part serve as a heat sink where this burn back effect is less of an issue. Once the welds are dressed, trim the excess using offset snips..

  • #2
    Thanks, Robert. When I get done practicing on less critical projects, I've got to redo the rear window channel on my Galaxie. This tutorial helps.


    • #3
      Great neat work..... when it gets like the photo Iā€™m about to show you ... just give up and go and work in a charity shop .

      Click image for larger version  Name:	D386F8A7-D5FB-4B72-B3E9-BC47E92EA0D0.jpeg Views:	0 Size:	1.82 MB ID:	2746
      Last edited by Moving molecules .; 19-03-20, 09:58 PM.


      • #4
        BF 608 Snap on .. my favourite hammer had my one since 94 .... you know you can date them !!! ... there are Charts on the internet...... Sorry am so Sad.šŸ¤£šŸ¤£šŸ˜‰


        • #5
          Good tips Robert; thanks for posting,

          Cheers Charlie


          • #6
            Run on Tabs are a must for Aluminium and braze MIG ,TIG or Gas welding... bringing the heat up to temperature before you start the main panel .
            also good for steelwork like you say above to create perfect Crater free edges.

            for aluminium use slightly bigger tabs .... clean . Clean , and learn about your AC balance with TIG .

            has anybody tried I helium mix ?.


            • #7
              great work as usual robert! thanks for posting

              i always seem to struggle when following lines that are very close, so now i lightly scribe to cut off the excess. wipe the patch or panel with engineers blue dye, then scribe and cut. then wash the crap off before welding lol. i just find it a bit easier nowadays
              thanks neil


              • #8
                Nice Work Robert! Looking forward to part 2.


                • #9
                  Thanks for the comments and following along!

                  The TIG is used to fully weld the patches in place...

                  Front side:

                  Back side, full penetration on the weld..

                  The weld seams are then planished and dressed. Next, the front of the hood had a stress crack adjacent to one of the rubber bumpers. To stabilize the hood prior to cutting out this area, the brace is clamped back in place..

                  The damaged area is cut out, a "doubler" had been used toward the front to add strength to the area, so care is used to not cut that off..

                  A replacement patch is cut out, bends added, and tacked in place. A plug weld ties this in with the doubler..

                  All trimmed and welds dressed, the hood bumper hole is re-drilled in the new patch. Then we notice a bit of filler closer to the nose of the hood (arrow). Let's remove that while we're here to see what carnage lies in wait.

                  Gotta love this game of dominos..

                  The low area needs to be bumped up, and with little room for swinging hammers, a new tool is in order. Using the South Bend "milling machine" a die is made for the outer portion..

                  Using a pair of C-clamp vise grips (there goes another pair) the die we made will be welded to one side, the opposite is giving a bit of a trim to better fit in the confines of the slight gap available on the inside..

                  I missed the action shots, but the clamping of the vise grip is used to raise the low areas. Then dressed out for a much better "filler free" lower edge for the hood.

                  With Mike having completed the dies to duplicate the ribs in the hood brace we did a test run on a piece of 16 Ga cold rolled steel. First upper die addresses middle rib only, way to much drawing going on to expect this out of one set of dies...

                  Then top die is changed out for the remainder of the ribs...

                  A bit of fine tuning needed, but looks like this process will work to repair the rot in the bottom of the brace ends..


                  • #10
                    Sweet work Brother!


                    • #11

                      Now to fine tune our dies for the hood brace. Looking at our original profile template, the first upsweep (red arrow) and second upsweep (yellow arrow) are both nearly vertical as compared to the opposite side.

                      Our first test run shows the first upsweep spread too wide, not enough vertical...

                      Looking at the die that was made, a bit too much material was removed such that this vertical feature was lost...

                      So a new die was made for the top, this time out of aluminum. The phenolic is somewhat easy to cut out but does have challenges in making crisp bend details, so lets see if the aluminum helps out..

                      Next run, this time we'll do two panels in case they work... First pass to draw the metal into the center rib...

                      This is about 8 passes, each progressively deeper. The circle fixture to the right in the picture (white base) is used as a back stop to keep our rib centered.

                      This is about 9/16 of depth, so quite a bit of draw.. Next, the new top die is added and goes through the same 8 progressive passes.. Note in the next picture the vertical upsweeps are both nearly vertical. Success!

                      Matching up to the original, this looks like the right replacement.

                      video version:



                      • #12
                        thank you for posting robert, i always make my dies from steel, for some reason i always think aluminium would be too soft lol, i think i will try ali for the next set of dies i have to make. i guess there would be less marking too?

                        nice work as always
                        thanks neil


                        • #13
                          Top work Robert!


                          • #14
                            Robert I must applaud you ... l love... The old school determination can-do ...sorry Will do attitude to metal shaping.....
                            What Pullmax do you use.... Have you tried nylon dies ....
                            cheers Matt... Precision Panel Craft .


                            • #15
                              Thanks for the comments! Neil, I used the aluminum more than anything just because it was sitting there in the scrap pile and was the right width for the tool holder. I must say it did well. Matt, I have a Lennox TE250. They don't have quite the adjustment of some of the Pullmax machines. Or the oil leak... šŸ˜

                              Progress on the hood, the bead details in the brace are offset on the ends to match the hood opening flange. So we use a Vernier protractor to find the angle, and transfer that to our panel. This is where the transition of the taper starts..

                              Once tapered, the excess is removed from the bottom side and the outer seams TIG welded in place.

                              A piece of round stock has a radius added to serve as a hammer form for the beads. They are hammered around and excess removed from the back side..

                              A piece of 16 gauge cold rolled steel is trimmed to fit and TIG welded in place.

                              Welds dressed and media blasted..

                              The bend line is transposed from the original. As this bend is slightly convex, it was started using a tipping wheel on the bead roller to a 45* angle, and then finished on the mag brake.

                              A reminder of the carnage we are repairing:


                              A profile template is made prior to cutting out the old....