Well, I guess the second time was a charm. I am having trouble getting
messages to this list, so in case you didnt get the last one, I will recap
the whole procedure for replacing inside lower door panels on the AD's:
The replacement panel (from Chevy Duty) is very nicely made and of
appropriate thickness so its definitely not the panel if you have problems!
I have been taking the advice of many different people both locally and
here. I must add however, there is no substitute for common sense and
creativity. For example, on the first try, I was told to flange the top
(long end) of the patch panel to give the welded area more strength. This is
normally good advice, however in this case where there is NO support across
the door, more is needed. I reasoned that a 16 gauge strip about an inch and
a half wide then bent about a half inch inward to a 90 degree angle (angle
iron basically only thinner) would serve as a much stronger flange and if
positioned right, would be right under the weld line. This gives strength in
both directions and a thicker flange will also dissipate the heat better.
So, nevermind a flanging tool and all that. Just weld this flange right to
the patch panel and off you go.
Once you have the hole cut out and the patch panel with flange in the hole,
its important to clamp it in several places to hold it exactly where you
want it to end up. This is also common sense, but there are many factors
that make it difficult. In this case, there is a crimped bottom that you
must contend with. Since the reason for this excercise in the first place
was rust thru, and the crimped bottom was also toast, I bent the crimp up 90
degrees, then took the die grinder and cut it clear off leaving about 1/32
or so sticking outward to receive the new strip that must now be welded in.
Once this crimp is removed, clamping the patch in place is easier and more
Now for the welding.. I used compressed air to immediately cool the welds. I
spot welded it in going from one side of the panel to the other until the
welds met in the middle. Doing this evenly will draw the metal inward evenly
causing less warp. I welded about a 3/4 inch weld each time. Any more will
end up in disaster. I also used a pretty hot setting of "F" and "6" on my
Lincoln SP175. Using the correct 88/12 Argon/CO2 gas also helps. These
factors provided a very melted and very smooth weld as long as you get in
and get out fast. With that high heat you run the risk of burn thru. But if
you go with lower heat, you will warp it because you have to hold it there
longer to penetrate. Welder in one hand, air blower in the other.. weld then
blow it off until its completely cool.
The crimp area needed about a 7/16 strip welded to the bottom of the door.
This is a bit more delicate and a lot more fun since it goes really well.
Set the welder to about "C" and "4" for lower voltage and less wire, clamp
the piece and here you can do around a 1" weld at a time. It goes very fast
and if you are careful, no burn thru and a very nice uniform strip will be
I had perfect success on this last try. I was so relieved. As someone who
hasnt had a welder in his hand but for about a month, and this being my
first try on real parts of the project, I guess 2 trys to figure it out is
okay. I cant take hardly ANY credit however.. its YOU guys that really made
the difference. You not only gave me specific advice, but got me to thinking
about how to make something even better than those Chevy guys in 1950. My
truck will have both doors with angled supports across the inside lower door
panel for lightweight but added strength. Now on to the drivers side door.
But first I am fitting this door on the cab and making sure all is well. I
am sure its fine since its the original door and there was no warpage but it
doesnt hurt to be sure at every step.
1950 3100 * 1949 3600
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