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After installing the replacement rear deck in the last update the next step in
our Corvette restoration project was to align and install the replacement tail
light panel. As you'll recall, the original was totally shot and damaged
beyond repair. After giving it a bit of consideration I chose to purchase a hand
layered panel instead of a factory correct press-molded panel in an effort to
save some money. In my case I'm not overly concerned with originality so the
cost savings made the trade off worthwhile to me.
As anyone who's worked with replacement fiberglass panels already knows, some
amount of trimming and fitting of the replacement panel is required to achieve
the proper fit. As a starting point I used the contours of the bonding strips on
each side of the car to set the initial height and alignment of the tail light
panel.
Once in place the panel was clamped in place to allow a more detailed fit-up to
be completed.
Much like the rear deck, the tail light panel needs to be adjusted in three
dimensions: 1.) up and down, 2.) left and right, and 3.) front to back alignment
at the bottom of the panel. In my case criteria two and three were essentially
set by the bonding strips and body panels that were already in place. That left
setting the vertical alignment of the panel.
To set the vertical alignment of the panel I marked out the centerline of the
rear deck, and then drew vertical offset lines at 15" and 22" left and right.
A tape measure was
then used to take vertical measurements from the top of the rear deck to the lip near the bottom of the tail light panel
at each offset mark. The theory behind this is that, if the tail light panel is
properly aligned to the rear deck, the measurement at 22" left will match the
measurement taken at 22" right and the measurements at 15" left and right should
also match. The final alignment of the panel
was then set by balancing these measurements while also maintaining the body
line set by the drivers side quarter panel.
For what it's worth, if you're replacing only the tail light panel and both rear quarter panels are in
place this becomes a fairly simple task. In this case the panel alignment could
be easily set by matching the body lines on the tail
light
panel with the lines set by both rear quarter panels.
With the alignment of the tail light panel set several alignment marks were made
with a black marker to allow the panel to be easily repositioned after trimming.
Next, the job of marking the panel for trimming was
started. First, the sides of the panel were marked using a pencil..
Next, the top of the tail light panel was traced along its full length. Once
traced
the tail light panel was removed and measurements were taken between the trace line and the
edge of the rear deck at approximately 12 inches on center. These measurements
represent the minimum amount of material that needs to be removed from the edge
of the tail light panel.
Initially, the panel was marked to remove only as much material as required.
More material was removed later in the process to
provide reasonable clearance between the edges of the rear deck and tail light
panel. This 'play-it-safe' approach helps prevent over trimming the panel.
Once the distances were transcribed to the tail light panel the points were connected using a straight edge ruler
and a black permanent marker.
Next the panel the edges were trimmed. Using a die grinder with a 24 grit sanding disc
made pretty quick work of this task.
After completing the first round of trimming the panel was aligned back on the car and additional
measurements were made and transcribed to the panel. These marks were laid out
to provide a gap of about 1/8" between the edges of the adjacent panels.
After all trimming was completed
the rough edges and lines of the panel were evened out using a DA sander with a 200 grit sanding disc.
The next step of the installation process was adjusting the thickness of the replacement panel. I found the
new tail light panel was about 1/16" to 1/8" thicker than the original press
molded components. I suspect this is typical for most hand layered replacement
panels. In order to
provide a flush surface between new and proposed parts, the thickness of the
tail light panel was sanded
down as needed along the bonding surfaces. Whereas the bonding strips project
approximately 3/4" beyond the edge of the panel this sanding process was
concentrated to an area within 1" of the panel edge. Once again a die grinder
with a 24 grit sanding disc was used - just be sure not to remove too much
material!
In order to achieve an even surface a simple dial caliper was used to take measurements as material was
removed from the back of the panel. The goal here is to grind down the back of the panel so that
the back surface is parallel with the front surface. This ensures the panel will
lay flat on the bonding strip and will produce the best possible fit and finish.
Using the caliper allowed me to
easily determine if more material needed to be removed from the edge of the
panel, or nearer the center.
In the photo below you can see the caliper is tight to the panel near the black line (the traced edge of the
bonding strip), but a gap exists near the edge of the panel. In this case, more material needed to be
removed near the black line to provide an even surface. Removing the extra material was completed as a series of steps.
First, a bit of material
would be removed from each area of the panel. Next,
the panel would be test fit to the car and a note would be made regarding how much more material needed to be
removed. Lastly, the panel would be removed and sanded down. This process was
repeated, removing a bit of material after each test fit, until the desired
result was achieved. It took about two dozen trips back and forth, but
eventually I ended up with a panel that had excellent fit and finish.
After all of the trimming was completed, the panel was once again clamped to
the rear clip and adjusted to the desired final position.
Once in place the edges of the tail light panel and underlying bonding strips were drilled to accept
temporary screws. Here we used the same process that was used during the
Rear Deck Installation.
Additional details on this method of temporarily holding the panel in place can
be viewed starting approximately half way through that update.
In this case holes were drilled at approximately six inches on
center. In two locations I was able to eliminate screws by using my long reach
vice grip clamps. It's not a huge savings, but it's something!
After completing the drilling process the panel was removed one last time and
the mating surfaces were smoothed out using a DA sander with a 200 grit sanding
disc. This process was also used to blend the sanded down portion of the panel
into the surrounding area.
After cleaning the tail light panel and bonding strips with lacquer thinner
epoxy adhesive was applied to the back side of the new panel. Once again,
Lord Fusor 127EZ epoxy adhesive was used to bond the panel to the
rear clip (click the link and scroll 3/4 of the way down the page for more
information).
Once the adhesive was applied the screws and washers were given a quick spray
with WD-40 (to prevent the adhesive from gluing them in place), the panel was
positioned, and the screws were installed and tightened. As noted in the last update, it
doesn't take a lot of pressure to pull the panels together so be sure to work
carefully to avoid stripping the screws or squeezing out too much adhesive from
between the panel and bonding strip.
Once the screws were in place the adhesive was left to harden.
The next steps will be to install the new rear quarter panel, followed by the
new rear valence panel. Before long this Corvette may actually start looking
like a car again!
As always, thanks for stopping by to check out my progress.
Another update should be posted in about a month. IN the meantime, why not stop
by the new Corvette
Restoration Forum to discuss the project, ask your questions, or just to see
what other folks are saying.
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