Correct way to install tail panel

[512Fairlane]

My car had the tail panel replaced with a factory one but they did not do a very clean job where the floor meets the tail panel.  They cut the floor back too far and then used fiberglass to join the trunk floor to the tail panel.  I know this is a bad rust area on these cars and I would like to put in some patch panels to connect the old floor to the tail panel.  What is the best way to repair this area to keep it from rusting out.  Does anyone have pictures from underneath that show what this should look like or a good way to repair it to keep it from rusting in the future?

[glen b henderson]

As for as I know there are no aftermarket patch panels for this area, so you are stuck with fab'ing patches or find a doner car. Unless you are doing a full on restro, the best bet may be to fab a flat panel. This would eliminate the channel that collects dirt and water at the rear.

[RICH MUISE]

100% what Glen said...with emphasize on the "unless you're doing a full on restoration"..to factory specs. Making patch panels that look correct from the topside should be relatively easy. I'll get some pics posted later today of the original configuration.
Finding a donor car ('57 or 58) for the panel can probably be done...alot depending on which area of the country you live. I looked at over 20 junkyard cars for a donor floorpan before I found one right in my neighborhood...a '58 that I also rescued the inner rear quarters from (they were not making them at the time)...probably had the panel you need, but unfortunatly car got crushed and is probably part of a new Honda now. As you mentioned, it is a rust prone area, but not as bad as floorpans, so you might get lucky. Whoever has it will probably want an arm and a leg for it, as it will also have to have a good rear panel they will have to destroy.
when I post the pics later, I'll talk about rust prevention.
Rich

[512Fairlane]

Thanks.  I'm not too worried about factory correct I just want it cleaner that what it is and it needs to last for a long time.  Pictures would be great.

[gasman826]

I had a problem just above the tailpipe area.  I cut out the rust and made a patch.  Rather than welding it back in along the seam, I used 3M panel adhesive.  Now it is sealed and rust protected.  I'll check in fifty years and see if it worked.  I cleaned out all the old tar and media blasted the entire tailpan/trunk floor seam.  Sprayed it down with Eastwood Rust Encapsulater, epoxy primed, and finished off with 3M column foam.  The foam should strengthen and keep moisure and dirty out of the joint.  This also keeps wayward screws and change out of the joint.

[Zapato]

Gasman, 3M pillar foam how is the expansion factor on it will it push sheetmetal into a bind? or perfect for filling a void?

zap-

[512Fairlane]

After looking at it a little closer they removed most of the floor that extends down and meets at the bottom with the tail.  Looks like it was spot welded to the tail panel.  There is only a small portion left right behind the license plate.  They used fiberglass cloth inside the trunk to connect the floor to the tail.  It really doesn't look too bad from the trunk side.  I'm thinking about eliminating all of the floor portion that runs downhill and then just making a flat panel to fill in the small gap from the floor to the tail panel.  Maybe bend a lip down to adhere or weld to the tail panel.  Adhesive might be a good idea so I don't warp the tail.  Thanks for the advice.

[RICH MUISE]

Here's a few pics from the topside. I couldnot get pics from the bottom side because I rolled my pan, and the pan gets in the way of being able to photograph the area where the trunk floor meet the tailpiece..
For future protection, I did a proceedure similar to Gasman, except used different materials. After thorough cleaning and removal of old sealer, and sandblasting,I treated with Zinc Phosphate, got lots of por-15 in the seam area as well as coating the entire inside and underside ( my car is 100% prepped and por-15'd where exterior final paint wasn't going). I then sprayed adhesion promoter in the seam areas and filled with seam sealer. The finish you're looking at is duplicolor splatter paint over the por-15 and adhesion promoter followed with clearcoat matte finish. The underside got the same por-15, but with paintable undercoating and Matrix singlestage urethane.
P.S.  LOL... I have been accused of overkill more than once...but it's my peace of mind.

[512Fairlane]

Thanks for the pictures.  That looks very nice.

[gasman826]

Gasman, 3M pillar foam how is the expansion factor on it will it push sheetmetal into a bind? or perfect for filling a void?

zap-

Pillar foam is being used in new OEM applications where the gauge of steel is thinner than the '57s.  I have used the pillar foam in the header above the windshield, the A pillar, B pillar, and around the window frame of the doors as well as the tailpan area.  The foam does expand but I found that it is not strong enough to move the metal.  All places that I have used it are three sided leaving an expansion area.  I was very curious and did just a test spot on the windshield header.  Since that test, I have sprayed foam into confined areas through small holes with no issues.  I wanted to add sound insulation, temperature insulation and strength to all these areas.  I think I have succeeded. 
For filling voids, you will need to use temporary forms.  I used plastic or paper masking to 'damn' up areas where the foam would run or drip or get it the way.

[RICH MUISE]

Gary/Zap...one thing to remember about things like the foam....kinda like siding on a house...if water does get in you don't want to trap it there..it's gotta have some way of passing on thru. It's like the side windows on our '57's....those window fuzzies were just never designed to keep all the water out. That's why I converted my back windows to stationary. All of this reminds me I need to go back and put sone drainage holes in my rockers..forgot to do that before I painted.