bb80sc/TRE/AutoInno project update

[KevinP73]

Brad wasn't very happy with duck tail on his car. It wasn't one of the better tails available even though the best available is still a far cry from being show worthy. It was decided to bond his existing tail onto a steel deck lid to improve the fit.
A look at the tail shows a huge gap at the leading edge as well as a misalignment with the body.

You can see here also that the gaps on the sides of the tail are extreme.

The first step in the procedure is to separate the top and bottom halves of the 'glass tail.
Here is the upper portion of the tail removed from the lower with the mating surfaces ground clean
in preparation for bonding to the metal base.

An OEM deck lid is trimmed leaving at least a two inch "bonding surface" all the way around the deck lid.

You can also see in this picture that I have left the recess surrounding the grille intact as well as the latch support. The grille area on most ducks have shrunk to the point that in order to install a grille you have to trim it.
And the tabs for the mounts are usually too frail to work properly. I'll make this tail so the grille recess is all metal.
I'll explain later how I plan to modify the latch support so it still works.
A test fit of the two parts shows the tail will have a metal edge the full circumference the exact size and contour of the OEM part.

[KevinP73]

With the two parts ground and test fit I can mix my bonding agent. I don't have any pictures of applying the bonding agent to the parts only because I have to work guickly and can't take time to shoot pics. The material has about a 15 work window and it takes all that time to "butter" both parts and to get the clamps on the part.
Here are a couple shots of the parts bonded with clamps in place.


You see that the metal grill recess doesn't mate with the corresponding area of the 'glass tail just yet. I'll make adjustments to these areas as I proceed.
I'll let the bonding agent cure for about 24hrs before continuing.
Stay tuned.

[89turbocabmike]

Nice Kevin, I learn so much from seeing your process. Thanks for sharing

[MotoSook]

Nice work Kevin. I am doing the same thing to my ducktail reject. Now I have someone to call

[efhughes3]

Nice work, and a unique way to approach this periodic dilemna.

Having said that, my duck doesn't have near those kind of gaps, and my stock grill fit in perfectly. It goes to show the variances seen in aftermarket parts.

[Zeke]

The ducks I have run across in this deal and that all had the wide side gaps. In the past, on parts such as a duck, I have added a Fglass edge by using some waxed alum under where I want to add. Then, I flip it over, peel the metal and add more glass. At that point, after curing, the new edge can be trimmed to fit.

Kevin, your way is another approach and I think it will make a strong, straight lid. But, are you getting some build up? I guess you will lower the lid at the hinges and at the bump stops to flush it up to compensate.

Great work!! You are the master, I was just adding thoughts about another method if someone doesn't have an existing lid to bond the skin to.

[deoxford]

What is your bonding agent?

[KevinP73]

Originally posted by Zeke
But, are you getting some build up? I

I can taper the forward edge of the tail down to zero so there is no need to make any adjustments on the hings. Same for the trailing edge. taper to zero. The sides only increase by about an 1/8' so it's easy to adjust the bumper stops.

[KevinP73]

Originally posted by deoxford
What is your bonding agent?

It's a Bondo brand product called "Fiberglass Resin Jelly" with short hair filler added.

[Vipergrün]

VERY Cool!! Thank for the update Kevin!

[Nathans_Dad]

Is there any danger of separation between the metal and fiberglass given the engine lid temps?

[Zeke]

Originally posted by Nathans_Dad
Is there any danger of separation between the metal and fiberglass given the engine lid temps?

That's a good question. Actually, sitting in the hot sun can produce hotter temps than the engine will running and driving. There may be a different rate of expansion between the two materials, but as you see, Kevin is only bonding around the perimeter. This provides plenty of opportunity for the different components to move, plus the bonding agent is flexible to an exent. All polyester products have some flex built in nowadays. If not, the parts would be like bakelite, extemely brittle.

I'm not hijacking your thread, am I Kevin? I got my first job in fiberglass in 1965 and have been around the stuff for a while now. I don't mean to steal your thunder. You do marvelous work.

[KevinP73]

Originally posted by Nathans_Dad
Is there any danger of separation between the metal and fiberglass given the engine lid temps?

Sure! but I figure I'll have the check cashed long before that happens!
errr I mean. One reason for using the bonding agent I use is because it has a greater working thickness than most agents. This should allow for greater flexibility between the two parts during the heat cycling that occurs. That and on a project like this I'll include a lifetme gaurentee so Brad doesn't have to worry unless he backs over it in the driveway or something.

[Nathans_Dad]

Cool! For those of us with stock decklids, is it cheaper or better to go the bonding way with your stock steel lid rather than a fiberglass one? Does anyone even make just the duck to bond to your stock lid like you did?

[jm529]

nice job and a great idea, kevin... how much of an overlap do you have for the glass to bond on the metal? you ever have a problem with the seams showing or bleeding thru in the future? i think i would use a more flexible panel adhesive and glass w/cloth over the seams just in case.

jim

[Jeff Alton]

Very impressive work. But, I have to ask, I don't what your labor rate is but would it not have been easier and perhaps cheaper to start with a fair or good fitting tail and get the fit you are after that way? I am sure you have fitted lots of tails (ummmm does that sound right?! ) so you have a better idea how much work that is, but this seems like a lot of work too...

Once again, very impressive, as was the roof work.

Cheers

[Jack Olsen]

A well-fitted fiberglass tail doesn't have half the cool factor of a steel/fiberglass hybrid.

My guess is that Brad will have much greater durability, over the decades, at the points where the hinges, latch and grill attach to the decklid.

[KevinP73]

Rick, this method is best suited for the guy who finds that $50.00 duck tail at the swap meet or e-bay. It's very time/labor intensive but if your short on hobby dollars and long on spare time then it's a winner. Plus the end result mimicks the factory's product.

Jim, Yes there is always the chance that the bonding surfaces will seperate. Thats where years of experience come into value. I lay out the project where the seams and joints are least visible. I'll cover all the joints as well as I can from the backside with a layer of 'glass.

Jeff, Yes it's a lot of work and in most cases it would be faster and cheaper to just toss the bad part and get a good one. On some projects I get the luxury of unplugging the time clock and being able to show what I'm really capable of doing.

[Drago]

Shameless self-promotion...I like it. Nice work!

[opticalfuel]

I am working on my own little duck tail disaster, but starting from less fiberglass experience than most. I am in no hurry which allows me to learn the most I can by reading and re-reading this and other posts that cover the subject. I am good at following a good example. It's the way my Dad taught me to do things. Watch and notice the details, and don't be in too much of a hurry. Part of the fun is getting there. My project is just that. Getting there.

Right now I have the two major components that I need to create a good Duck tail: the beat up/ half dead ducktail (badly fitting) and a very clean stock lid, ready for transplant:

Duck Tail Cut-N-Paste?

I am currently reviewing the above directions, and modifying my plan. I'll try to post pictures as I go. Maybe I can have my son snap pictures as I wield the FG Bonding agent and clamp the monster together. It should be fun.

Hate to cut into the existing stock lid, but I guess that is the way it should be done.

First things first. I have to separate the two halves of the ducktail (a job in itself) and repair the broken portion. It has a nice failure in the high stress area (typical of where it always breaks) near the left top lid support)

I'll keep you posted. (I'll update the post mentioned above - and keep my stuff there)