Body - Gluing the roof back on

Well after many hours just sitting in the shed looking at the coupe from every conceivable angle, I am finally ready to join the chopped roof back onto the body. I am glad I did ponder like this for a while as I did end up taking another inch out of the back of the roof to get it to look right and I also have it pretty clear in my mind now how the windscreen frame and cowl will come together. Its important to just sit and assess or you can spend a lot of time redoing things or worse still find out too late that you should have changed something.

Anyway today was the day to start putting it back together.....so how do you join fibreglass that has been cut? Actually its pretty forgiving stuff. New fibreglass bonds to the old almost seamlessly, so any mistakes can easily be repaired.....but there is a right and a wrong way. I am no expert but I will try and explain.

When you cut and join two pieces and look at them in cross section they look a bit like this. The two pieces butt up to one another. Now if you glued the join....the bold black line.....it wouldn't last too long. It would definitely glue together okay with fibreglass resin, but with a car body in particular, they flex and twist and in no time at all your expensive paint job would be ruined with big cracks appearing.

 

You could put fibreglass resin and cloth on either side of the join. This would indeed be strong, but you can't have a big lump like that over all the joins.

So what would happen is you would sand the big lump down on the outside of the car to look like this. As you can see the outer patch has gone and while this joint is stronger than the first example it would still crack at the join in time.

So what you have to do is this. Firstly grind down into the join from one side like this.

Once that has been done fill the hollow with resin and fibreglass matting like this. 

 

Once that has hardened. You then hollow out from the other side.

And then you fill that hollow with resin and fibreglass matting as well. You then end up with a cross section that looks like this. Now that doesn't have a small join that will crack. Instead there is a much larger surface area for the new materials and the old fibreglass to hang on to one another.

 

 There you have it. That's what I need to do to all the cuts I made to the roof, the window frame and around the rear window. Here is the body outside all ready to go. As you can imagine all this grinding away of fibreglass is going to make a lot of dust.

Now for any of you who have worked with fibreglass like insulation for example, you'll know how prickly and itchy it can make your skin.......so I need to kit up for this lot. Here is a pic of me about to get underway.

And here I am in action with the grinder.

Once I had ground away the inside of the joins they looked like this.

After that it was a case of mixing up the resin and the hardener as I showed you in my earlier blog "Fibreglassing the Windscreen Frame" and layering that with fibreglass cloth. Initially I just added a couple of layers of fibreglass between the bolts that were still in place to hold all the pieces together. You can see below the fibreglass has been added (yes it is there despite the light shining through the join. The resin and matting almost go transparent. You can also see one of the bolts holding the two parts together.

 

Later on (next day actually) the two layers of fibreglass had gone hard enough and the joins were strong enough for me to take the bolts out. Once that was done I ground out the rest of the joins I couldn't get to before when the bolts were in place....and once again fibreglassed. Now that the entire join was clear I added several more layers to build up the join.

Below is what the joins look like now and without light shining in from the other side.

And here is what they look like from the outside.

I am actually pretty happy with the outcome and I am confident it will be strong enough and will look okay too once I ground out the outer joins and glassed them up again. Bring on another fine weekend next weekend.......oh but read on first there is some other bits I attended to while I had the tools and the materials at hand.

I decided I would have a crack at re-doing the the "A" pillars. They are the first pillars. The ones by the windscreen. Hence the name "A" as opposed to "B" pillars which are the second pillar behind the front doors on a car. And if its a 4 door car, the "C" pillar is behind the back doors.

So what did I have to do to the "A" pillars? Well they don't quite line up with the line of the roof. You can see here how the two angles just don't meet.

Here is a close up look. Ugly!

My mate Bill came round to give me a hand to lift the body outside and we got chatting about the issue I was looking at. He suggested I look at splitting the pillar down the middle and open up to see if the angles better matched then. I pondered on this and I could see that it might help, so that is what I did. You can see in this next pic I have a tape line running the length of the pillar where I was going to cut.

As I have shown you I need the top of the pillar to line up with roof, but I also need to look at the bottom of the pillar at the same time, to make sure that would line up too. 

The doors on the coupe will be pillarless, (there will be no frame around the glass) and the top of the door will line up with the bodyline directly above the swage line. The swage being the ribbed lined that runs along the side of the car.

You can see in this close up the bodyline that will line up with the top of the doors is 2 1/4 inches above the swage line. That is where I need the "A" pillar to end up to, so I transferred that measurement to the front of the door frame.

Here you can see I have cut the stump of the door frame down to 2 1/4 inches above the swage line to match.

I can now measure between the roof and the stump of the door frame to work out how long the pillar will need to be.

Here is the pillar and I am transferring the measurement onto it.
I have added a tape where I can now cut the pillar.

Here you can see the bottom of the pillar sitting on the stump of the door frame.

And here is what it looks like at the top. You can also see in this pic just how much the pillar needed to be opened up once it was split down the middle.

To overcome the difference between the roof line and the pillar I came up with an idea. I would take a "V" out of the pillar like this....

Then by making multiple cuts on the side.

And alternating cuts on the underside.

 

The pillar became flexible as you can see in the next two pics.

 

There you go, just like that.

 

I then did the same with the roof.

 

Now the two should line up. As you can see, they did. I taped all this in place from the outside so I could glass it in from the back. The idea being that the tape would act as a mould and that it would easily pull away once the fibreglass had hardened.

I had to use a clamp (thanks Roger) to help hold things in place.....then fibreglass, fibreglass and more fibreglass.

Here you can see what it looks like inside with the fibreglass now applied. Not the prettiest but it will work I think.

Here's a view from the front of the car.

 

And as if thats not enough.....that's it for this weekend. Next weekend if its fine I will attack the outside of those pillars and all those roof chop joins. Stay tuned!