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Article: Doing a "#4" Restoration,
Last updated: 10/30/01
How Beetle Bodies are Put Together
A big part of understanding the scope of a full restoration is having a good understanding of what panels are rusted/damaged and will need to be replaced. To do this you need to understand what the panels are that make up the Beetle body. There are eight major "bolt-on" panel/assemblies on the Beetle body. Four fenders, two doors, a hood and a decklid. Obviously, if these panel/assemblies are damaged, the easiest way to replace them is just get new ones and bolt them on. But after these eight things are removed, the bare shell that is left is entirely welded together.
Now grab any decent VW parts catalog and
you will invariably find a "body" section with an exploded view of the
body, at least to the extent that panels are available. This is a good
way to start getting an understanding of the panels that make up the car.
And it is a good way to get an understanding of the common replaceable
Spotwelds: What are they?
In an ideal resto, you will be replacing whole panels, just like was used at the factory, with new ones, that were made at the same time your car was made and preserved in a climate controlled store room until you came looking for them. And the rust/damage on the panel you are replacing will have known to stop right at the panel edge, leaving you a perfect, original panel to attach the new one to. Well folks, guess what? Big surprise, there is no "ideal" restoration. Yes, you may get lucky and find an NOS (Means "New Old Stock", it is a replacement part that is as old as the car it is meant for, but never has been on a car. Old stock that is new, see?) rear apron for your '71. But try to find all the panels that make up everything forward of the gas tank for a '57 (I did), and you will be using a real hodge-podge of parts. In my own '57, the nose is made up of parts that came from five different sources.
But before we go into the surgical "unwelding techniques", let me address cutting panels in general. Keep in mind that "unwelding" means that you have to break welds. Sometimes that is not the best "take apart" method. In some cases, just cutting the steel at a junction, or even mid-panel is fine. Possibly because you will butt or corner weld the panels together, or perhaps you are just patching a cut out area (especially true if you are doing a "4B"resto ). Here are some of the methods I use to cut panels, ordered with the most often used ones first:
Anyway, the point is that if you are doing
a sorta-ideal resto, you will need to remove the whole original
panel (or what is left of it), and replace it with a whole 'nother one.
So how do you remove a whole panel? Lets start with some basic "unwelding"
Spotwelds: Taking them apart
|This is classic "donor" panel that I was using when doing the final metal work on my '57. I needed some steel to patch a rust perforated area in the rear quarter. This panel (its upside down) is from the car's original front left quarter. You can see part of the inner wheel arch (top) and that box section is what the gas tank rested on. I decided to remove this box section, flatten it out and use the metal for the patch as it was slightly thicker than the usual body metal and the patch was needed in an area behind the rear bumper support. In this case, "beefier" would be better.|
|Being able to find
spotwelds can sometimes be really tricky. As it turns out on this panel
they were very easily seen (at the arrows in the picture). On some panels
though, they are all but invisible. Usually, they create a slight depression
in the metal. But this can easily be obscured by dirt, paint, rust, etc.
It takes a trained eye. Here are some of my tricks (you may use any one
or combination of these) for finding them:
Whatever you do, do not grind the panel, this will virtually erase the spot welds!
|This how I remove the
welds. You want to drill through just one panel's thickness with a sharp
3/16" drill bit. You want to think about which side you do this from (if
you have a choice), you want to drill the panel that you don't want
to save. Being able to drill through just one panel is tricky. Go buy yourself
a nice new 3/16 drill bit. I like the cobalt or titanium kind. You want
a bit that will make as much of a "flat hole" as possible. Look at the
drill bit point, is it very pointy? (like a pencil end) You don't want
that. You want one with just a sharp point in the very center point but
a flat "blade" area on the nose (a "brad point" bit, if you can find one
this size, is almost perfect but, since most all of them are made only
for wood, it may not last long). Make sense? This will allow you to drill
away the spot weld without removing too much material from the panel behind.
In the picture above, you can see that the holes are still slightly conical
though. Those "Bullet" tipped ones are OK but not preferred. That little
bullet "nose" will have made a small hole in panel behind by time the rest
of the bit has cut away the near panel.
Use an AC line powered drill, you need the speed. My cordless drills don't turn fast enough. You have to watch the bit progress into the metal and know when to stop. It is an art. Better to go to shallow and come back and drill a bit further again later if needed.
Sometimes you may want to drill all the way through the panel you will be re-using because you will be "simulating spotwelds" (see below) when you re-assemble. In this case, any bit will do, just drill all the way through.
|Now, about that chisel.
I use a woodworkers chisel. I like it because it has a flat and a beveled
side and is easily sharpened on my bench grinder. A good sharp chisel is
a must. In this picture, I have driven the chisel between the panels and
separated the spotweld. I have oriented the chisel with the flat side against
the panel that I am trying to preserve (the near panel, the one with
the holes in this case), this reduces distortion of the metal around the
weld, but that is not all that important.
If you have precisely drilled out the spot weld, the panel will come apart easily (with a nice "tanNGG!" sound). I have separated many that were drilled correctly with just my hands. But if you drilling is slightly off center and/or not quite deep enough, a good sharp chisel will finish the job for you. But watch the area as drive the chisel in, it can easily start to "tear" the metal around the weld depending on how it approaches the welded area. Patience will pay off especially if you are extracting that "nowhere to be found in the world" panel. If you bend up the edge a bit taking the panel off, don't worry. It is easily straightened out again with a hammer and dolly.
|This is the backside of the panel. Not the best pic, but as it is the fender well side, it is much more cruddy and much harder to see the spotwelds. You can see where I wire brushed a bit along the area where the spotwelds were. In spite of the fact that you can't see them in this picture, I could see them well enough to drill them out. All of the welds on the nearside of the box channel have already been broken as you can see.|
|Here is the panel separated. Yes, I drilled all the way through on one, and almost through on another. No big deal here as the panel underneath was not needed.|
There is a tool you can buy called a "spotweld cutter". It looks like a very small hole saw and only cuts down to about a 20 gauge depth. Effective, but it cuts waaayy too much metal out for me. The smallest one I could find cut about a 3/8" hole. It leaves the cut out circle of metal attached to the backside panel, you just grind it off. Neat tool to have, but I just don't use mine much.
That is the basics of breaking spotwelds. Half of the technique is just being able to find them, the other half is being able to drill away just enough. Then of course there is patience and a nice, new, sharp drill bit. Take your time, drill a bit, pry a bit with the chisel, wiggle a lot. You will surprised at how cleanly you will be able to remove a panel that was weld by a factory worker in Wolfsburg decades ago.
Copyright© 1998; John S. Henry