Do you have any links for all the different terms and the basic tools one would need or want? A 'dictionary' of auto body and paint tools and terms would be useful.
DA, Air file, blocking, etc.
DA is Dual-Action sander, right?
Blocking is wrapping sandpaper in a solid object (like a 2x4
)...I think.
I'm in the tech business and we use plenty of jargon. It's easy to forget that people outside that business don't know all of the acronyms and jargon, and this thread is a good reminder of to me of how laymen feel when we talk.
Reason for asking is my recently acquired '88 GT 'Vert had the ground effects removed and the spoiler/luggage rack removed and one of the POs tried to body fill the holes. I'm in for some work in that area.
I''ll have to find and replace the ground effects and the spoiler/luggage rack, but don't know when that will happen so want to make sure I take care of those areas until then. I'll get pictures in the sunlight tomorrow. It's stored in my garage, fortunately, so no direct sun/rain.
The rear bumper has the clear coming off of it, but otherwise the paint really looks good on the car. I don't know if it was resprayed at some point or spent nearly all of it's life indoors - is there something I can look for on the car to show evidence of repainting?
It's been a busy weekend, sorry it's taken so long to reply.
First, books? I would guess so, but I couldn't tell you off the cuff.
I'll try to make the jargon understandable. If you don't know what something i'm talking about is, let me know and I'll explain it more thoroughly.
DA - Dual Action Orbital Sander. You were correct. They come in different levels of finishing based on their orbital sanding diameter pattern . I mostly use a 3/32" sander. Sometimes it's called a finishing sander.
For stripping away paint though, something with a 1/16" or greater pattern is advisable. I have a DA specifically for stripping paint. If I remember correctly it's a 5/32" pattern (I could be wrong though, I've had it for a couple decades and don't remember specifically).
An air file can be dual action or single action. Generally the ones used by bodymen are single action (they just go back and forth). First off, they have a long narrow board that the selected sandpaper is attached to. Lengths can vary from 4" to 2' that I know of. These are used during the plastic filler stage to expedite the initial straightening of the filler. They really are a form of blocking (I'll cover that in a minute). They are an AIR file, because they are driven by an attached air hose.
Blocking - Oh boy what a big subject! Like I mentioned above an air file is a form of blocking. Blocking means using a predetermined form to correct variations in a surface, wether it be flat and straight, or curved, angled, whatever the original design calls for.
So a block can be straight and flat, or it can be round, or it could be even flexible. It depends and what you're trying to do.
Most blocking on a fox will be straight. They're filled with straight lines. Though when you look at the leading edge of the hood and the back edge of the deck lid (trunk), you can see the curvature there. Generally a straight block can make even these areas look good. But how about those bumpers? A flexible block has served me well in those areas. When I say "flexible block", it almost seems oxymoronic. A block is for straightening. How do you straighten the curves of a bumper?
A flexible block. If I were at work I would show you the ones I use. They're essentially rubber blocks in the end. Relatively thin (about 1/4") in thickness. They can conform to a convex curve, yet still provide the level surface so it can take away highs and lows in a repair.
On a complex convex curve (rounded in short), about the only thing I've ever found that was effective is the palm of my hand, seriously. I'll use whatever grit the situation calls for and stick it to my hand. Sounds kind of hillbilly, but it works.
The rule of thumb for length of a block is a bit esoteric, it depends what you feel comfortable with. A 2' block could, in theory, help you to give you a super duper straight door. Yet it is very unwieldy. For most blocking on customer cars I'll use a 12" block. Though I will periodically use an 18" block for extra long flat surfaces such as a bedside of a pickup truck, or for doors that are generally the straightest panel on a vehicle.
Enough of that for now.
You say the clearcoat is coming off your bumper. This is technically delamination. Due to damage over an extended period of time from UV radiation clearcoats will peel, or delaminate. It's simply caused by the underlying base coat being broken down by exposure to UV light from the sun. Essentially the sun changes the base coat into something different from what was initially applied by the factory. When this happens, the chemical bonding that was there in the beginning between the basecoat and clearcoat is severed and the clearcoat begins to flake away. If this happens, you're stuck, the panel must be stripped of all paint. I'll explain that in more detail if you want.
Evidence of being repainted? Geez, lots of things.
Look for obvious variations in the orange peel from panel to panel. (orange peel is simply the texture of the smoothness of the paint) If it suddenly changes between panels, there's a good chance of a repaint.
If it was repainted there will be a reason for it, like damage from a wreck or maybe even rust repair. You mentioned a PO had tried to eliminate the GT ground effects. That will take painting.
Look for straight line scratches that's look to be under the paint. That probably means there is filler underneath.
Post pictures when you can and I'll tell you what I see from the picture.
