Paint and Body Fox Body Painting 101

02 281 GT said:

Another quick question for @Davedacarpainter

The instructions for the gun I just bought say to fill the cup with solvent and spray it to remove any preservation oils that may still be present in the gun before trying to spray any paint or primer. What solvent would you recommend?

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Lacquer thinner

lemosley1973 said:

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?

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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.

billison said:

Are you trying to convert a GT to lx?

If so, those holes all need welded.

And you want to cover the metal with a etch or 2k primer, even if inside

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Nah Bill, he's going back to GT after the po removed the effects.

lemosley1973 said:

Nothing owed to me, let alone an apology - that you put up the thread to answer questions is more than enough for me. Thanks for doing this.

I don't see any evidence of your description of repainting but I'll look more closely. The paint color looks uniform throughout.

What you describe about blocking makes sense from my limited sanding on just wood and some complex curves - sometimes your hand is the only thing that works, but otherwise you want to use a solid, wider object.

Here is what I am into I can see some rust already where the holes were. Since I don't have any idea when can get it painted or the ground effects replaced, what can I do to prevent rust and still have the car driveable? There are other issues to sort first, starting with the 31 year old seat belts, very annoying squeaking from the recently replaced clutch, horn not working, etc.

FWIW it's worth it will be kept in the garage and see no rain, unless it happens to rain while I'm out.



The passenger side looks like this as well, with some rust near the rear wheel where the ground effects brackets mounted. I assume that this means all of these panels need to be repainted, eventually, which essentially means the entire car will need to be repainted? A shame, because if they hadn't done this, the rest of the paint seems to be in good shape and probably could have been touched up, buffed, and cleared again.


Rear deck.

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Your car was completely refinished whenever the holes were filled and the cowl hood was added. So it would probably look better if you refinish it completely this time around.

It would be interesting to check if there was more work done to it than filling in the GT holes. Why go through all that troubleof refinishing completely and not fix other issues?

You can get a cheap mil gauge from Harbor Freight to check for previous repair work. It's simply a magnetic gauge that will tell you the distance from the tip of the tool to the underlying surface metal. The greater the number, the more crap on your panel between the gauge and your car. Obviously it only works on metal panels.

Like Bill mentioned, you'll want an etch primer as a bare minimum. I would sand down to bare metal in all the areas that have holes and clean out that rust first. You want to be sure the rust hasn't developed into rot that might have enlargened the holes. If it has done that, it can be fixed with a person with some welding skills, hopefully it won't be an issue though.

Try to get the front and back side if you can. This would involve taking the fenders off and removing a bit of the interior, admittedly a pita. Clean up the outside first and see how it looks, but I bet there's a good chance you'll find rust on the inside.

The etch primer won't be a pretty fix, but it is a necessary one unless you can start doing the repair right away.

Getting the inside of the rockers would be more than a little difficult. Stop at an Oreillys or other parts store that sells paint to local body shops. Ask them for a protective spray for inside frame rails. It'll be a waxy substance that can be sprayed through small holes to cover the inside. This will provide a barrier to halt the rust inside the rockers.

BTW, you mentioned seat belts. I'm one of those people that would replace the whole set. Our mustangs are old enough for the fabric of the belt material to have at least begun to dry rot. It'll cost about $500 to replace them, pricey, but they do serve a pretty important purpose.

billison said:

Dave. What do you suggest for a good paint protection. Fresh paint, gonna wait till the 90 day mark and start buffing and waxing or ceramic coating or whatever, just looking for some guidance

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Obviously nothing for the first three months as the paint begins to harden and also release the solvents from spraying.

Anything on it during that early time will seal those solvents in the paint leading to a shorter life span.

Use a gentle soap like Dawn to wash it and CLEAN soft mitts or rags.

After that use a natural wax like a carnuba type.

Solvents will still be released for up to a year after the paint job.

Here's a value oriented clear that I highly recommend.

The shop cost is roughly $123 per sprayable gallon. Your cost won't be a lot more than that.

It sprays beautifully and has a lifetime warranty.

Steel1 said:

Hey Dave,
Looking to set-up an air filter system for spraying primer/paint/clear.
Doesn't need to be anything super complex, not spraying full cars just hoods bumpers etc.
Would something like this from Eastwood work ok for a hobbyist ?
https://www.eastwood.com/rockwood-3-8-npt-2-stage-air-filter-dryer-system.html

Also the last bumper I painted was sealed with a Tamco sealer (autobody101.com)I think you're on that site.
I was impressed with it and the pricing is very reasonable, they also offer a line of primers and clears.

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That filter would be great for what your needs are. Though if you intend to spray a larger area (like the whole vehicle) you'll want to make some water traps with drains prior to the filter.

If it's a high humidity area where you live, it's even more important for the water traps.

I've never shot Tamco products, so I really can't offer much on it.

Tamco says the sealer is a direct to metal product. Assuming they know what they're doing, that makes one less step. Though I kind of worry about their claim of direct to plastic ability.

They're combining lots of abilities in one product. Sometimes in order to do that, it's not as durable as dedicated products, such as a dedicated plastic adhesion promoter, or an etch primer.

But, it could be fine. I don't know their products well enough.

Sorry about being so vague on that point.

CarMichael Angelo said:

Hey look..me posting a paint related question in a paint specific thread.

I'm priming my hood and trunk today. Hopefully without covering the thing in orange peel. Especially considering that I'm doing the undersides, which will be a sonofabitch to sand smooth if this happens.

I'm using Marhyde 2k primer. Mixed at 4:1. I'm using a 1.7 tipped gravity feed gun that I've always used in the past for this purpose. It's presently in the mid-high 70's working its way up to about 90. The activator is a mid temp ( 70-80) degree product.

What is the proper procedure/pressure to insure I don't cover these pieces in a ton of work to fix?

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Honestly Mike, I’m not sure why you have the peel so badly.

You’ve probably already shot it, if not, I can give you a call?

lemosley1973 said:

I have a Kia Soul with some plastic trim on the outside along the a pillar. Is there some sort of super tape used by the OEMs to stick this stuff on?

The trim piece appears to be warped a little to - is there a way to get it back into shape - baking it a bit, heat gun, etc?

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Use 3M two sided tape.

You’ll want to pick up a couple adhesion promoter wipes to use on the panels before putting the tape on. Just be sure to put the tape exactly where you want it. It’s a bear to take back off.

The tape by itself won’t do a very good job.

Post a picture of the part and it’s warpage for me please.