leave body panels off to paint?

[ampsman]

So i am gonna make my first attempt at painting and have the first of many questions. I have the front fenders, hood, bumper, etc... all off the car right now, should i leave these off and paint them all seperately or should i put them all back on the car before i paint?

[Ed]

The benefit of painting the panels while they are off the car is that you get paint on all sides, providing additionaly protection against rust.

If you had the pieces in primer then re-assembled you would end up with only primer to protect those spots that you could never wax.

On the other hand painting the car while it's assembled means there is less of a chance you will ding or chip the paint when you re-assemble.

[hls30.com]

The new issue of Autorestorer has a discussion of this very subject, and some great paiting tips.

Will

[EScanlon]

From what I got taught, many years ago, when painting a METALLIC paint, you ALWAYS want to paint all panels that are contiguous on the car at the same time and at the same angle. The easiest way to accomplish this is to paint them ON the car. The reason given to me is that metallic paint will readily react to the static electricity you generate as you paint and will let the metallic flakes "align" themselves according to the charge. It may sound like a lot of hogwash, but having seen a fender shot away from the car, up against a door that was painted ON the car, and you could readily see the difference in the metallic shine.

Plain color (i.e. non-metallic, pearl, or candy) as long as the conditions are the same when you paint (temp, humidity and number and thickness of coats), should look fine against one another, as long as the paint is from the same batch.

Thoughts anyone?

Enrique

[hls30.com]

When I have sprayed metalflake, I shot the cars twice, once off the car for total color change coverage, and once when the panels were back on-after color sanding, to keep the deposit angle of the flake aligned-just as Enrique pointed out. The two covers actually made the paint appear really "deep", and massively slowed down the fading of light blue(fades the worst).

Will

[EScanlon]

When I have sprayed metalflake, I shot the cars twice, once off the car for total color change coverage, and once when the panels were back on-after color sanding, to keep the deposit angle of the flake aligned-just as Enrique pointed out. The two covers actually made the paint appear really "deep", and massively slowed down the fading of light blue(fades the worst).

Will

Here's a perfect example of differences between bodyshops and bodymen. When I do a complete color change, I shoot the sills, engine compartment and other places that must be shot to do a "complete" color change first. These are shot to full color and gloss.

Then, prior to shooting the exterior, I mask off the edges that would allow overspray to attack those now finished areas. I will have also sanded any overspray on the exterior and prepped the edges to receive a second coat of paint.

Although the color sanding on a metallic paint job will increase the gloss and "depth" of the look of the paint, I've not had that many instances where it has really shown to be worthwhile. Many jobs the "customer" (I don't hire out.) is more interested in returning the vehicle to use and would not notice the slight difference. On those jobs where I've had a definite requirement of smoothness, depth, gloss, or .... I've even gone as far as shooting three times with sanding in between. Then again, the job depends on whether you're using lacquer or enamel as the two are worked differently.

Enrique

[hls30.com]

I didn't give a primer on car painting becaouse I the article on Parts Edging in Autorestorer I referenced addressed the original question posed in this thread, whether to leave the panels off or reassemble to paint. Check outy the article, it nails the question!

Given proper masking techniques, it has been my experience that shooting any light color low pigment translucent metal flake or pearl paint will respond wonderfully to the multi layer process, Each layer(starting from a different location on the car) has the suspended reflective particles oriented a different direction, creating several times more "action" or "electricity" in the paint with out adding the distraction of actually seeing the flakes(like looking at a .41 dot pitch monitor instead of a .24 dot pitch, thje picture is the same, but the eyestrain is completely different) The more action is in the paint, the more a huge difference is clearly made-unless the process is not done correctly The gloss benefits from the color sanding, but the transparent layers of suspended reflective surfaces is what really livens up the paint, and allows it to fade without affecting a color change as noticeably, or as quickly.

Shooting paint that is a solid color with a high pigment density the same way is pointless. It is like a front surface mirror, there is no depth.

When I want to shoot a dark color with metal flake or pearl, I shoot a base color coat first, then for a second coat, thin out the base color substantially with clear, mix in the additives, and shoot-atleast one more coat. This process brings out a depth unachieveable any other way-regardless of the paint system used.

The key to the depth is the clear-even 1 coat will do, but, the key to the "electricity" is the layers of the reflective additives all slightly colored by the low density of the pigmnet layers in the paint.

Will

PS. if we all did everything the same way, there would be no differences in our cars-or us-what fun would that be?

[GunnerRob]

The benefit of painting the panels while they are off the car is that you get paint on all sides, providing additionaly protection against rust.

Has anyone coated the inside of the removable panels with something like Por-15? I've thought of doing this to the inside of the fenders and such. I'm VERY aware that the rust monster attacks from the inside out and I'd think that taking this approach would improve the surviveability of these pieces (or any surface that is not painted).

[beandip]

Yes , I painted POR on both the inner fender and the inside of the front fender , the same for the head light buckets and surrounds. I shot POR inside the rockers and inside the doors and rear hatch and doglegs as well as the rockers and all other surfaces that are not exposed like down in the cowl and the back of the cowl cover. Just dont get it on the outer surfaces or where you are going to want color when you go to paint. I did some surface rust repair in the battery area and used por there also so I shot the engine bay with ticoat primer so the color coat would stick when painted. While I was at it I primed the cowl with ticoat also.

[hls30.com]

What Gary said!

Will

[mriz]

For what it's worth I did coat the inside of the rockers before welding, and after I filled a 20cc syringe with rust mort and shot into the holes where I drilled for the scuff plate. I hope this coats any oxidation from the welding .Time will tell if it works.