Daily Archives: February 7, 2012

Once more … from the top

Yesterday we started working on this hood from a Mitsubishi Eclipse. The hood had been repainted in the past and the paint was cracking and beginning to peel. Because the paint was failing we couldn’t paint directly over the existing paint, requiring us to start at the top.

The first step was removing the cracked and damaged paint. Normally I like to paint over paint when I can because the paint already on the car provides a beautiful smooth surface to start with. But when the paint is failing, as on this car, painting over the top of it is a waste of my time and the customers money.

The first two pictures show the hood in the messy part of this job … removing the old paint. The process starts by the application of a strong paint remover to soften up the paint. After the paint has soaked for a bit the paint begins to bubble and loosen from the surface. It can then be scraped off, leaving the bare metal beneath. It is a dirty, stinky, messy process, but it is the only way to turn out a quality paint job when the paint is this far gone.

Yesterday we removed the paint. Today … we put it back. The next two pictures, numbers three and four, show the bare metal hood in the booth, ready for the painting process. The mottled appearance is from the galvanization process and the fact that whoever repainted the hood the last time appears to have removed the paint with a grinder. A definite no-no.

After the hood was placed in the booth, we carefully cleaned the hood with our wax and grease remover to remove any residue from the paint remover and the oils from our hands after handling it.

The next step was the application of the etching primer. You can see the hood after the etching primer was applied in the fifth photo. The slight golden hue is the distinctive color of the etcher that I use.

The etching primer’s purpose is to bond to the bare metal, to provide a layer of protection from moisture and rust, and to give the layers that follow a good bonding surface. Like nearly every other paint, automotive paint won’t stick well to bare metal unless a primer is used. The etching primer is just the first of several primers used to provide the long lasting finish people expect.

The sixth and seventh photo is the hood after the the application of the next primer … the urethane sealer. Once the sealer dries it forms a tough, waterproof seal that protects the metal from rust and minor dings and abrasions. The etching primer and the sealer work together as a system to form a rugged, long lasting layer of protection for the metal beneath.

The sealer comes in one of seven shades of gray … from very light to very dark. Light color paints generally use the lighter shades of gray, the darker colors use darker. Each paint color specifies one of these seven shades of gray to reproduce any given color. Because the sealer is very good at covering and hiding any color changes in the primers below, the paint has a very uniform color when it is applied and can be reproduced time after time with near perfect matches in the color.

The next two photos, pictures 8 and 9, show the hood after the application of the base coat. The base coat, the color layer of the two stage paint process we use here at JMC AutoworX, provides the color. It is applied in several very thin layers to provide full coverage, but at the same time, avoid runs. The base coat dries to a dull, nearly flat finish, which is why the reflection in the paint are so blurred. In fact, the only reason there is any reflection at all is because the paint is still slightly wet. When it is completely dry it will be nearly as flat as a chalkboard.

The final two pictures show the same hood after the clear coat is applied. It makes quite a difference doesn’t it? The paint looks deeper and richer, and the reflections go from fuzzy and distorted to to crisp and clear.

Not only does the clear provide the pop to the finish, it is also the first line of defense against the elements. Where the base coat, the color, is applied very thinly, the clear is put on much thicker and dries to a tough, hard to damage surface.

So there you have it … painting a car from the top to the bottom. Or perhaps, more accurately, from the bottom to the top.

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