Tutorial for painting a chassis

Here is a tutorial in which we present all the specificities of the techniques applied to the painting of a chassis, whatever it may be, whether an automobile, quad, motorcycle, ULM or other chassis. Here are the main steps that must be followed to paint a frame, as well as the tools and products that we recommend. In particular, we will see the best options and the different choices that are possible regarding the final painting of the chassis.

Tutorial for painting a frame in 3 steps

Step 1 ► Preparing the support
Step 2 ► Applying a primer
Step 3 ► Application of the finishing coating

Tools and consumables
♦ Sander
♦ Paint gun
♦ Abrasive sheets
♦ Abrasive sponge

The products needed to paint a frame
♦ Degreaser
♦ Aluminum putty
♦ Primers for specific metals*
♦ Finishing coatings*

How to paint a chassis?

Step 1 ► Preparing the support

A chassis is a metal frame which constitutes the central frame which supports the bodywork, the wheels, the engine, etc. It is important to preserve the very nature of the material which constitutes this essential supporting structure, with priority treatment curative and preventive treatment of oxidation.

Strip or cover
You have the free choice to remove the existing covering on a frame or to cover it.
To remove the old paint, there are the following solutions:
→ chemical stripping with a stripper
→ sandblasting, shot blasting

For an automobile chassis with paint in good condition, it may be perfectly possible to cover with new paint, to increase the thickness of the protective layer and thus effectively protect the metal chassis against corrosion.

For a visible frame, which you wish to paint and color, with a visually attractive paint and if you are ready to undertake this important work, then it may be wise to choose stripping or sanding.

Chemical stripping

We use a powerful stripper, which we apply either with an aerosol or with a gun. You must let the product act and dissolve the paint. Depending on the age and thickness of the paint, it is often necessary to repeat the operation with several coats of stripper. The paint residue can then be cleaned with a high-pressure cleaner.

The entire exposed frame must be degreased with a degreaser or solvent, using an abrasive sponge and absorbent paper.

Examine the condition of the paint

In the case of application directly on top of the old paint, a careful examination of the old base should be carried out to look for areas of paint in poor condition. Cracked, loose or fragile paints must be scraped using a wire brush or spatula. The entire surrounding area should be sanded down to the metal.

It is essential to look for all the starting areas of corrosion. This disease from which metal suffers can develop even after being repainted and covered. It is important to remove all rust areas by sanding.

Repair the chassis

Welding work can be carried out and small repairs with putty can be made if necessary. On metal frames, aluminum putty is used.

Sanding and degreasing

If the metal frame is bare or if it is painted, in both cases, it is imperative to sand with P320 paper in order to ensure and guarantee perfect hold of the primer or paint that is planned to be applied. 'apply.

After sanding, the surface must be cleaned, in particular with a degreaser to remove all contaminants which may be invisible to the naked eye, and in particular greasy residue.

Step 2 ► Applying a primer to the chassis

This primary layer has a dual function: it can stick to bare metal and it protects the metal against corrosion.

The primer therefore has an adhesion and also a protective function. There are primers which have a general function, which allow hooking and leveling, but they are not specific primers and therefore their effectiveness in terms of protection is much less.
It is better to superimpose two types of primers if you want to level a frame.

⚠ There are ferrous and non-ferrous metals: for each of these two types of metals, the same primer should not be used:

AS801 primer for metal: it is a primer available in white or black, very effective on all ferrous metals such as steel. It is applied in 2 coats and dries very quickly.

P714 aluminum primer: it is a “WASH” type primer which is effective on many metals and which is mainly used on aluminum. It also exists in white, gray, or black. It is applied in two coats and dries quickly.

BESA F294 primer: it is a high performance two-component primer for industry. It is ultra effective thanks to its epoxy formula on most metals and it protects metals sustainably against the most extreme wear conditions.

Drying and covering the primer

It is recommended to wait for the primer to dry completely in order to continue with the rest of the work. Once the primer is completely dry, it will continue to harden and adhesion will gradually increase over time, reaching a maximum level after several days.

Before you can apply the final coat of paint, you must sand the primer. Indeed, it is not possible to paint a paint on a primer, without first having created the necessary conditions for good adhesion.

→ Sanding can be done with P400 or P500 abrasive paper or a green abrasive sponge. Immediately after sanding, clean with degreaser and a clean cloth to remove fingerprints and sanding residue.

Step 3 ► Application of the finishing coating

There are 3 main options for achieving a very beautiful frame painting.

Option 1/ direct gloss paint: the beauty option

This is a very resistant glossy finishing lacquer. This product is supplied as a complete kit, that is to say with a lacquer, a hardener and a thinner. It is therefore a two-component polyurethane product.

It is a high quality finish, usually used on truck bodies and also all older automobiles. This type of paint ensures a very long lifespan and perfect protection of the chassis against all splashes of water or products, but also against cold or heat, but also abrasion.

These paints, which are called “direct gloss”, are easily applied using a spray gun. Application is done with two coats sprayed 10 minutes apart.

There is an even more resistant version (2C polyester polyurethane) which we offer under the name Hi-Gloss black lacquer.

There is a black and white version in a 2C pot or aerosol and also a version that we can color according to any color from the RAL or PANTONE color charts: this is the PU color lacquer on demand.

Option 2/ the RAPTOR: The resistance option

Here is a unique product of its kind, ultra resistant, ultra thick, which is usually used for chassis but also for painting 4x4 dump bodies.
The RAPTOR coating is black in color and its thickness is so great that it requires a Blaxon type gun to be sprayed. It is a two-component epoxy type product. It comes in a complete kit which makes its use practical and easy.

In addition to its remarkable strength and durability, it is a product that sticks almost everywhere and allows you to apply an extraordinary thickness of several millimeters without any risk of sagging.

We offer the RAPTOR in a transparent version, which allows you to tint it in the color of your choice thanks to our concentrated tints.

Option 3/ Special effect finishes: the “Custom” option

When painting a Quad, a motorcycle, or any type of machine on which the chassis is visible, then it is possible to integrate the decor of this chassis with the painting of the fairings.

This means that it is possible to apply pearlescent paints, metallic paints, Candy paints or even chameleon or fluorescent paints to the tubular surfaces of the chassis. Here is the process:

A/ Background
It is necessary to have prepared the background carefully, with the application of a primer (either white or black) depending on the special effect paint that is planned to be applied and sanding with P500 paper.

White background: fluorescent paint, light or bright pearlescent paint, phosphorescent paint
Black background: chameleon paint, metallic paint, dark pearlescent paint

B/ Painting
The paint is applied with a spray gun in several layers, until the background is covered and the optimal color is obtained. The gun must naturally be set with a tight jet in order to save paint.

It is very important to proceed to the varnishing stage before the paint has completely dried, in order to allow good cohesion of the two layers, which is essential for a frame.

C/The varnish
The varnish helps protect the paintings and also makes them shine.
We use a 2C acrylic polyurethane bodywork varnish.
It is advisable to follow the instructions strictly limiting yourself to the two gloss coats recommended for most varnishes. It is not advisable to apply more layers and apply a lot of thickness to the frames, because the more thickness there is, the greater the risk of cracking and delamination in the event of an impact.

The chassis may be subject to more projections and shocks. It may be wise to add a very small percentage of flexibilizing additive to the varnish. A varnish that is too hard may be more susceptible to the risk of cracking, while a softer varnish will have a greater capacity to absorb shocks without cracking.

Don't forget that our technical department is at your disposal to answer all your questions (tech@Stardustcolors.com).

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