Undercoating Guns

Undercoating Guns for Stone-Chip & Body Protection Coatings

Undercoating guns are pneumatic application tools designed for higher-viscosity automotive body protection materials such as stone-chip and selected underbody coatings.

Unlike conventional paint spray guns, these tools are designed around heavier protective coatings and the containers commonly used for underbody and stone-chip products.

The range includes Walmec undercoating and cavity-protection guns together with a specialist application gun for Cobra protective coatings.

What Is an Undercoating Gun Used For?

• stone-chip coatings,
• compatible underbody protection materials,
• textured sill and wheel-arch coatings,
• selected cavity wax systems with suitable accessories,
• specialist heavy-duty protective coatings where approved.

Always confirm compatibility between the coating, container and application gun.

Undercoating Gun vs Paint Spray Gun

A conventional paint spray gun is designed for fine atomisation of primers, basecoats and clear coats. An undercoating gun is intended for substantially heavier protective materials.

Stone-chip applications can also require a controlled textured finish rather than a smooth paint film, making the correct gun and setup important.

Underbody Protection Gun

Many bulk underbody coatings are supplied in containers intended for connection to a suitable UBS or undercoating gun.

Container thread, coating viscosity and gun design can vary, so do not assume universal compatibility between every one-litre coating container and every gun.

Cavity Wax Gun & Probe

Some undercoating guns can also be used with cavity protection materials when fitted with the appropriate head or extension probe.

Cavity application requires a different spray pattern from heavy underbody coating because the aim is to distribute a low-viscosity creeping material throughout enclosed body sections.

Interchangeable-Head Application Guns

An interchangeable-head gun can provide greater versatility where different body protection materials need to be applied with the same basic tool.

Always use heads, probes and coatings approved for the individual gun model.

Metal or Plastic Undercoating Gun?

Both metal and polymer-bodied application guns are available. Selection should be based on construction quality, intended frequency of use, coating compatibility, available accessories, cleaning requirements and ergonomics.

Material alone does not determine whether a gun is suitable for professional or occasional use.

Air Pressure & Compressor Requirements

There is no universal pressure setting for every undercoating gun and coating.

The required setup depends on gun design, coating viscosity, desired texture, nozzle configuration and available compressed-air supply.

The compressor must be capable of supplying both the required pressure and sufficient air volume during continuous application.

Adjusting Stone-Chip Texture

The final texture can be influenced by air pressure, application distance, material viscosity, gun design, film build and gun speed.

Carry out a test spray before refinishing visible surfaces or attempting to reproduce an existing factory-style texture.

Cleaning an Undercoating Gun

Clean the gun promptly after use before the coating dries or chemically cures inside it.

Use only a cleaning product compatible with both the coating and gun materials. Keep the material tube, nozzle, threads and interchangeable heads free from cured coating.

Safe Use

Pneumatic spraying of stone-chip, underbody and cavity coatings can generate airborne aerosol. Follow the coating safety data sheet and use the specified ventilation and respiratory, eye and skin protection.

Operate pneumatic equipment only within its specified pressure range and do not use damaged hoses, connections or application tools.

Frequently Asked Questions About Undercoating Guns