Extruders - dos and don'ts

Hand-held extruder guns are commonly used to rapidly fill a hole or skive with raw rubber compound during tyre repair. Used correctly, they save significant time over hand-layering but get the technique wrong and you'll damage the gun and compromise the repair. Here's how they work, plus the do's and don'ts every tyre repair professional should know.

How Extruder Guns Work

Uncured rubber compound, formed into a long continuous rope, is fed into the pneumatically driven worm drive mounted at the front of the gun. The compound is warmed enough to reduce its viscosity, but not enough to start the curing process.

Under high pressure, the warmed compound is then extruded out of the end of the gun and directed into the skive. Because the rubber is forced out under pressure, no air bubbles get trapped  a critical advantage for repair quality.

The result is a much faster, cleaner fill than layering up rubber strips by hand, with significantly fewer voids or weak spots in the finished repair.

The Do's

1. Pre-heat the gun for 5–10 minutes before use to allow full and even temperature along the working section.
2. Mount the rope rubber container close to the work area and ensure the rubber is spooling tangle-free.
3. Keep the rubber off the floor and clean from contamination — dirt and grit damage the worm drive over time.
4. Remove all excess rubber from the worm drive after use. Residual compound is the leading cause of premature failure.
5. Flush A+B compound with regular rope rubber after use. A+B styles harden if left inside running standard rubber through clears the system.
6. Lubricate after cleaning. Add 5 ml of air tool lubricant to the drive and run the gun for 10 seconds to spread the oil.

The Don'ts

• Don't use the gun cold. Forcing cold, viscous rubber through the worm drive at full pressure causes serious wear and inconsistent extrusion.
• Don't let A+B compound cure inside the extruder. Once it hardens internally, the gun has to be stripped and cleaned at workshop level.
• Don't leave residual rubber between sessions. Even regular compound becomes harder to clear if left overnight.
• Don't run the gun dry. Operating without lubrication causes rapid internal wear and dramatically shortens service life.
• Don't force a blockage with extra pressure. If the extruder jams, stop and strip it. Forcing it damages the worm drive and seals.

What to Look For in a Professional Extruder

When choosing an extruder gun for tyre repair work, the key specifications to compare are drill power, heater output, maximum temperature, weight, and rubber throughput. Two common professional configurations look like this:

Heavy-Duty

Mid-Range

Heavy-duty configurations suit high-volume commercial repair shops dealing with OTR and truck tyres. Mid-range configurations are lighter and more manoeuvrable, well-suited to general workshop use where portability matters more than maximum throughput.