Hot melt glue gun safety at work.

This guide is for industrial hot melt guns that take granulate, pillows, 43 mm sticks or cartridges, such as Reka. Your adhesive’s safety data sheet and the gun’s operating manual always come first.

A hot melt gun is a simple tool, which makes it easy to get casual with it. The glue leaves the nozzle at up to about 200 °C (some guns go higher), it sticks to skin, and it keeps its heat. Safe use comes down to a few habits, and all of them are easy to build.

Before anyone uses the gun

• Trained people only. The gun should only be used by trained, instructed and authorised people. A short handover when a new operator starts covers it.
• Read the adhesive’s safety data sheet. It gives the working temperature, what the glue gives off if overheated, and what protection it needs.
• Protective gear. Wear heat-resistant gloves and safety goggles.
• Check the gun. Do not use a gun with a cracked casing or a damaged cable.
• Route the cable and air hose. Lay them where nobody can trip over them.
• Clean, dry air for air-driven guns. Use compressed air at 2 to 6 bar, from a compressor with an oil and water separator. Never more than 6 bar.

While you work

• Nozzle down, always. Never hold the gun level or nozzle-up, and never lay it on its side while the glue is liquid. Glue runs into the vent valve, and a blocked vent can let glue escape even when the gun is off. See glue gun dripping.
• Park it properly. Between jobs, put it on its stand, wire stand or magnetic plate, or hang it from a spring balancer. No overhead work.
• Never point the gun at anyone.
• Never pull the trigger on half-melted glue. Wait for the glue to melt fully; forcing it damages the gun.
• Spray guns (TR 60 LCD, TR 80 LCD). Keep the spray cap hand-tight only, and never turn off the spray air while a spray cap is fitted.
• Do not leave a hot gun unattended.

Keep the temperature right

• Never go above the working temperature. Keep to the one on the adhesive’s datasheet. Overheated glue breaks down, can harm health, and leaves brown flakes that block nozzles.
• Turn the temperature down in long breaks.
• Know the warning signs on air-driven guns. Shut the gun down at once if the temperature drops to 130 °C and then climbs again, or if an LCD model shows 2.5.9 and blinks. Both need a qualified repair; send the gun in.
• Stop an MS gun that leaks. If hot melt leaks out of the casing, stop using the gun immediately. The piston O-rings are worn and the gun needs a repair.

Changing parts and clearing faults

• Unplug first. Change a nozzle only when the gun is warm and empty: around 60 to 80 °C on air-driven guns. See changing a nozzle.
• Expect hot glue to escape. Vent and lid work carries a real risk of burns from hot adhesive. Empty the gun first and wear your gloves and goggles.
• Open the lid only when the gun is warm. Close it without over-tightening.
• Change only what the manual allows. That is the nozzle, the lid and the vent-valve parts. Anything more is a repair: send the gun to us, because self-made repairs void the warranty.

Cleaning: never with solvents

Never clean the gun with benzine, benzene, toluene, acetone, turpentine or similar solvents: there is a risk of explosion. Normal hot melt left in the gun simply remelts next time, so the gun usually needs no cleaning. For PUR and for polyamide glues, which can need a proper cleaning agent, see cartridges and refills or ask us.

If hot glue touches skin or eyes

• Skin: cool the area with cold water at once. Do not peel the glue off. See a doctor if needed.
• Eyes: rinse under running water for about 15 minutes and see a doctor at once.

Keep a first-aid box and a clear route to cold water near every gluing station.

Storing and disposing of glue

Store hot melt sealed, in a cool, dry place away from heat sources: see storing hot melt adhesive. Dispose of waste glue as your local rules require.

A short checklist for the station

1. Gloves and goggles at the station.
2. Stand, wire stand, plate or balancer in place: the gun is never laid down.
3. Working temperature from the datasheet written on a label near the gun.
4. Cold water and a first-aid box close by.
5. No solvents anywhere near the gun.

Related: how to use a hot melt glue gun · glue gun care and maintenance · troubleshooting.