Industrial Adhesives I am asked by Maintenance departments responsible for maintaining the hot melt glue system on what procedure do I recommend for cleaning the build up of hot melt char. The following are my thoughts on the subject with the key being for optimum performance of the hot melt units, cleaning should be performed on a routine basis.
1) Supply hoses to the applicator heads should be disconnected and the old molten adhesive pumped out into a container that will not melt from the heat. Set the tank temperature at 250F degrees.
2) Turn off the tank pressure, disconnect supply hoses and cover ports. The supply hose ends should be placed in a heat resistant container
3) Fill the melt tank with either a solid (paraffin wax) or liquid (mineral oil) which will be the cleaner. Maintain pot temperature below the flash point of the solid or liquid being used
4) Allow the solid or liquid to cook for 2 to 3 hours.
5) After the 2 to 3 hour time frame, drain cleaner into heat resistant container and wipe the sides, bottom, and strainer screen with lint-free cloth. REMEMBER: wear thermal protective gloves to prevent burns.
6) Replace output filter, reconnect supply hoses to the tank, and fill the tank with fresh hot melt adhesive.
7) Heat the hot melt adhesive to 250F degrees, and when fully melted pump the adhesive through each supply hose into a heat resistant container until the adhesive is clear of any char.
8) Replace any worn supply hoses and reconnect hoses to cleaned or new applicator heads. Also replace line filter where necessary.
9) Set the tank, hoses, and applicator heads to the recommended application temperature of the hot melt adhesive, fill the hot melt tank with adhesive, and allow the hot melt adhesive to completely melt before using.
NOTE: Always consult the equipment manual for specific instructions as it relates to equipment cleaning and maintenance of hot melt gluing systems.