The phrase "glue factory" refers to a place where horses are sent to be turned into glue when they are no longer useful or able to work. Full definition
The two adults impart life lessons, but Charley is more attached to Pete, a five - year - old chestnut quarterhorse who is due to be sold to a Mexican glue factory once he can no longer race — which looks to be soon. (thestar.com)
As the threat of sending Pete to Mexico looms closer (will there ever be a horse movie made that doesn't hinge on the omnipresent fear of pony meeting figurative glue factory?) (theglobeandmail.com)
Glasgow «To Beat Edinburgh» as No1 Film Festival The Scotsman; February 21, 2014; Ferguson, Brian; 700 + words... Connell, film - makers Terry Gilliam and Jason Priestley, Turner Prize - winning artist Douglas Gordon and French fashion designer...food - themed screenings and pop - up cafes, and an old glue factory - which will be turned into an amusement arcade for the festival... (highbeam.com)