ONLY COPPER, BRASS, ALUMINUM SHOULD COME INTO CONTACT WITH GLUE
The advantage of using copper, brass, and aluminum in glue-room appliances, due to their self-cleansing properties, already has been mentioned.
In apparatus designed for melting glue the use of copper, brass, and aluminum is absolutely required for economy and good results. Copper, brass, and aluminum are the only materials available that are not affected unfavorably by the action of acids in glue, steam and water; by boiler compounds, dirt, pipe-rust and sediment.
An iron agitator or stirrer in a glue-heater is corroded so quickly by the acids in glue, water and steam that in six months it is unfit for use.
A brass agitator, on the other hand, will last practically forever. So it is with every part of the glue-heater with which glue comes into direct contact.
The glue user who has had experience with galvanized iron heaters does not need to be told that the iron quickly is eaten away and the apparatus rendered unfit for use. It is certainly the part of wisdom to invest in copper, brass, and aluminum equipment, to which metals there is practically no “wear-out.”
Glue-room equipment of iron is still sold, but only because there are still some users who are so blinded by the initial small saving in outlay, as not to see the saving that accrues in the end from using indestructible materials—and the additional saving due to good work and economy of glue.