The opposite of harden is soften.
The opposite of soften is - harden
Soften.
It will harden a stool
no
A plastic which will soften when heated and harden when cooled.
carbon,
'Glue' is too general a term for that question. -What makes some glues soften will make other glues harden. -Please be specific about which 'glue' you mean.
A macaroon is actually classed as a cake, because when cakes go stale they harden, but biscuit soften when they go stale!
Depends entirely on the glue. some harden in water, some soften or even dissolve.-Name your glue -
Cocoa butter can harden due to temperature. If it is hardened, and not just dried out, you can warm it a bit. It should soften back up.
It helps to cool the steel which, if it gets to hot, will soften and loose its edge.