What kiln?
The plastics used in DIY 3D printers generally have a melting point around 200c
Glass melts around 1400c
That can have a very negative impact on electronics and mechanicals.
And it has a very wide temperature / viscosity range.
If you've ever formed glass by hand (and I suppose you have), you know what that means - it will "slump" on you at any moment, without warning.
It sort-of gets tired of being handled and lays down on the job.
The art of hand formed glass takes decades of apprenticeship for a good reason.