@Arlathina Time is the resource I have a limited amount of. Between work and class, I have notable little free time. I uninstalled League of Legends to remove one distraction from my class work. That leaves this, which really isn't so bad since most projects I can just "start and leave", and of course my friends that I need to avoid cut down on seeing while classes are up - which is the harder part. I'm stateside in a small red mapdot, and I've got a buddy in Japan tossing out news about expecting and his recent rank-ups in the Airforce, I work with two other friends, one friend actually let's us use his (and his wife's) house to party... yeah. Anyway, time is the factor!
@Damien Kriez Thanks for understanding. If you feel I'm being particularly harsh, ask just about anyone how my standards are set. In your case, you're not terribly far off; I just really want to see more of the character and less of what the character tries to be. Failure is human and limitations are natural. Group Five is actually a team of antagonists. I'm not quite sure where your character will fall at this point. Group Three is full, Group Four requires a Firebending Master (I think it's covered anyway). We may need to hold out until I get Group Six on its way.
@GonzoB. The issue with your logic there is that the reason sand explodes so violently is either a) inconsistent heating throughout the glass causing stress on the material b) compression of the material causing breakage or c) inconsistent melting of constituents of the glass. None of those are results of reliable issues that a Sandbender with Lavabending could manipulate. Additionally, the point of heat for lava and for glass is actually significantly different. To create lava with the relative viscosity Bolin had, depending on the rock, it would need to be around 1,200C minimum while glass barely gets workable at 1,800C; I've failed to find source material that reliably tells me the viscosity of pure silica glass. The reason for that is simple; pure sand, ie silica particles, actually have such a high melting point and transitional heat prerequisite that other materials are often mixed in. The key to earthbending is the purity of materials, so in this case, mixing in materials to the sand to lower its heat would make it harder to bend.
When I was referring to its change in state, I meant its literal change in atomic structure. Pure Sand is an amorphous liquid that loses its crystalline structure - the structure it had even as sand. It literally stops being a true solid and a true piece of earth at that point. Bolin controlling lava is him controlling liquid earth; that's rock in another physical state. While I could see the stretch here, the fact that the change in rock isn't permanent while the change in glass is leads me to think that it shouldn't transfer over. Not to mention, the original prompt was "can we recreate explosions" and we really can't. We could make glass shrapnel through time-based glass bombs because even if you could superheat in theory (nearly double the heat needed), a bender would lose control over it once it changed. That still isn't the type of explosions we were looking for, at least through my imagery, nor are they reliable or something the bender would have control over when truly went off.
Literally, look at the steps and requirements here. First, a character has to be both a sandbender and a lavabender to be a glass bender, but more over what we imply he can control:
Control over Sand ---> Transition Sand 2,000C+ into glass ---> Control over an amorphous liquid, ie grey zone technicality ---> Control over internal heat and density of glass
The other note is that if we allowed control over glass, would he be able to bend man-made glass? That's to stop him from just ripping out windows from dozens? I would say the fact that most glass, even in the Avatar Era, would likely be a mix of at least three constituents, but the question stands: could he manipulate glass that was solid? If so, how? Does he get to manipulate it like Kuvira metalbended the space metal? Or, does it have limitations? Can he reheat it to make it reattain its malleability? If so, to what degree and would it become red hot again? If he could, reheating glass is - which is inherently temperature resistant - is a whole different ball game as its lack of crystalline structure as well as other physical properties greatly increase its melting point. That's why glass recycling, although cheap and effective, is done with bulk and given more constituents that are later removed to lower heating.
There are so many factors here, so many technicalities, so much actual physics involved, and the fact this doesn't really result in the desired effect we were after. Even if someone just wanted a glassbender, it would be insanely complex to such a degree it wouldn't fit the "traditional" or 'spiritual" aspect of the roleplay I originally tried to create. I think even if this got by every minor technicality, it'd be too much work and imply someone with as much finesse and control of Earthbending as Toph. There is essentially one plot element I have that would justify this, and I may use it later, but I still don't see this "naturally occurring"