@toxicitzi  
Ah, the episode that was to actually have spike save the crystal empire from something (because he’s wrongly attributed as the sole hero, when his useful moments were outside the eyes of the crystal ponies and Cadance did far more) and turned into seeing if they could make Spike a buttmonkey for 20 minutes.
 
Lets also throw in how idiotic the plot setup was, the extremely stupid chain of events that were allowed to happen for the cloud glacier to even appear, the extreme stupidity of it being something “only spike could solve” by gimping the entire freaking cast, and the general fact that the animators and writers don’t see spike as anything more than a catastrophe magnet to use throwaway lines and pratfalls on.
 
You really think anyone involved with that episode cared what his fire color was by the time they got to the end of it? No, everyone just wanted the accursed episode to end, same with the animators.
 
We now know dragons have color coded flames, as Started with Spike and his green flame, and now Ember with her fuchsia flame.
 
 

 
Spike’s green flame also has an interesting twist to it; the core of it is white.
 
Also, Green flames are not temperature based, they are based of the gases released while burning.
 
Specifically, Borax, Boric Acid, and copper sulfate. If anything, the fact that some of these elements are used in flame preventative materials simply tells me that his insides are coated with the stuff so as to not self combust.

Jet fuel Dragon breath can’t melt steel beams iron locks.

@Kryptid  
What I said wasn’t entirely sarcastic. I don’t know the English word for it. :j

@thps48  
Sarcasm can be difficult to detect through text alone.

@Kryptid  
One’d have to be comatose to not know I was joshing. :T

@thps48  
He does sweat:
 

@Kryptid  
I’d presume because he’s a dragon, all the water in his body’s systems is replaced by fire.
 
Though, yes, we’d probably have seen dragons bleed fire in games and mythology before if that were true. lol

@Background Pony #B1D8  
An old comment, I know, but the hardest thing I recall him eating were sapphires in that cupcake given to him for his birthday. Sapphires are a blue variety of corundum, which has a compressive strength of 435,000 pounds per square inch (almost 23 times stronger than granite). However, it’s also possible that Spike’s saliva contains chemicals which soften minerals and thus make them easier to chew.

“Dumb lock, why do you have to remind me of melted cheese? You’re making me hungry.”

Dragon fire is magic.  
js

@Everyone:
 
We’re discussing the logic of how hot a cartoon dragon’s fire is and why it doesn’t seem to always be that hot. …We are such nerds.

@toxicitzi  
For the sake of knowledge, discussion is always fun. Can’t fathom what it’s like for politicians, though. XD

@Jim Prower  
well, let’s look at some things like NMM’s eternal night, there’s the eternal night intentions which draws things like that and the realism arguments for it. With this, visual information was a must have and if the animators didn’t think of it, well, here we are.
 
I’m not sure how best to explain this, but adding realism to anything feels on one part like covering up flaws, which is especially worse when there’s some fun fuck ups like this one here and there can also be not just lack of evidence, but contradictory evidence. For instance, I once had an argument over Twilight’s crown and why it wasn’t stupid to make the Element of Harmony into her everyday crown piece, a crown piece of such utmost power and balance importance that it was always left out in the open.. you can probably figure out just how fun that discussion was.  
I guess my point is that, it stops being fun when someone feels an urge to justify everything in the show without almost any reason at all other than because, or I have to defend the show, as though it’s unusual for entertainment to have any flaws.
 
it’s all subjective I suppose, I can see why some people would like adding realism and it’s not entirely pointless to add some things to the table that no one thought up, I can see how that’s fun when it’s for the sake of discussion.

Depends on how “accurate” to the “Story” you feel the animation is. You mentioned it yourself - the fire doesn’t really look any different because the animators didn’t bother to change anything. They technically didn’t have to. I mean…It’s a kid’s show, they don’t understand what we do as adults.
 
Ergo, I don’t mind using my imagination a bit and casting it as it’s written rather than how it’s drawn. I’m saying it’s possible and plausible rather than “IT SHOULD BE PORTRAYED JUST LIKE THIS.”

@Jim Prower  
here’s my answer.  
nope.
 
While these are some good examples you brought up, the only reason this would work is if his head was a literal blow torch, because you can clearly see that there isn’t as much flame as it is necessary to register this temperature to meet the melting point, besides the fact that these flames look no different from how they were in any of their previous appearances.
 

 
the only time they looked different was when the animators probably must have actually put some thought into the temperature of that flame.
 

 
Also, this comment kind of nullifies everything about all of this.  
@Ping_chan

@toxicitzi  
Main thing here to realize is that when you deal with concentrated flame (the sort you encounter with something like an oxyfuel torch) kept in a tight pattern, you can melt metal in seconds. That’s how things were welded before the advent of electric arc welders, considering welding is literally the joining of two pieces of metal by melting them together. In an arc-welding situation, this happens instantly. With a torch, you have to heat it up a bit, but - and I’ve done this myself - it’s possible to get a weld pool within a couple seconds
 
the use of a diffuse flame results in a much more spread out use of the fuel/oxidizer mixture, and results in a flame with similar energy but far lower “temperature”, though the flames themselves may not be any cooler, the energy is more spread out. We’ve used this technique at our machine shop to expand wear rings and such onto shafts - there’s no need to get those red-hot.
 
It’s entirely possible that Spike can control the concentration of his flame. Try changing the shape of your mouth while you blow out of it. I’m certain you can get a condition where you get a tight, concentrated air stream. Granted, it’s possible that the main flame doing the cutting is sheathed by an external, “dirty” flame, but I digress.
 
Also, the lock hasn’t completely melted, just the loop, which is typically 3/8” thick, and thinner material is much, much easier to heat.

@Jarkes  
Somepony already said that.

That’s 2800.4 degrees Fahrenheit.

@badassgrunt88  
That’s my headcanon, too.

@PonyPon  
I’ll give you that it’s not anywhere near as odd as the whole sun rotation mess, but I assure you that iron doesn’t melt in 2 or 3 seconds.
 
even wood has more of a fire resistance than that of the plastic aspect fire has given this iron padlock and I’m only saying this because wood is actually flammable, thus making it easier to burn. Even in the thickest flames, wood can hold up to whole minutes and even hours.
 
 
@crazybark  
I would have been more inclined to believe, it’s just a sign of growth..  
while he’s not concentrating how hot it is, he can’t also concentrate how cold it will be, so the same issue can happen regardless and it’s all because it’s one fucking thousand degrees CELSIUS..
 
I would even argue that the heat of his flame has to be more than that too, since the metal melted literally in just a few seconds.
 
the only answer you have at this point is this, “It’s just magic”.

to the comment on is accidental fire. his fire could be naturally warm but take concentration to make hot that would explain why the accidental fire didn’t colonel sander twilight

I guess you could say he’s bringing the heat.

@greaterlimits  
Because some things in their world are just too odd to bother speculating how to explain away.
 
Raising the sun is one of these things.
 
The speed at which this lock is melted isn’t.

@PwnyPony  
Why should I? I could just as easily make an argument that it is a metal that doesn’t even exist in our world.
 
I always find it strange when people try to apply real world logic to a world which is clearly not subject to the rules of our world.
 
Why do people have a problem with this yet no problem with the thousands of other things that don’t work with real world logic. Such as raising the sun. This is impossible as well and is in fact a far greater violation of real world rules.

@PwnyPony  
Also, you can’t pick Mercury. Cheater.