I decided to strip the black finish of my cheap strat copy with a heatgun and scaper but I'm having some trouble. I read that this was the best method but I'm having problems with it.

I can get the glossy paint layer off very easily, but a fairly thick matte grey kind of layer is left behind which is really hard to get off, in fact when I do manage to get it off, it often takes some of the wood underneath with it. What I am doing wrong? Am I not heating up the finish enough?
There are basically three ways of stripping a guitar:
Heat gun & scraper
Chemical stripper
Sanding (mechanical and/or by hand)

They all have their pros and cons.
I've never tried a heat gun, so I can't help you, but I'd be worried about heat damage.
I did try chemical stripper (Nitromors) and it did nothing.
A mechanical sander can be a little aggressive and almost certainly won't get into all the nooks and crannies.
So, the only way I've ever fully stripped a guitar (1st project) was sanding by hand and it takes a looooong time. But I figure it's the most controllable method and should give the best results.
I thought about trying nitromors but figured it wouldn't be strong enough. I might try and power sand the front, back and sides but I guess I will need to hand sand the inside of the horns. I'm pretty annoyed that the heat gun hasn't worked as from what I've heard, it makes stripping a body pretty easy, maybe I need to hold the gun further away. I'm more inclined to hand sand when I can be bothered as since using the heat gun I have developed a sore throat, which is kind of worrying, the fumes stink.
Yeah I thought that might be the case, I won't do any more stripping without a respirator.