You often hear the words "aircraft grade alluminum" when looking at pit bike parts. Aside from the fact that alluminimum comes in hundreds of different grades each one for a specific purpose and all of them are suitabe for use somewhere on a plane your "aircraft grade alloy" is just what ever the engineers decided to use.
.I couldnt care less. But I find it funny that you asked how to get the paint off over 10 days ago and have wasted 2 weekends (and in your case probably your school holidays) trying to track down something that you can get at your local shops and you could have your little project done by now.
Im not young enough to know everything anymore so you should keep looking for "aircraft paint stripper" and ignore the advice of a tradesman who used paint stripper just about every day