Any mask is better than nothing. A paintball one is full face right? All the better.
Not so true....to the best of my knowledge. I will admit I'm not fully aware of the strength of paint ball masks (I have played and worn them) but safety glasses are specificly designed to take high impact from solid objects. I've seen safety glasses stop a nail from a nail gun from penetrating more than a half inch. They guy was freaked out but his eye was safe....will paintball goggles stop something like that? Am asking, don't know...
anyways, check for a stamp of certification on them...in canada you'd want Class A (glasses) or B (goggles) CSA Z94.3.1-02 stamped on it somewhere. Not so familiar with American Standards but I think you'd be looking for an ANSI Z87.1 certification on the goggles, the American standards have 2 classifications i think, basic impact which the paintball goggles might meet...and high impact which i don't think they'll meet but you never know, would be great if they do. would be good to have the full face mask tho
Also, have you thought of a jigsaw for cutting out the window? If it's not an intricate cut the jibsaw might be better than the dremel if you have one handy, just make sure to get the right blade for steel, $5 at home depot. A bandsaw was mentioned....if you go that route just make sure you have a steel blade on the bandsaw and not wood...unless you're cutting the acrylic, then either is fine.
Lastly, yes you can cut acrylic with a dremel, slow the speed down on it and leave yourself a little room on the cut if you're trying to be precise as the acrylic will melt from the friction heat. just use a file or sandpaper to clean it up once cut.
[edit]BTW, i'm pretty sure the paint mask would be fine for just dremeling, I didn't make that clear, the above stuff i'd be more concerned about if you started on the bandsaw, circular saw, drill press, laithe and stuff like that, I just wanted to make sure pple didn't mistake the paintball goggles=safety glasses/goggles[/edit]