Have bought an internal panel door which has some glass in it.  Basically its really heavy and made from solid pine.  

I have some gloss paint .... what should I put underneath before I paint it .. ie undercoat.  Its only an internal door, so does not need to be weatherproof.  Also, it says it has to have three coats of paint before it should be hung?  Is this really necessary?  Can I not hang it first and then paint it?  

Tips etc. please, thanks!!!

hmm

ive painted a lot of doors at home... i would definately paint it before you hang it, its incredibly awkward to cover all of the door when its hung

if possible, do it outside when theres some nice weather

you want an undercoat (white, weatherproofed undercoat usually comes in grey - but you said you dont need that)

do two undercoats, then gloss it...

i would allow 48 hours between each coat, or at minimum 24 hours, to give it time to really dry out

i wouldnt gloss it outside, youll get all sorts sticking to it.

also have a look into satin wood paint, I think it looks better than gloss.

yea youre actually right about the gloss my bad...
hang it then gloss

Make sure you keep the dog/cat away too, unless you want them painted. Definitely give it an undercoat, usually one is enough although if it sinks in quickly then give it a second. Then two thin layers of paint. Lying the door down means you arent going to have a problem with runs but this is personal preference and shouldnt happen providing you dont put too much on at once.

get some of that green nylon scouring stuff that is normally used to clean pans too. Its non scratch but you can use it to sand down between coats rather than use sandpaper. Same stuff as the rough side on the dual action sponge scourers.

Advantage is it doesnt wear off the paint or damage the surface if you press too hard. It just takes the lifted wood fibres away.