Can anybody tell me if it is worth 'priming' the model first, and if so, what aare the main benefits? Thanks!

Harry, yes it is worth priming it first, the advantages are that it shows up any surface marks that need correcting, and it helps the paint adhere better!

Vinnie

Thanks teacher! should i use a spray paint?

I think it's essential to prime with a spray, either rattle can or air spray. Priming it by brush ads too much thickness of paint.

Vinnie

priming is essential if you have used any putty to fill cracks. Priming fills in minor imperfections and give a smoother finish to your top coat

Perfect - thanks! Off to paint my first vehicle - Tamiya's Jeep!

I agree with Vinnie. Spraying the primer (generally) gives a nice even coat.

Just for the record, I use the Tamiya white primer in the rattle can...

I use either Halfords white or grey primer depending on what i am primming and what the finished paint scheme will be.

Tamiya spray primer is the best bar none. Only other hobby one with superfine pigments is the Floquil(via Testors) figure primers, but Tamiya's dry faster and sand better. Auto primer grain pigment is gigantic.

Krylon,OSH brand(DIY) is good.Auto primer for metals is OK,can be prissy with grainy or tacky surface.Nice German red oxide shades though.
cheers!