Posted 30 January 2012 - 10:21 AM
Bigger is certainly better when it comes to the tank on a compressor, but if you're prepared to be patient and only want a reasonably good finish as opposed to pro body shop perfection (and to be honest if you're a novice spraying in a garage,then your'e not going to get pro results anyway), then you can get away with a cheap compressor with a smaller tank.
I actually sprayed mine a panel at a time using just a tiny hobby compressor that had just a six litre tank designed for running a nail gun. Whilst I wouldn't particularly recommend this, as you can only pass over each panel a hand full of times before having to stop and wait for the tank to refill and build the pressure back up. With a fair bit of flatting back afterwards, then it is possible to spray a small car like a mini this way a panel at a time and get reasonable results (certainly far better results than you would ever get with rattle cans any way). The cheap 75 litre hobby compressors that you can pick up from Aldi & Lidl from time to time would therefore be sufficient for this, although not as ideal as a bigger tanked unit would be. If you do go for one of these, then make sure you are standing outside the store at opening time the day they go on sale, otherwise you probably wont get one as they tend to sell out rather fast (or at least they do around here any way!!)
A good compromise is just to buy your own spray gun though and then simply hire a decent compressor with a large tank for the couple of days that you will be spraying. This is a much cheaper option and also means that you don't end up paying out for a huge compressor that will take up loads of room and you will probably never get much use out of again anyway.
The amount of paint you use will depend on your experience, a pro will use much less as they will loose much less in over spray than a novice will. I used 5 litres of celly white diamond + 5 litres of thinners to spray my mine (not including the roof) an excessive amount by a lot of peoples standards, but with my level of skill I needed that amount to get decent coverage.