I've done a few frames with rattle cans and can offer some solid advice. First, if the original paint is not too bad, leave it on and rub it down with 320 grade wet and dry (used wet). This gives a key for the new paint to adhere to. Fill any scratches and pits.
Next give it at least two coats of primer/filler, preferably white because grey or any other colour will adversely affect the shade of the top coats. Only use grey primer if the end finish is black or a very dark colour. You'll use at least one whole can for frame and forks. Spray only in a warm environment. It also helps if the frame itself is warmed up slightly using a hairdryer.
When the primer is dry, if you've done a good job you can just rub down very gently with 400 grade to de-nib the surface. If there are any runs you'll need to sand these smooth. Leave the frame for a few days before applying the next coat.
Give the frame and forks one coat of gloss, then as soon as it's dry (within anhour, usually) give it another coat. The trick is to apply sufficient paint to give a nice gloss but not so much that it creates runs. I would expect to use one can for this but sometimes you need more, so buy two cans just in case.
Allow at least a day for this to dry. I would apply a coat or two of lacquer to give it that pro look. One can should be enough for this.
So, buy two cans of primer, two of colour, and one of lacquer.
I've done a few frames with rattle cans and can offer some solid advice. First, if the original paint is not too bad, leave it on and rub it down with 320 grade wet and dry (used wet). This gives a key for the new paint to adhere to. Fill any scratches and pits.
Next give it at least two coats of primer/filler, preferably white because grey or any other colour will adversely affect the shade of the top coats. Only use grey primer if the end finish is black or a very dark colour. You'll use at least one whole can for frame and forks. Spray only in a warm environment. It also helps if the frame itself is warmed up slightly using a hairdryer.
When the primer is dry, if you've done a good job you can just rub down very gently with 400 grade to de-nib the surface. If there are any runs you'll need to sand these smooth. Leave the frame for a few days before applying the next coat.
Give the frame and forks one coat of gloss, then as soon as it's dry (within anhour, usually) give it another coat. The trick is to apply sufficient paint to give a nice gloss but not so much that it creates runs. I would expect to use one can for this but sometimes you need more, so buy two cans just in case.
Allow at least a day for this to dry. I would apply a coat or two of lacquer to give it that pro look. One can should be enough for this.
So, buy two cans of primer, two of colour, and one of lacquer.
Here's one I did earlier:
http://www.classiclightweights.co.uk/bikes/cb-jubilee-rb.html
And here's another of mine:
http://www.classiclightweights.co.uk/bikes/ernie-clements-rb.html
Hope this helps - and good luck!