Paint my gas tank

I have noticed a number scratches in the paint on my gas tank also a little welding which was not smoothed over before painting. I have seen a lot about painting on this site (I have never tried it yet) so my question what are the grades of sand paper to use and in what order? Would stripping by chemical stripper be good? or just a good sanding/bondo job be enough?
looking forward to some input (n maybe pics?)

 

the smaller the number on the sand paper the more course it is

80 grit is rougher than 1000 grit which is more rough than 2500 grit.
you don't have to start with 80 it depends on how the surface is and what needs to be done. I would start with 300 maybe 400 grit the more the part take shape the more you should move up to 600-800 grit and for a very fine/ smooth finish use 1000-1500. grit some people don't stop there they take it to the very finest grit.

just don't over do it .

 

Don't use any grade of SAND PAPER on your paintwork, use wet & dry.
No need to strip all paint off, if you only have a few scratches or marks.
Nib it all down with 280 W&D, coat it all with primer / filler, then fill the blemishes with fine surface auto filler, nib down when dry & hard with 380, or finer, then top coat.

 

If you're not going to grind down the weld.
You may be able to get the scratches out with Rubbung compoud.
Rubbing compoud is about equal to 2000 grit sandpaper.
My tank shined but it loooked like the clear coat had frost in it.
A lot of rubbing and most of the "frost" is gone.
This spring I will take the buffer to it.

 

Thanks guys! As usual good advice. (Maybe I'll do video?)

 

When all else fails wet sand, primer the tank 2 coats, do a final wet sand with 1500 grit wet or dry paper (use wet), then spray 2-3 coats of Krylon Glossy Black. Let er dry for 3-4 days. You can use fine rubbing compound to complete but only if it really needs it.