Which Sand paper grit to use for painting a motorcycle?

If you go to an AUTOMOTIVE PAINT STORE...
The staff there can better advise you on the
particular application you are attempting...

Very likely you are looking at ALUMINUM ...
(you might want to consider getting it powder coated or electroplated... Painting ALUMINUM is TOUGH).

There are "preparations" required to actually get
through the OXIDATION and allow YOUR
PRIMER PAINT (available in many colors) to stick
to the surface...

Then you can manipulate the surface with YOUR
"sand-paper"...

Anytime you sand through your PRIMER and expose the
ALUMINUM... You should repeat the process... PRIMER AGAIN
and only then apply your surface paint...

READING & understanding the directions on the paints you are using is CRITICAL to success... as is cleanliness ...

A good paint job is all about PREPARATION... but sanding
is quite drastic and should be done as part of the complete SYSTEM...

A tragic number of beginning painters think they can "spot sand" to feather the edges of a "chip"...

From a SURFACE (final finish) all that is accomplished by that is a deeper variation in the surface... that will now need to be leveled out (again).

Two ways to level:
- Primer- SURFACER (fine grit block sand)
- Sand it all down SMOOTH (and re-prime)

Sanding is a CRITICAL skill and can change the shape and LINES of your entire vehicle...

Read & heed the cautions on all paints & primers... Use dust masks, gloves, tac cloths, surface cleaners... eye protection and dust free + well ventilated areas (a lot harder than it sounds )...

With the proper sequencing... really beautiful finishes can be produced (WITHOUT all the gouges and dips caused by shabby sanding techniques)...

Hope this helps

Carnac the Magnificent

you did not provide info on the type of the paint and what surface it will be used on - there is difference between the floor, desk, wall and car body... all are flat surface but adhesion and work of the paint differs.

depending on the pre-existing paint, but you need always to "key-in" using 120 grit paper or 150 grit screen.

if paints are of same type, then paint in - if these are two different paints, you need to strip or isolate old paint, and then use new paint.

sand it down with some fin grit sand paper, apply a slight coat of rustolium, masking off the area with masking tape, so you dont create a larger area. Then ge touch up paint from your local dealer, some thinner and a refilable pray can, thin the touch up paint with the thinner in a 2 part paint to one part thinner ratio and spay a few coats on, should work.

Clean the old paint surface with TSP cleaner, then sand the surface lightly with ~400 grit wet or dry sandpaper (wet--dip in bucket of warm water often while sanding and sand carefully in any corners). Cut a 1/4-paper-length strip from a full sheet and fold twice into a 1/3-width square. Sand using just your fingers to hold the paper--no sanding block. Wash with clean hot water, and dry with a clean cloth (no paper towels). Mask off the area you don't want painted, then using an epoxy-type paint spray can, spray the area evenly and lightly for the first coat. Follow can directions for the second coat. Remove the masking tape and paper shortly after the second coat--peel the paper and tape AWAY from the new paint at all points and don't let any of it get stuck in the new paint before it drys. If the second coat was applied fully wet overall without running, it should turn out very well. Good luck!

Initial sanding can be done with 100 or it will take you a year to sand it down. You can either use a power sprayer and have paint mixed to match, or use cans made by duplicolor ...You will never match the existing paint though because it changes with age...I use the larger cans when available (marked for "vans") You can use 400 wet paper between coats and if you want to get crazy, use 800 wet when finished. Wait a few weeks and use white compound, clean well, in another couple of weeks, use clear-coat, sand again and when fully cured (few more weeks) then wax. Never sand unless paint has dried for at least 24 hours...even when it looks and feels dry, it can roll, and damage everything you have done.

Your going to have to sand prime sand prime sand paint. Just increase the grit number each time, there has to be some adhesion

First Wash the area, than take a dremel and with the wire wheel @ high speed, grind off the bistering and feather as best into good paint. Next rough up the area with some 100 grit sand paper. Use body filler (bondo 2 part filler) and smooth over with plastic blade. When dried work with 220 grit sand paper till you achieve the lines you want. spray cover with primer and apply touch up paint(Dealer has the best matchs) in coats. When happy with color use a 400 grit wet sandpaper to get a highly smooth finish and when dried cover with a clear coat finish.(Auto part stores). Buff when that dries and I guarantee thats the cheapest easiest d-i-y- fix you can get.