plastic sanding question

[him]

Im currently trying to get my machine back on the road and have a quick question. What grit of sand paper do i use to sand the plastic. I've read to use a 220 but that seems a little to rough...Any advice

 

[paulos]

wish i could help you m8 but i cant,i will keep track of this tho coz im gonna av to do the same on me mirrors and inners::

 

[manatrader]

What part of the plastic are you trying to sand? I used 220 on the edges after I put the frame sliders on no problems, very smooth. If you want something more fine, you can use 400 metal sandpaper, after that you will have to go to a wet sand paper used in painting and body work.

 

[NearDeath]

I am thinking you would want to have it sand blasted or something to get the paint off first and then sand till smooth, and paint...

 

[him]

Im redoing the entire bike only part i wont be doing is the tank. Im trying to save a little cash by doing the sanding myself or at least getting started on it.

 

[Wag]

Whatever you do, don't sandblast plastic! Very quickly, you won't have any paint OR plastic!

There are some really fine grit sandpapers out there. Go to a body shop and see what they have. I've seen 800 and, I think, 1,200 grit sandpaper. After that, you paint and use the wet-dry to color sand before putting on the first clear coat. Then in between each clear coat. I'd start with 400 grit and move up from there.

--Wag--

 

[him]

Im tryin to remove the factory coat. Right now i have 1500 grit so ill be fine then thanks

 

[Ludicrous Speed]

Unless the plastic is terribly rashed, or the paint is peeling leave the factory paint on it!  That is probably the best bond you will get.  

I would use a light grey scotchbrite pad to scuff it all up (WET), then prime it.  If you plan on painting directly over the factory paint (no primer), use 600 grit wet.

You are just making too much work (and mess) stripping it down bare.

 

[him]

So i can wet sand it with 600 grit then just apply a prime over teh factory paint!? WIll this work even if im going for a different color

 

[Ludicrous Speed]

So i can wet sand it with 600 grit then just apply a prime over teh factory paint!?  WIll this work even if im going for a different color

That is what primer is for. To give build (fill small imperfections), give an even color (so translucent paints don't look splotchy) and to give the new paint something stable to adhere to.

I would highly suggest using a polyurethane primer. These have a catalyst, and do not tend to shrink or give sand scratch swelling.

 

[him]

no one more question...i have some cracks and i was planning on melting platic in them to fill em up...should i do this before or after i sand it down

 

[Ludicrous Speed]

You want to sand the affected area down to the plastic, do your repair, then you will probably have to use a filler of some sort to level it off. Use increasingly finer grits until you are to about 400 in the area you repaired. Then sand/scuff the rest before priming.