From: gorrie@hercules.cs.uregina.ca (Dennis Gorrie)
Subject: Painting bikes?
Originator: gorrie@hercules.cs.uregina.ca
Reply-To: gorrie@hercules.cs.uregina.ca (Dennis Gorrie)
Organization: University of Regina, Regina, Saskatchewan
Date: Sat, 7 Mar 1992 21:53:55 GMT


I don't have a lot of experience painting bikes but I have painted a few
cars.  I don't know why a chem tank would be needed to strip a bike frame,
and I suspect its more expensive and not easily available for most people.
I have used both chemical-gels and sand blasters which are cheap and easy
to find.  You do have to use a lot of care and its best to talk to someone
who has a lot of experience using this stuff before you try it yourself.
Also, I think hand-sanding with 220 grit automotive sandpaper should not
cause any damage to the frame, but you would want to finish it with
360 or 400 grit afterwards.   

Then you want to use a metal prep/etchant on the steel.  This prepares it
for the primer and also reduces rusting/oxidation if you have to leave
it over night. For primer, I prefer an green epoxy-base primer which adheres
better than most gray/red primer-surfacer paints.  You may then want to 
wet-sand, very gently, with 360/400 after the primer has dried.  This is 
just another step to smooth out imperfections, as well as give you an idea
as to how many primer coats you need.  I use 3 coats on a car.  On a bike
you would still have at least 2-3 thin coats I think.  

Then comes the paint.  You have to chose between acrylic enamel (slow drying,
more diffucult to sand/polish) or acrylic laquer (fast drying, easier to sand/
polish).  By no means should you ever consider using both types of paint on
the same surface unless it has been stripped of the previous paint. They
usually have an adverse reaction to each other that shows up as small cracks
in the paint after a few months to a year. 

You also have to choose the brand of paint.  Some like Centari will nickle
and dime you on the additives, like fish-eye remover, hardener, thiner, 
activator.  Others like Ditzler will provide all you need in the hardener and
thiner.  You take your chances if you mix/match products from two companies.

What colour of paint will you use?  Some are twice as expensive as others,
metalics are difficult to paint evenly for the first time, some tend to fade
and oxidize more rapidly (silver).   You can apply a few coats of clear-coat
to greatly improve the shine and depth of the finish, however, this kind
of paint-job is also more difficult to repair if you get a scratch.  
What about decals?  You might consider putting decals on last, so that
you can remove them, or you might put clear-coat over top to make them
permanent.  There are also a wide range of pin-stipes available (solid,
metalic, faded) that you can buy from places that do striping.  I don't have
the skills for hand-striping or air-brushing so I can't comment on that.

One last thing: a good paint gun.  Spray cans and spray bombs always tend to
drip and don't let you control the paint very well.  Paint guns let you
control the shape of the spray, the pressure, and the amount of paint, making
it easier for you to paint (if you have them set right that is).  

Anyways this info is regurgitated from what I have learned painting cars.
I would very much like to hear from people who paint bikes and what they
do to achieve a nice job.  Also, I have wanted to paint my C-Dale, but
I have no success at all in painting aluminum.  What kind of prep do you
do to aluminum to make paint adhere to it?  The primers I have used
don't do the trick.  I've done my 'tests' on Al lawn chairs.

Comments appreciated.  E-mail is just fine.


Article 54534 of rec.bicycles: