Painting over chrome forks without sanding chrome finish

[ddog]

My forks have a sizable skint place that reveals shiney chrome under
it.

I haven't cracked into this sites painting article yet, but all
painting articles I've seen so far never say anything about removing
paint and painting over chrome forks. Generally, all I've seen say
sand, etc... and if the manufacturer could paint it without roughing up
the chrome finish, is there a way do-it-yourselfers can too?

For a real nice powder coat job, my main reservation also would be bead
blasting the chrome to paint over it. Maybe that's why most quit making
chrome forks, especially the custom frame builders. So the choices for
wet or powder paint, are sand or bead blast. Is there no way to paint
over chrome forks, front and rear, without defacing chrome surface
underneath? And what did Raleigh use to paint them, low heat infared
curing ovens? Maybe that's why they skint off so easy - ??? Chromed
forks could possibly be a flawed process of paint adhesion and
maintaining chrome integrity simultaneously.


Thanks!

 

[jim beam]

ddog wrote:
> My forks have a sizable skint place that reveals shiney chrome under
> it.
>
> I haven't cracked into this sites painting article yet, but all
> painting articles I've seen so far never say anything about removing
> paint and painting over chrome forks. Generally, all I've seen say
> sand, etc... and if the manufacturer could paint it without roughing up
> the chrome finish, is there a way do-it-yourselfers can too?
>
> For a real nice powder coat job, my main reservation also would be bead
> blasting the chrome to paint over it. Maybe that's why most quit making
> chrome forks, especially the custom frame builders. So the choices for
> wet or powder paint, are sand or bead blast. Is there no way to paint
> over chrome forks, front and rear, without defacing chrome surface
> underneath? And what did Raleigh use to paint them, low heat infared
> curing ovens? Maybe that's why they skint off so easy - ??? Chromed
> forks could possibly be a flawed process of paint adhesion and
> maintaining chrome integrity simultaneously.
>
>
> Thanks!
>
you can paint over chrome, as you can see, but it's not generally
regarded as ideal. anyway, the best paint removal option is chemical -
plenty of choices at your local hardware store. leave the chrome alone
- make sure it's free of oil and dirt before repainting/refinishing.

 

[Grolch]

Painting chrome can be done without defacing the polished surface. Car
makers do it all the time with trim items and such, (i.e. Painting chromed
strips black around windows). You have to acknowledge that adhesion will not
be the same as for a surface that has been roughened or de-glossed. Impact
resistance of the coating will be impaired and manifest as easily chipped
coating. Ensuring the parts are "super-clean" is critical. There are primers
available formulated for adhesion to such surfaces... Thin film epoxy
primers come to mind. There are probably others. The sanding or roughening
of a surface is the best way to ensure adhesion as the act of blasting or
sanding increases the surface area to provide an anchor-pattern or "tooth".

Grolsch


"ddog" <[email protected]> wrote in message
news:[email protected]...
> My forks have a sizable skint place that reveals shiney chrome under
> it.
>
> I haven't cracked into this sites painting article yet, but all
> painting articles I've seen so far never say anything about removing
> paint and painting over chrome forks. Generally, all I've seen say
> sand, etc... and if the manufacturer could paint it without roughing up
> the chrome finish, is there a way do-it-yourselfers can too?
>
> For a real nice powder coat job, my main reservation also would be bead
> blasting the chrome to paint over it. Maybe that's why most quit making
> chrome forks, especially the custom frame builders. So the choices for
> wet or powder paint, are sand or bead blast. Is there no way to paint
> over chrome forks, front and rear, without defacing chrome surface
> underneath? And what did Raleigh use to paint them, low heat infared
> curing ovens? Maybe that's why they skint off so easy - ??? Chromed
> forks could possibly be a flawed process of paint adhesion and
> maintaining chrome integrity simultaneously.
>
>
> Thanks!
>

 

[Nigel Cliffe]

ddog wrote:
> My forks have a sizable skint place that reveals shiney chrome under
> it.
>
> I haven't cracked into this sites painting article yet, but all
> painting articles I've seen so far never say anything about removing
> paint and painting over chrome forks. Generally, all I've seen say
> sand, etc... and if the manufacturer could paint it without roughing
> up the chrome finish, is there a way do-it-yourselfers can too?

Non scientific, practical experience.

I have painted a chromed alloy stem; Firstly, thoroughly degrease and clean
with thinners, dry. Then coating in a etch primer(*), applied with an
airbrush, allowing to dry and then etch away for a couple of weeks (keep
covered to keep dust out, but allow some air flow at same time). Then
painted semi matt black using acrylic black(**). The paint was two or three
coats, with a short time to dry between each coat.

The results are reasonably robust and have lasted at least four years. It
has flaked a tiny bit here and there. The comparison with a chrome part
which has not been etch primed is huge; the paint just peels off the
unprimed item almost as you touch it.

Not sure how well a fork would handle the paint; I might be tempted to use a
paint which had some flexibility built into it, such as those designed for
coating plastic car bumpers (fenders in US ?). I'd still prime the chrome
surface first.


* single part type, from Phoenix Precision Paints in the UK, because I had
some in the workshop
** spray can, think its intended as a primer and a base colour, from
Halfords, a UK car accessory shop, also a can that happened to be in the
workshop.



- Nigel


--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

 

[David L. Johnson]

On Tue, 09 Jan 2007 19:40:27 +0000, Nigel Cliffe wrote:

>> I haven't cracked into this sites painting article yet, but all
>> painting articles I've seen so far never say anything about removing
>> paint and painting over chrome forks. Generally, all I've seen say
>> sand, etc... and if the manufacturer could paint it without roughing
>> up the chrome finish, is there a way do-it-yourselfers can too?
>
> Non scientific, practical experience.
>
> I have painted a chromed alloy stem; Firstly, thoroughly degrease and clean
> with thinners, dry. Then coating in a etch primer(*), applied with an
> airbrush, allowing to dry and then etch away for a couple of weeks (keep
> covered to keep dust out, but allow some air flow at same time). Then
> painted semi matt black using acrylic black(**). The paint was two or three
> coats, with a short time to dry between each coat.
>
> The results are reasonably robust and have lasted at least four years. It
> has flaked a tiny bit here and there. The comparison with a chrome part
> which has not been etch primed is huge; the paint just peels off the
> unprimed item almost as you touch it.

I guess I am missing something. For one thing, it was standard practice
in the '60s for Italian framemakers to first chrome plate the frame, then
paint over it. My '69 Frejus was partially chrome plate under the paint
(the headtube was totally chrome, but they only left the lugs unpainted,
and they chromed most of the stays but painted over half of the length).
Others were completely chromed and then painted over.

How did their paint stick, but it won't now?

On the other hand, if it's chrome plated, why not leave it exposed?

--

David L. Johnson

__o | A mathematician is a machine for turning coffee into theorems.
_`\(,_ | -- Paul Erdos
(_)/ (_) |

 

[* * Chas]

"David L. Johnson" <[email protected]> wrote in message
news:[email protected]...
> On Tue, 09 Jan 2007 19:40:27 +0000, Nigel Cliffe wrote:
>
> >> I haven't cracked into this sites painting article yet, but all
> >> painting articles I've seen so far never say anything about removing
> >> paint and painting over chrome forks. Generally, all I've seen say
> >> sand, etc... and if the manufacturer could paint it without roughing
> >> up the chrome finish, is there a way do-it-yourselfers can too?
> >
> > Non scientific, practical experience.
> >
> > I have painted a chromed alloy stem; Firstly, thoroughly degrease and
clean
> > with thinners, dry. Then coating in a etch primer(*), applied with an
> > airbrush, allowing to dry and then etch away for a couple of weeks
(keep
> > covered to keep dust out, but allow some air flow at same time). Then
> > painted semi matt black using acrylic black(**). The paint was two or
three
> > coats, with a short time to dry between each coat.
> >
> > The results are reasonably robust and have lasted at least four years.
It
> > has flaked a tiny bit here and there. The comparison with a chrome
part
> > which has not been etch primed is huge; the paint just peels off the
> > unprimed item almost as you touch it.
>
> I guess I am missing something. For one thing, it was standard practice
> in the '60s for Italian framemakers to first chrome plate the frame,
then
> paint over it. My '69 Frejus was partially chrome plate under the paint
> (the headtube was totally chrome, but they only left the lugs unpainted,
> and they chromed most of the stays but painted over half of the length).
> Others were completely chromed and then painted over.
>
> How did their paint stick, but it won't now?
>
> On the other hand, if it's chrome plated, why not leave it exposed?
>
> --
>
> David L. Johnson

They probably used a good primer on your frame. We sold Frejus and Legnano
bikes and they always had very good paint jobs for the price range as
compared to say Botteccia bikes. The paint didn't chip very easily.

I've seen a lot of European frames from the mid '70s up through the '90s
that don't appear to have ever had any primer applied. The finish coat was
painted on to the bare metal.

How can I tell? When the paint chips, there is no sign of primer on the
frame or back side of the paint chips.

Worse, it seems that many builders didn't make much of an effort to clean
off the brazing flux before painting either. Corrosion forms under the
paint near the brazed areas.

Italian bikes seem to be the worst offenders, Colnago for example.

Chas.

 

[sergio]

* * Chas wrote:
> They probably used a good primer on your frame.

Yes, indeed.
The needed primer is simply not available in small supplies (e.g. by
Dupont).

> Italian bikes seem to be the worst offenders, Colnago for example.

Might have been true, but not really so nowadays.
I can assure that the official Colnago painter, just outside this town,
knows how to do the job properly.

Sergio
Pisa

 

[* * Chas]

"sergio" <[email protected]> wrote in message
news:[email protected]...
>
> * * Chas wrote:
> > They probably used a good primer on your frame.
>
> Yes, indeed.
> The needed primer is simply not available in small supplies (e.g. by
> Dupont).
>
> > Italian bikes seem to be the worst offenders, Colnago for example.
>
> Might have been true, but not really so nowadays.
> I can assure that the official Colnago painter, just outside this town,
> knows how to do the job properly.
>
> Sergio
> Pisa
>

That's good to know.

I have a 1987 Colnago mountain bike and the paint peeled off one side of
the fork and crown. The metal underneath was never prepped for painting.

Chas.

 

[Werehatrack]

On 9 Jan 2007 06:05:30 -0800, "ddog" <[email protected]> may
have said:

>My forks have a sizable skint place that reveals shiney chrome under
>it.
>
>I haven't cracked into this sites painting article yet, but all
>painting articles I've seen so far never say anything about removing
>paint and painting over chrome forks. Generally, all I've seen say
>sand, etc... and if the manufacturer could paint it without roughing up
>the chrome finish, is there a way do-it-yourselfers can too?
>
>For a real nice powder coat job, my main reservation also would be bead
>blasting the chrome to paint over it. Maybe that's why most quit making
>chrome forks, especially the custom frame builders. So the choices for
>wet or powder paint, are sand or bead blast. Is there no way to paint
>over chrome forks, front and rear, without defacing chrome surface
>underneath? And what did Raleigh use to paint them, low heat infared
>curing ovens? Maybe that's why they skint off so easy - ??? Chromed
>forks could possibly be a flawed process of paint adhesion and
>maintaining chrome integrity simultaneously.

Although paint adhesion to chrome is not as strong as with bare steel,
in my experience it's usually better to accept the shortcomings of
undamaged chrome under the paint than to try to remove or roughen it.
If the chrome is bead-blasted, it's likely to flake and lift, leaving
a surface that is next to impossible to finish well. If it's sanded,
the paint will tend to fisheye in places, particularly if the nickel
underlay is exposed by the sanding.

IMO, your best bet is to simply clean it conventionally, apply a
suitable primer if the paint is not fully opaque, and then paint
normally.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

 

[Donald Gillies]

"David L. Johnson" <[email protected]> writes:

>How did their paint stick, but it won't now?

>On the other hand, if it's chrome plated, why not leave it exposed?

1. It is one thing to chrome a frame. It is quite another thing (and
quite an expensive thing) to POLISH a frame COMPLETELY so that the
chrome will have a mirror reflection everywhere.

People don't realize this and sometimes strip all the paint off of
a chromed frame, only to see that the paint was covering up
something worth hiding in the un-exposed areas ...

2. What is most often done is that a frame is polished in some areas
(head lugs, fork tips, seat stays and chain stays), and the main
triangle and other areas are coated with a clear lacquer-type of
paint. If done well, the finish can be spectacular, as in the
classic wilier triestina frameset of the 1970's, or the rampar
superbe of 1979 :

http://search.bikelist.org/getmsg.asp?Filename=classicrendezvous.10612.1200.eml

In order to achieve a finish that lasts for more than a few
months, you need special preparation of the area to be painted.
One way to do proper preparation is described here :

http://search.bikelist.org/getmsg.asp?Filename=classicrendezvous.10612.1200.eml

It's a product called "Glisten" ( http://www.por15.com/ )
available in australia. Similar products are probably available
in the USA.

- Don Gillies
San Diego, CA

 

[Donald Gillies]

"David L. Johnson" <[email protected]> writes:

>How did their paint stick, but it won't now?

>On the other hand, if it's chrome plated, why not leave it exposed?

1. It is one thing to chrome a frame. It is quite another thing (and
quite an expensive thing) to POLISH a frame COMPLETELY so that the
chrome will have a mirror reflection everywhere.

People don't realize this and sometimes strip all the paint off of
a chromed frame, only to see that the paint was covering up
something worth hiding in the un-exposed areas ...

2. What is most often done is that a frame is polished in some areas
(head lugs, fork tips, seat stays and chain stays), and the main
triangle and other areas are coated with a clear lacquer-type of
paint. If done well, the finish can be spectacular, as in the
classic wilier triestina frameset of the 1970's, or the rampar
superbe of 1979 :

http://www.bulgier.net/pics/bike/Catalogs/Raleigh79/01_pro_superbe.jpg

In order to achieve a finish that lasts for more than a few
months, you need special preparation of the area to be painted.
One way to do proper preparation is described here :

http://search.bikelist.org/getmsg.asp?Filename=classicrendezvous.10612.1200.eml

It's a product called "Glisten" ( http://www.por15.com/ )
available in australia. Similar products are probably available
in the USA.

- Don Gillies
San Diego, CA

 

[Marcus Coles]

Donald Gillies wrote:
> "David L. Johnson" <[email protected]> writes:
>
>> How did their paint stick, but it won't now?
>
>> On the other hand, if it's chrome plated, why not leave it exposed?
>
> 1. It is one thing to chrome a frame. It is quite another thing (and
> quite an expensive thing) to POLISH a frame COMPLETELY so that the
> chrome will have a mirror reflection everywhere.
>
> People don't realize this and sometimes strip all the paint off of
> a chromed frame, only to see that the paint was covering up
> something worth hiding in the un-exposed areas ...
>
> 2. What is most often done is that a frame is polished in some areas
> (head lugs, fork tips, seat stays and chain stays), and the main
> triangle and other areas are coated with a clear lacquer-type of
> paint. If done well, the finish can be spectacular, as in the
> classic wilier triestina frameset of the 1970's, or the rampar
> superbe of 1979 :
>
> http://www.bulgier.net/pics/bike/Catalogs/Raleigh79/01_pro_superbe.jpg
>
> In order to achieve a finish that lasts for more than a few
> months, you need special preparation of the area to be painted.
> One way to do proper preparation is described here :
>
> http://search.bikelist.org/getmsg.asp?Filename=classicrendezvous.10612.1200.eml
>
> It's a product called "Glisten" ( http://www.por15.com/ )
> available in australia. Similar products are probably available
> in the USA.
>
> - Don Gillies
> San Diego, CA

Here http://www.stoprust.net/
Color Chrome is the transparent colored material.

I saw a bike refinished at home with similar stuff.

The owner said the trick was spraying an even coat of the color layer to
avoid shading. I don't know how much natural talent, equipment or
spraying experience the guy had, but with new decals it looked factory
fresh.

Marcus