Does painting clear over old bikes protect from rust well enough?



D

ddog

Guest
Clear paint has the least base paint seal protection, but is this a
feasible short term option while getting all systems upgraded before
considering a nice powder coat paint job? I just have some cable wire
worn spots and some chips here and there mostly.


Thanks!!
 
ddog wrote:
> Clear paint has the least base paint seal protection, but is this a
> feasible short term option while getting all systems upgraded before
> considering a nice powder coat paint job? I just have some cable wire
> worn spots and some chips here and there mostly.



yes. nail polish works wonders.
 
On Feb 6, 2:48 pm, jim beam <[email protected]> wrote:
> ddog wrote:
> > Clear paint has the least base paint seal protection, but is this a
> > feasible short term option while getting all systems upgraded before
> > considering a nice powder coat paint job? I just have some cable wire
> > worn spots and some chips here and there mostly.

>
> yes. nail polish works wonders.


Thanks Jim, I appreciate the information!
 
In article <[email protected]>,
jim beam <[email protected]> wrote:

> ddog wrote:
> > Clear paint has the least base paint seal protection, but is this a
> > feasible short term option while getting all systems upgraded before
> > considering a nice powder coat paint job? I just have some cable wire
> > worn spots and some chips here and there mostly.

>
>
> yes. nail polish works wonders.


That was my thought too, if you're just covering up dings for the short
term. It's cheap, it's got its own paintbrush, and if you're married or
have a girlfriend you probably don't even have to buy it.

Although in the past 40 years of riding bikes I've never seen a paint
chip rust through. I have heard from several people that clearcoat over
bare steel is not a good long-term plan as the clearcoat just doesn't
seal well enough against moisture. I've never tried it myself, so for
all I know this could be jive.

Although Bob Brown did do some kind of copper plating of a frame with a
brush-on or spray on solution. I don't know how well it would hold up,
but the end result looks pretty neat. I think the coating ends up being
about one molecule thick, though.

http://www.bobbrowncycles.com/images/gallery/frame_cu1.jpg

http://www.bobbrowncycles.com/images/gallery/frog_cu4.jpg

http://www.bobbrowncycles.com/images/gallery/assem_do7.jpg

http://www.bobbrowncycles.com/images/gallery/head_cu2.jpg
 
On Feb 6, 6:24 pm, Tim McNamara <[email protected]> wrote:

> Although in the past 40 years of riding bikes I've never seen a paint
> chip rust through. I have heard from several people that clearcoat over
> bare steel is not a good long-term plan as the clearcoat just doesn't
> seal well enough against moisture. I've never tried it myself, so for
> all I know this could be jive.



Tim,

I realize for bare metal that clear would not be enough by itself. The
only place like that to worry about is rust proofing my seat post
clamp and repainting a close Walmart metallic green. And I have a big
place where shifter cable vibrated or rubbed down to the porous
primer. So will try clear on it first, and if primer surface absorbs
it, then will paint a circular section on down tube with the Walmart
green (Raleigh racing stripe). Other than that its just little chips.
But the clear should really may the Raleigh dark metallic green stand
up. It looks fine 10 feet away now, if you wear bifocals :)

The only thing about clear is it will come off easier than a white or
red opaque enamel paint and you won't see it peel. So it will just
take inspections and recoating with Walmart clear. Bob Brown's paint
jobs, no matter how thin, look great, but they also look like it may
cost a little more than a few Walmart spray cans, ha-ha. The worst
thing about powder coating is the lag time without a bike, if its your
only one :-(

I just bought my IRD 5 speed freewheel, frame saver, SRAM PC-89R
chain, and 9 speed pulleys for my Centaur rd so will be touching bike
up in next couple of weeks; before my LBS mechanic, who converted my
Ultegra octagon BB/Dura Ace crank, will hook up and adjust all my
Suntour Power Swift Shift and assemble rear end. Every nut and bolt
was a project within itself, so want to seal the paint so I can just
ride for now. A front rack, fenders, 3W light, and Phil Wood Hub
wheels (much) later, and I'll be done for the most part except bar/
stem adjustments, hopefully.


Thanks!
 
On Feb 6, 5:24 pm, Tim McNamara <[email protected]> wrote:
> In article <[email protected]>,
> jim beam <[email protected]> wrote:
>
> > ddog wrote:
> > > Clear paint has the least base paint seal protection, but is this a
> > > feasible short term option while getting all systems upgraded before
> > > considering a nice powder coat paint job? I just have some cable wire
> > > worn spots and some chips here and there mostly.

>
> > yes. nail polish works wonders.

>
> That was my thought too, if you're just covering up dings for the short
> term. It's cheap, it's got its own paintbrush, and if you're married or
> have a girlfriend you probably don't even have to buy it.
>
> Although in the past 40 years of riding bikes I've never seen a paint
> chip rust through. I have heard from several people that clearcoat over
> bare steel is not a good long-term plan as the clearcoat just doesn't
> seal well enough against moisture. I've never tried it myself, so for
> all I know this could be jive.



In the 1980s, a friend bought a Gios frame that was used at bike
shows. It was clearcoated, but otherwise unpainted; the intent was to
show off the workmanship of the frame. Long story short: although he
never rode that frame in the wet, and always stored in his apartment,
within 2 years, it was covered in patchy surface rust and he was
forced to have it painted.
 
Clear coat will protect the surface from any corrosion provided there is
enough DFT (Dry Film Thickness). The clear coat protects the surface on a
strictly barrier mechanism. That is to say, if you apply in the range of 3
to 6 mils (75 -150microns) the frame will be well protected. I would use a
urethane based clearcoat. The only reason that pigmented coating appear to
protect better is that they give avisula clue as to eveness of coverage and
thickness (opacity) thereby giving some assurance of adequate DFT. If using
spray cans I would suggest in the order of 4 to 6 coats MINIMUM.

HJ Wilke, NACE (National Association Of Corrosion Engineers)



"ddog" <[email protected]> wrote in message
news:[email protected]...
> Clear paint has the least base paint seal protection, but is this a
> feasible short term option while getting all systems upgraded before
> considering a nice powder coat paint job? I just have some cable wire
> worn spots and some chips here and there mostly.
>
>
> Thanks!!
>
 
"Grolch" <[email protected]> writes:

>The only reason that pigmented coating appear to protect better is
>that they give avisula clue as to eveness of coverage and thickness
>(opacity) thereby giving some assurance of adequate DFT. If using
>spray cans I would suggest in the order of 4 to 6 coats MINIMUM.


Maybe we need a new type of clearcoat - like Reynolds 953 tubing -
that you apply (and is opaque), but after you bake the coating it
turns clear ?? That would be a hoot, and it would certainly solve the
problem you are describing ...

- Don Gillies
San Diego, CA
 
On Feb 6, 10:53 pm, "Grolch" <[email protected]> wrote:
> Clear coat will protect the surface from any corrosion provided there is
> enough DFT (Dry Film Thickness). The clear coat protects the surface on a
> strictly barrier mechanism. That is to say, if you apply in the range of 3
> to 6 mils (75 -150microns) the frame will be well protected. I would use a
> urethane based clearcoat. The only reason that pigmented coating appear to
> protect better is that they give avisula clue as to eveness of coverage and
> thickness (opacity) thereby giving some assurance of adequate DFT. If using
> spray cans I would suggest in the order of 4 to 6 coats MINIMUM.
>
> HJ Wilke, NACE (National Association Of Corrosion Engineers)


Good information! Now I have a type of clear to look for. May have to
search outside Walmart, ha-ha, but it seems like a big difference in
quality if I can pull this 'touch up-grade' off cleanly.
 

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