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Spraying Metallic - Help....!

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  #1  
Old   
Steve Walker
 
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Default Spraying Metallic - Help....! - 03-04-2007 , 03:30 PM






Hi -

Needed to replace my roof-mounted carphone aerial recently, after it lost a
fight with a low-hanging branch. Decided to mount the replacement further
back on clean undisturbed steel, and do a filler repair on the distorted
hole left by the old one. I managed a lovely smooth repair with
mesh-reinforced Plastic Padding, sanded off with 1200 wet & dry. Went out
and bought a specially-mixed exact-match aerosol of dark blue paint, but now
I just can't get any kind of half-decent paint finish over it.

I masked off the area (approx playing card sized), and applied about 6-8
light sprays (with 10min intervals to allow it to go tacky). Left this for
a week to harden off, and you could easily see boundaries where one spray
run had overlapped another etc. Got the metallic T-Cut out to blend it
yesterday, only to find that this removed the colour layer! I was just
left with a really weird silvery / undercoaty patch.

Tried to spray again today, but I can't apply it softly enough to avoid
obvious layers. I assume that this will mean polishing again, which will
remove the colour again. The area needing respray is now an inch wider on
all sides, and it's going to grow each time I get it wrong.

A quick scamper around google suggests that it's practically impossible to
spray a small section of car body, especially with a standard aerosol can,
and the whole panel usually has to be redone. Can't believe this - surely
there's some way to get a *reasonable* finish? I don't want concours, just
a smooth, more or less matching result.

I'm now torn between buying a little airbrush kit to see if an accurate,
gentle & slow application works any better, or else calling in one of those
cosmetic repair firms from the yellow pages.

Any advice would be gratefully appreciated!

Thanks -
Steve



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  #2  
Old   
Martin
 
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Default Re: Spraying Metallic - Help....! - 03-04-2007 , 03:33 PM








Steve Walker wrote:
Quote:
Hi -

Needed to replace my roof-mounted carphone aerial recently, after it
lost a fight with a low-hanging branch. Decided to mount the
replacement further back on clean undisturbed steel, and do a filler
repair on the distorted hole left by the old one. I managed a
lovely smooth repair with mesh-reinforced Plastic Padding, sanded off
with 1200 wet & dry. Went out and bought a specially-mixed
exact-match aerosol of dark blue paint, but now I just can't get any
kind of half-decent paint finish over it.

I masked off the area (approx playing card sized), and applied about
6-8 light sprays (with 10min intervals to allow it to go tacky).
Left this for a week to harden off, and you could easily see
boundaries where one spray run had overlapped another etc. Got the
metallic T-Cut out to blend it yesterday, only to find that this
removed the colour layer! I was just left with a really weird
silvery / undercoaty patch.

Tried to spray again today, but I can't apply it softly enough to
avoid obvious layers. I assume that this will mean polishing again,
which will remove the colour again. The area needing respray is now
an inch wider on all sides, and it's going to grow each time I get it
wrong.

A quick scamper around google suggests that it's practically
impossible to spray a small section of car body, especially with a
standard aerosol can, and the whole panel usually has to be redone.
Can't believe this - surely there's some way to get a *reasonable*
finish? I don't want concours, just a smooth, more or less matching
result.

I'm now torn between buying a little airbrush kit to see if an
accurate, gentle & slow application works any better, or else calling
in one of those cosmetic repair firms from the yellow pages.

Any advice would be gratefully appreciated!

Thanks -
Steve

You need to check this, but I've only come across 2-pack metallic finishes:
the metallic paint and a clear laquer finish. I don't know if modern
finishes are similarly 2-pack or if there is any laquer in the aerosol you
were given, but from the sound of it, you haven't been told to finish off
with a spray coat from a can of clear laquer. You should be able to
get the laquer from the same supplier as the base coat to ensure
compatibility. Then, by all means, use T-Cut to blend/polish the
laquer.

Does this make sense?

Martin




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  #3  
Old   
Steve Walker
 
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Default Re: Spraying Metallic - Help....! - 03-04-2007 , 04:37 PM



Martin wrote:
Quote:
Steve Walker wrote:
I masked off the area (approx playing card sized), and applied about
6-8 light sprays (with 10min intervals to allow it to go tacky).
Left this for a week to harden off, and you could easily see
boundaries where one spray run had overlapped another etc. Got the
metallic T-Cut out to blend it yesterday, only to find that this
removed the colour layer! I was just left with a really weird
silvery / undercoaty patch.

Tried to spray again today, but I can't apply it softly enough to
avoid obvious layers. I assume that this will mean polishing again,
which will remove the colour again. The area needing respray is now
an inch wider on all sides, and it's going to grow each time I get it
wrong.

You need to check this, but I've only come across 2-pack metallic
finishes: the metallic paint and a clear laquer finish. I don't
know if modern finishes are similarly 2-pack or if there is any
laquer in the aerosol you were given, but from the sound of it, you
haven't been told to finish off with a spray coat from a can of clear
laquer. You should be able to get the laquer from the same
supplier as the base coat to ensure compatibility. Then, by all
means, use T-Cut to blend/polish the laquer.

Does this make sense?
Yeah, it does - thanks for this Martin.

I've seen the clear lacquer coat referred to, but assumed I didn't need it.
The aerosol gives a lovely finish without it - I checked a piece of the
oversprayed masking paper against the car body and the match was perfect.
But now I'm wondering if the lacquer would help - gotta be worth a try for a
fiver.





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  #4  
Old   
Doki
 
Posts: n/a

Default Re: Spraying Metallic - Help....! - 03-04-2007 , 04:47 PM




"Steve Walker" <spam-trap (AT) beeb (DOT) net> wrote

Quote:
Hi -

Needed to replace my roof-mounted carphone aerial recently, after it lost
a fight with a low-hanging branch. Decided to mount the replacement
further back on clean undisturbed steel, and do a filler repair on the
distorted hole left by the old one. I managed a lovely smooth repair
with mesh-reinforced Plastic Padding, sanded off with 1200 wet & dry.
Went out and bought a specially-mixed exact-match aerosol of dark blue
paint, but now I just can't get any kind of half-decent paint finish over
it.

I masked off the area (approx playing card sized), and applied about 6-8
light sprays (with 10min intervals to allow it to go tacky). Left this
for a week to harden off, and you could easily see boundaries where one
spray run had overlapped another etc. Got the metallic T-Cut out to
blend it yesterday, only to find that this removed the colour layer! I
was just left with a really weird silvery / undercoaty patch.

Tried to spray again today, but I can't apply it softly enough to avoid
obvious layers. I assume that this will mean polishing again, which will
remove the colour again. The area needing respray is now an inch wider on
all sides, and it's going to grow each time I get it wrong.

A quick scamper around google suggests that it's practically impossible to
spray a small section of car body, especially with a standard aerosol can,
and the whole panel usually has to be redone. Can't believe this - surely
there's some way to get a *reasonable* finish? I don't want concours,
just a smooth, more or less matching result.

I'm now torn between buying a little airbrush kit to see if an accurate,
gentle & slow application works any better, or else calling in one of
those cosmetic repair firms from the yellow pages.

Any advice would be gratefully appreciated!
You need to bear in mind that aerosol paint is very thin compared to paint
you'd actually put through a spraygun due to the propellant and the lack of
pressure pushing it out. I'd be very tempted to put a heavy coat on - it's a
roof, it shouldn't run unless you go really mad. And all metallic finishes
I've seen in aerosols need a lacquer coat. This is good, because it helps
you hide the repair. Cover more than the sprayed area with lacquer, then
polish it up. Be very wary of polishing aerosol paint for a good while (a
warm week later say). I'd also avoid trying to mask the immediate area -
mask most of the rest of the roof, but leave a good area around where you're
spraying unmasked, to avoid masking lines, then polish out any overspray.

Aerosol paint is definately not 2 pack btw - 2 pack is paint that's mixed
with a hardener to make it set.



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  #5  
Old   
Steve Walker
 
Posts: n/a

Default Re: Spraying Metallic - Help....! - 03-04-2007 , 05:00 PM



Doki wrote:
Quote:
"Steve Walker" <spam-trap (AT) beeb (DOT) net> wrote in message
news:550s3tF22rftvU1 (AT) mid (DOT) individual.net...
Hi -

Needed to replace my roof-mounted carphone aerial recently, after it
lost a fight with a low-hanging branch. Decided to mount the
replacement further back on clean undisturbed steel, and do a filler
repair on the distorted hole left by the old one. I managed a
lovely smooth repair with mesh-reinforced Plastic Padding, sanded
off with 1200 wet & dry. Went out and bought a specially-mixed
exact-match aerosol of dark blue paint, but now I just can't get any
kind of half-decent paint finish over it.

You need to bear in mind that aerosol paint is very thin compared to
paint you'd actually put through a spraygun due to the propellant and
the lack of pressure pushing it out. I'd be very tempted to put a
heavy coat on - it's a roof, it shouldn't run unless you go really
mad. And all metallic finishes I've seen in aerosols need a lacquer
coat. This is good, because it helps you hide the repair. Cover more
than the sprayed area with lacquer, then polish it up. Be very wary
of polishing aerosol paint for a good while (a warm week later say).
I'd also avoid trying to mask the immediate area - mask most of the
rest of the roof, but leave a good area around where you're spraying
unmasked, to avoid masking lines, then polish out any overspray.
Aerosol paint is definately not 2 pack btw - 2 pack is paint that's
mixed with a hardener to make it set.
Thanks Doki, that almost inspires me to have one more go.... )




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  #6  
Old   
Doki
 
Posts: n/a

Default Re: Spraying Metallic - Help....! - 03-04-2007 , 05:02 PM




"Steve Walker" <spam-trap (AT) beeb (DOT) net> wrote

Quote:
Doki wrote:
"Steve Walker" <spam-trap (AT) beeb (DOT) net> wrote in message
news:550s3tF22rftvU1 (AT) mid (DOT) individual.net...
Hi -

Needed to replace my roof-mounted carphone aerial recently, after it
lost a fight with a low-hanging branch. Decided to mount the
replacement further back on clean undisturbed steel, and do a filler
repair on the distorted hole left by the old one. I managed a
lovely smooth repair with mesh-reinforced Plastic Padding, sanded
off with 1200 wet & dry. Went out and bought a specially-mixed
exact-match aerosol of dark blue paint, but now I just can't get any
kind of half-decent paint finish over it.

You need to bear in mind that aerosol paint is very thin compared to
paint you'd actually put through a spraygun due to the propellant and
the lack of pressure pushing it out. I'd be very tempted to put a
heavy coat on - it's a roof, it shouldn't run unless you go really
mad. And all metallic finishes I've seen in aerosols need a lacquer
coat. This is good, because it helps you hide the repair. Cover more
than the sprayed area with lacquer, then polish it up. Be very wary
of polishing aerosol paint for a good while (a warm week later say).
I'd also avoid trying to mask the immediate area - mask most of the
rest of the roof, but leave a good area around where you're spraying
unmasked, to avoid masking lines, then polish out any overspray.
Aerosol paint is definately not 2 pack btw - 2 pack is paint that's
mixed with a hardener to make it set.

Thanks Doki, that almost inspires me to have one more go.... )
And you need to bear in mind that metallic finishes vary by thickness of
coat - thin, and all the metallic bits line up flat. Thicker and they end up
all angles...



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  #7  
Old   
MrCheerful
 
Posts: n/a

Default Re: Spraying Metallic - Help....! - 03-04-2007 , 05:16 PM




"Steve Walker" <spam-trap (AT) beeb (DOT) net> wrote

Quote:
Hi -

Needed to replace my roof-mounted carphone aerial recently, after it lost
a fight with a low-hanging branch. Decided to mount the replacement
further back on clean undisturbed steel, and do a filler repair on the
distorted hole left by the old one. I managed a lovely smooth repair
with mesh-reinforced Plastic Padding, sanded off with 1200 wet & dry.
Went out and bought a specially-mixed exact-match aerosol of dark blue
paint, but now I just can't get any kind of half-decent paint finish over
it.

I masked off the area (approx playing card sized), and applied about 6-8
light sprays (with 10min intervals to allow it to go tacky). Left this
for a week to harden off, and you could easily see boundaries where one
spray run had overlapped another etc. Got the metallic T-Cut out to
blend it yesterday, only to find that this removed the colour layer! I
was just left with a really weird silvery / undercoaty patch.

Tried to spray again today, but I can't apply it softly enough to avoid
obvious layers. I assume that this will mean polishing again, which will
remove the colour again. The area needing respray is now an inch wider on
all sides, and it's going to grow each time I get it wrong.

A quick scamper around google suggests that it's practically impossible to
spray a small section of car body, especially with a standard aerosol can,
and the whole panel usually has to be redone. Can't believe this - surely
there's some way to get a *reasonable* finish? I don't want concours,
just a smooth, more or less matching result.

I'm now torn between buying a little airbrush kit to see if an accurate,
gentle & slow application works any better, or else calling in one of
those cosmetic repair firms from the yellow pages.

Any advice would be gratefully appreciated!

Thanks -
Steve

very fine rubbing compound over the whole panel, very fine rub down over the
area, overlap the area with paint (no masking) do not flat , then lacquer
over a larger area.

Your chances of a good match are very low.

Mrcheerful




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  #8  
Old   
The Natural Philosopher
 
Posts: n/a

Default Re: Spraying Metallic - Help....! - 03-04-2007 , 05:37 PM



Steve Walker wrote:

Quote:
A quick scamper around google suggests that it's practically impossible to
spray a small section of car body, especially with a standard aerosol can,
and the whole panel usually has to be redone. Can't believe this - surely
there's some way to get a *reasonable* finish? I don't want concours, just
a smooth, more or less matching result.
Its doable with plain color, but you will never get a match with metallics.

Prep it up and take it to a pro spray place and get the whole panel done.

It wont cost that much..its the prepping up they charge for.




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  #9  
Old   
adder1969
 
Posts: n/a

Default Re: Spraying Metallic - Help....! - 03-05-2007 , 08:05 AM



On Mar 4, 11:48 pm, meow2... (AT) care2 (DOT) com wrote:
Quote:
On 4 Mar, 22:37, "Steve Walker" <spam-t... (AT) beeb (DOT) net> wrote:





Martin wrote:
Steve Walker wrote:
I masked off the area (approx playing card sized), and applied about
6-8 light sprays (with 10min intervals to allow it to go tacky).
Left this for a week to harden off, and you could easily see
boundaries where one spray run had overlapped another etc. Got the
metallic T-Cut out to blend it yesterday, only to find that this
removed the colour layer! I was just left with a really weird
silvery / undercoaty patch.

Tried to spray again today, but I can't apply it softly enough to
avoid obvious layers. I assume that this will mean polishing again,
which will remove the colour again. The area needing respray is now
an inch wider on all sides, and it's going to grow each time I get it
wrong.

You need to check this, but I've only come across 2-pack metallic
finishes: the metallic paint and a clear laquer finish. I don't
know if modern finishes are similarly 2-pack or if there is any
laquer in the aerosol you were given, but from the sound of it, you
haven't been told to finish off with a spray coat from a can of clear
laquer. You should be able to get the laquer from the same
supplier as the base coat to ensure compatibility. Then, by all
means, use T-Cut to blend/polish the laquer.

Does this make sense?

Yeah, it does - thanks for this Martin.

I've seen the clear lacquer coat referred to, but assumed I didn't need it.
The aerosol gives a lovely finish without it - I checked a piece of the
oversprayed masking paper against the car body and the match was perfect.
But now I'm wondering if the lacquer would help - gotta be worth a try for a
fiver.

metallic paint must have a clear lacquer topcoat, otherwise it
a) doesnt look gloss
b) is weak and scratches readily
c) the ali flakes oxidise, making it look an eyesore after a while.

But basically youve found out the hard way that patching metallic will
never work well. Either go with a straight hard edge, dont sand it,
and accept it, or respray the whole panel for a quality result. Theres
no way youre going to feather the stuff successfully.


Sometimes a thick or wet enough layer will dry smooth and glossy and
if you mask the area with the edges of the tape lifted up you can
sometimes confine the spray to the area without a hard edge line.

Alternatively put a contrasting stripe down the length of the roof or
a contrasting round dot so it looks like it's supposed to be there.



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  #10  
Old   
Chris Bartram
 
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Default Re: Spraying Metallic - Help....! - 03-05-2007 , 10:22 AM



adder1969 wrote:

Quote:
Sometimes a thick or wet enough layer will dry smooth and glossy and
if you mask the area with the edges of the tape lifted up you can
sometimes confine the spray to the area without a hard edge line.

A similar trick is to fold the tape back on itself to avoid the edge.


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