Gel Coat for Dummies

[Ray Lovinggood]

Help.

I want to repair some self-inflicted wounds on the
leading edges of the wings on my LS1-d. The wounds
were created when getting the wings out from and/or
putting them back into the definintely non-Cobra/Komet
trailer. While not a Cobra, it is a 'serpent' type
of trailer, but more of a intestinal 'tape worm'...

I scraped off little bits of gel coat from time to
time and I want to reapply gel coat. Fill the little
divots and sand them off.

But, how do you sand the leading edge? These divots
were probably no more than about 50 mm long for the
largest and no more than about 10 mm high, again for
the largest. Others are smaller. And, they are right
on the nose of the leading edges.

I've begun the work with some gel coat and I've sanded
it down, but wondering what the 'right' way would be.
What size sanding block to use? I'm using a milled
piece of wood that measures about 75mm wide by 15 mm
thick by about 450 mm long and wrapping a sheet of
sanding paper around it.

My sanding movements have been parallel with the leading
edge, trying to keep the sand paper right over the
gel coat which 'stands proud' above the surrounding
areas.

Any help will be appreciated.

Thanks,
Ray Lovinggood
Carrboro, North Carolina, USA

[KiloKilo]

There's a lot more in this article then you need ... you can actually
paint gelcoat with a brush for small LE repairs ... a sanding block/bar
is essential ... a small one is probably OK for small dings ... I use
longer for LE refinishing.

http://sailplane-racing.org/Articles/ASW20/asw20_wing.htm

KK

Ray Lovinggood wrote:
> Help.
>
> I want to repair some self-inflicted wounds on the
> leading edges of the wings on my LS1-d. The wounds
> were created when getting the wings out from and/or
> putting them back into the definintely non-Cobra/Komet

[KiloKilo]

Just to look at this a little more ... small fixes are often the most
difficult. As you sand down the newly applied material, you ultimately
hit the surrounding area and remove gelcoat there ... sometimes to the
point where the underlying darker glass surface starts to show. Except
for small chips, I always use some type of disclosure agent which shows
where I am sanding. I have also used tape to shield areas ... this can
help ... and always use the finest grit paper possible ... slower is
better. Leading edge sanding around the front radius requires feel and
wrist action ... it would be easier to explain on the phone if you want
to discuss.

KK

[[email protected]]

There is an excellent video series on gel coat repairs for the
fiberglass boat community. These will give you the general knowledge
you need. You can then use the group for the more specific knowledge of
work on sailplanes.

Cosmetic Gelcoat and Fiberglass Repair Volumes I-III
V I: Gelcoat 100 minutes
V II: Stress Cracks, Air Voids, and Fractures 104 minutes
V III: Color Matching 34 minutes
Bennett Marine Video 1989
Marina Del Ray, CA 90292

[Bob Gibbons]

Nothing new here, but what I do is use a short piece (6 inches) of 1
inch square aluminum bar stock. I put strips of various grades of
wet/dry sandpaper on each side. Say, 200grit, 400 grit, 600 grit, 1000
grit.

I support the wing leading edge down and paint on some matching
gelcoat. The leading edge down assures complete coverage of the
leading edge dings.

When the gelcoat hardens I use the multisided sanding bar to
progressively remove the higher material, using water and finer
sandpaper as I progress down.

Finish with polishing compound and wax.

Bob

On 12 Dec 2004 17:17:38 GMT, Ray Lovinggood
> wrote:

>Help.
>
>I want to repair some self-inflicted wounds on the
>leading edges of the wings on my LS1-d. The wounds
>were created when getting the wings out from and/or
>putting them back into the definintely non-Cobra/Komet
>trailer. While not a Cobra, it is a 'serpent' type
>of trailer, but more of a intestinal 'tape worm'...
>
>I scraped off little bits of gel coat from time to
>time and I want to reapply gel coat. Fill the little
>divots and sand them off.
>
>But, how do you sand the leading edge? These divots
>were probably no more than about 50 mm long for the
>largest and no more than about 10 mm high, again for
>the largest. Others are smaller. And, they are right
>on the nose of the leading edges.
>
>I've begun the work with some gel coat and I've sanded
>it down, but wondering what the 'right' way would be.
> What size sanding block to use? I'm using a milled
>piece of wood that measures about 75mm wide by 15 mm
>thick by about 450 mm long and wrapping a sheet of
>sanding paper around it.
>
>My sanding movements have been parallel with the leading
>edge, trying to keep the sand paper right over the
>gel coat which 'stands proud' above the surrounding
>areas.
>
>Any help will be appreciated.
>
>Thanks,
>Ray Lovinggood
>Carrboro, North Carolina, USA
>
>
>

[Tony Verhulst]

What, if anything, do you do about matching the shade of the existing
surface?

Tony V.
http://home.comcast.net/~verhulst/SOARING

[F.L. Whiteley]

Hopefully, basic white without tints.

Gels and Imron may discolor with age and environment. I had an Imron
painted Open Cirrus and tried very hard to match and sought 7 different
opinions before ordering, using the factory color charts. Under overcast
and blue sky and fluorescent lighting there was some divergence between a
light gray tint and a light blue tint. I went with the predominently female
opinions, since color vision deficiency is more generally a male trait.

It was a bit blue once applied, the gray may have worked better. However, I
had to order a minimum amount and when the person I sold my final share to
damaged the glider, the fuselage was re-sprayed with the remainder, so it
finally matched.

Frank Whiteley


"Tony Verhulst" > wrote in message
news:ld8vd.227573$HA.7445@attbi_s01...
> What, if anything, do you do about matching the shade of the existing
> surface?
>
> Tony V.
> http://home.comcast.net/~verhulst/SOARING

[Ray Lovinggood]

Tony,

That's the LEAST of my worries. :-)

Ray

At 04:30 13 December 2004, Tony Verhulst wrote:
>What, if anything, do you do about matching the shade
>of the existing
>surface?
>
>Tony V.
>http://home.comcast.net/~verhulst/SOARING
>

[Larry Goddard]

OK everyone, take a deep breath before responding how stupid my approach
is... I am fully aware of the potential damage that _could_ occur.

One method that I have used successfully doing similar things to my
wings is to use a _clean_ mill ******* file. I know, I know.... sounds
like heresy to lay a file on your wing but if you lay it flat, parallel
to the leading edge, it is possible to "file" down the proud portion of
the gelcoat without gouging into or scratching the existing gelcoat.
The file rides smoothly over the existing gelcoat but takes off the
excess new gelcoat. It takes a light sensitive touch but makes very
quick work of the job because the teeth of the file only catches on the
raised replacement gel coat.

Try at your own risk!!!

Larry Goddard
"01" USA



Ray Lovinggood wrote:

> Help.
>
> I want to repair some self-inflicted wounds on the
> leading edges of the wings on my LS1-d. The wounds
> were created when getting the wings out from and/or
> putting them back into the definintely non-Cobra/Komet
> trailer. While not a Cobra, it is a 'serpent' type
> of trailer, but more of a intestinal 'tape worm'...
>
> I scraped off little bits of gel coat from time to
> time and I want to reapply gel coat. Fill the little
> divots and sand them off.
>
> But, how do you sand the leading edge? These divots
> were probably no more than about 50 mm long for the
> largest and no more than about 10 mm high, again for
> the largest. Others are smaller. And, they are right
> on the nose of the leading edges.
>
> I've begun the work with some gel coat and I've sanded
> it down, but wondering what the 'right' way would be.
> What size sanding block to use? I'm using a milled
> piece of wood that measures about 75mm wide by 15 mm
> thick by about 450 mm long and wrapping a sheet of
> sanding paper around it.
>
> My sanding movements have been parallel with the leading
> edge, trying to keep the sand paper right over the
> gel coat which 'stands proud' above the surrounding
> areas.
>
> Any help will be appreciated.
>
> Thanks,
> Ray Lovinggood
> Carrboro, North Carolina, USA

[John Sinclair]

Actually that's a very good idea, Larry

We did just that when the repair shop was open ('76
to '96)

+ Scrub with acetone to remove wax and crud.

+ Sand edges with 600 to remove oxidized gelcoat (or
a yellow ring will be trapped at the edge of your repair)

+ Mask off and brush on several coats of gelcoat. Use
heat gun to make it dry faster (hair dryer works)

+ Remove high spots with a file, this works best on
straight sections, like leading edges.

+ Wet sand with a block (600 & 800)

+ Buff out with a wool pad and liquid buffing compound.

We called the above, 'Dings & Things' Every annual
came with a request to fix this ding and take a look
at ---------------------
Best if a reasonably clever owner does this on his
own.
Happy, Happy to all on ras,
JJ

At 06:30 22 December 2004, Larry Goddard wrote:
>OK everyone, take a deep breath before responding how
>stupid my approach
>is... I am fully aware of the potential damage that
>_could_ occur.
>
>One method that I have used successfully doing similar
>things to my
>wings is to use a _clean_ mill ******* file. I know,
>I know.... sounds
>like heresy to lay a file on your wing but if you lay
>it flat, parallel
>to the leading edge, it is possible to 'file' down
>the proud portion of
>the gelcoat without gouging into or scratching the
>existing gelcoat.
>The file rides smoothly over the existing gelcoat
>but takes off the
>excess new gelcoat. It takes a light sensitive touch
>but makes very
>quick work of the job because the teeth of the file
>only catches on the
>raised replacement gel coat.
>
>Try at your own risk!!!
>
>Larry Goddard
>'01' USA
>
>
>
>Ray Lovinggood wrote:
>
>> Help.
>>
>> I want to repair some self-inflicted wounds on the
>> leading edges of the wings on my LS1-d. The wounds
>> were created when getting the wings out from and/or
>> putting them back into the definintely non-Cobra/Komet
>> trailer. While not a Cobra, it is a 'serpent' type
>> of trailer, but more of a intestinal 'tape worm'...
>>
>> I scraped off little bits of gel coat from time to
>> time and I want to reapply gel coat. Fill the little
>> divots and sand them off.
>>
>> But, how do you sand the leading edge? These divots
>> were probably no more than about 50 mm long for the
>> largest and no more than about 10 mm high, again for
>> the largest. Others are smaller. And, they are right
>> on the nose of the leading edges.
>>
>> I've begun the work with some gel coat and I've sanded
>> it down, but wondering what the 'right' way would
>>be.
>> What size sanding block to use? I'm using a milled
>> piece of wood that measures about 75mm wide by 15
>>mm
>> thick by about 450 mm long and wrapping a sheet of
>> sanding paper around it.
>>
>> My sanding movements have been parallel with the leading
>> edge, trying to keep the sand paper right over the
>> gel coat which 'stands proud' above the surrounding
>> areas.
>>
>> Any help will be appreciated.
>>
>> Thanks,
>> Ray Lovinggood
>> Carrboro, North Carolina, USA
>
>

[[email protected]]

I use Prestec made by: Simtec Coatings
16666 Smoketree St.
Bldg A, Units 3-5
Hesperia, CA
92345 760-244-2774
Super white 2781 #3. They sell it in quarts. If your ship is quite
yellow, you can tint the Prestec with poly compatable tinting agent. Go
easy and stay on the lighter side of a perfect match. It will dry
darker and after a year or two the new paint will age and may become
darker than the origional.

Painting problems can drive one to drink. Driving while drunk can lead
to jail. Jail can lead to probation. One must check in with ones
probation officer every week or he will come looking for you on ras.
Happy, Happy to all on ras,
JJ


T o d d P a t t i s t wrote:
> John Sinclair > wrote:
>
> >+ Mask off and brush on several coats of gelcoat. Use
> >heat gun to make it dry faster (hair dryer works)
>
> Where do you buy your gelcoat? Brand? Color?

[B Lacovara]

Just a point of clarification - Technically the Simtec products, including
Prestec, are not gel coats, but rather top coats.

There are significant differences in the formulations of gel coat (made to be
applied in a mold) and top coats (designed to be applied as a secondary
coating).

With that said, these are good products for the purpose... they're just not gel
coats.

Bob

[Jim Phoenix]

Having used both 2781 and 2481, I prefer 2481 for touch-up and small jobs, a
bit thicker, doesn't flow real nice like 2781, but I find it builds up
better. Gelcoat is heavy and if I had to do it all over again, I'd use
polyurethane or some other durable paint. I used insignia white Aerothane
brand polyurethane on the elevators to keep the weight down after filling in
the undercamber - it matches the 2781 on the horizontal perfectly - still
matches after 3 years. Unless you're doing a re-finish, you'll be
hard-pressed to use a fraction of an entire quart on touch-ups - but that's
the minimum quantity. The Simtec guys are very helpful and responsive in my
experience.

Jim

> wrote in message
ups.com...
>I use Prestec made by: Simtec Coatings
> 16666 Smoketree St.
> Bldg A, Units 3-5
> Hesperia, CA
> 92345 760-244-2774
> Super white 2781 #3. They sell it in quarts. If your ship is quite
> yellow, you can tint the Prestec with poly compatable tinting agent. Go
> easy and stay on the lighter side of a perfect match. It will dry
> darker and after a year or two the new paint will age and may become
> darker than the origional.
>
> Painting problems can drive one to drink. Driving while drunk can lead
> to jail. Jail can lead to probation. One must check in with ones
> probation officer every week or he will come looking for you on ras.
> Happy, Happy to all on ras,
> JJ
>
>
> T o d d P a t t i s t wrote:
>> John Sinclair > wrote:
>>
>> >+ Mask off and brush on several coats of gelcoat. Use
>> >heat gun to make it dry faster (hair dryer works)
>>
>> Where do you buy your gelcoat? Brand? Color?
>