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View Full Version : Lacquer thinner on gel coat


Steve Freeman
June 28th 07, 09:13 PM
Need to remove previous owners competition number. Would like to
confirm that lacquer thinner will not affect gel coat.

Capt. Geoffrey Thorpe
June 28th 07, 11:51 PM
"Steve Freeman" > wrote in message
ups.com...
> Need to remove previous owners competition number. Would like to
> confirm that lacquer thinner will not affect gel coat.
>

This sort of thing has come up before - I don't think that you are going to
get conformation that you will not affect gel coat with agressive solvents.

What kind of numbers are they? Vinyl comes off best with a hair dryer. 3M
also makes a rubber "eraser" wheel that goes on a drill motor to generate
heat and friction.

Paint is a whole 'nother story. Easy-off oven cleaner (the original kind
with Lye) has worked for me on boats - dunno if I have the guts to try it on
a structural laminate on an airplane. "Fiberglass safe" paint removers often
aren't (at least in my experience) - I've had them eat through gel coat
where some was spilled (Interlux "Pintoff" or something like that).

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

Capt. Geoffrey Thorpe
June 29th 07, 12:27 AM
> "Steve Freeman" > wrote in message
> ups.com...
>> Need to remove previous owners competition number. Would like to
>> confirm that lacquer thinner will not affect gel coat.
>>


<http://groups.google.com/group/rec.aviation.soaring/search?group=rec.aviation.soaring&q=adhesive+remove>

Yields at least a dozen threads on this topic

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

June 29th 07, 01:24 PM
On Jun 28, 4:13 pm, Steve Freeman > wrote:
> Need to remove previous owners competition number. Would like to
> confirm that lacquer thinner will not affect gel coat.

Try acetone. If numbers are typical nitrocellulose laquer used in the
old days, they will come off quickly and easily.
If acetone does not touch the paint, sand off starting with 600
sandpaper wet, followed by 1000, 1200, 1500, 2000 and polish. Takes
about 2-3 hr to do whole job right and no gelcoat damage.
Avoid the temptation to try for a chemical solution lest you next be
visiting an expert to put white chemicals back on.
Cheers
UH

Bill Daniels
June 29th 07, 02:36 PM
A lot of good discussion here but there one thing that hasn't been
mentioned. Old gelcoat can be very porous. Depending on the condition of
the underlying (and surrounding) gelcoat, disolving colored lacquer with a
thinner or solvent may cause it to soak it into porous gelcoat making a real
mess.

Sometimes, the old CN has shielded the underlying gelcoat from UV so trying
to remove the CN's with thinner just makes it soak into the surrounding
surface leaving hte CN's visible as white numbers on a stained background.

If this happens, the only recourse is to remove all the old gelcoat and
refinish. Lacquer really sticks to gelcoat - a good reason to use vinyl.
Proceed carefully with the CN removal job.

Bill Daniels


> wrote in message
ups.com...
> On Jun 28, 4:13 pm, Steve Freeman > wrote:
>> Need to remove previous owners competition number. Would like to
>> confirm that lacquer thinner will not affect gel coat.
>
> Try acetone. If numbers are typical nitrocellulose laquer used in the
> old days, they will come off quickly and easily.
> If acetone does not touch the paint, sand off starting with 600
> sandpaper wet, followed by 1000, 1200, 1500, 2000 and polish. Takes
> about 2-3 hr to do whole job right and no gelcoat damage.
> Avoid the temptation to try for a chemical solution lest you next be
> visiting an expert to put white chemicals back on.
> Cheers
> UH
>

Berry[_2_]
June 29th 07, 07:41 PM
In article >,
"Capt. Geoffrey Thorpe" <The Sea Hawk at wow way d0t com> wrote:

> > "Steve Freeman" > wrote in message
> > ups.com...
> >> Need to remove previous owners competition number. Would like to
> >> confirm that lacquer thinner will not affect gel coat.
> >>
>
>
> <http://groups.google.com/group/rec.aviation.soaring/search?group=rec.aviation
> .soaring&q=adhesive+remove>
>
> Yields at least a dozen threads on this topic
>
> --
> Geoff
> The Sea Hawk at Wow Way d0t Com
> remove spaces and make the obvious substitutions to reply by mail
> When immigration is outlawed, only outlaws will immigrate.

Here's what worked for me on my old 301 Libelle that had the original
grey lettering on the fuselage: Acetone. Lacquer thinner will work, but
it's the acetone in lacquer thinner that actually takes off the old
numbers. Just use acetone and the numbers will wipe right off very
easily. You will find however, that the gelcoat under the numbers looks
a lot better than the gelcoat that wasn't covered.

The acetone did not damage my gelcoat. It did not damage the composite
laminate. It may have damaged my liver, but it had to wait in line for
that...

Speaking of which, it's Friday and cocktail hour is approaching.

June 30th 07, 02:03 AM
On Jun 29, 11:41 am, Berry > wrote:
> In article >,
> "Capt. Geoffrey Thorpe" <The Sea Hawk at wow way d0t com> wrote:
>
>
>
>
>
> > > "Steve Freeman" > wrote in message
> > ups.com...
> > >> Need to remove previous owners competition number. Would like to
> > >> confirm that lacquer thinner will not affect gel coat.
>
> > <http://groups.google.com/group/rec.aviation.soaring/search?group=rec....
> > .soaring&q=adhesive+remove>
>
> > Yields at least a dozen threads on this topic
>
> > --
> > Geoff
> > The Sea Hawk at Wow Way d0t Com
> > remove spaces and make the obvious substitutions to reply by mail
> > When immigration is outlawed, only outlaws will immigrate.
>
> Here's what worked for me on my old 301 Libelle that had the original
> grey lettering on the fuselage: Acetone. Lacquer thinner will work, but
> it's the acetone in lacquer thinner that actually takes off the old
> numbers. Just use acetone and the numbers will wipe right off very
> easily. You will find however, that the gelcoat under the numbers looks
> a lot better than the gelcoat that wasn't covered.
>
> The acetone did not damage my gelcoat. It did not damage the composite
> laminate. It may have damaged my liver, but it had to wait in line for
> that...
>
> Speaking of which, it's Friday and cocktail hour is approaching.- Hide quoted text -
>
> - Show quoted text -

I agree with Bill that the lacquer make get into the surrounding
gelcoat. I Disagree that the only thing to do is sand down all the
old gelcoat. How about appropriate surface prep, then a new white
background in a matching white Polyurethane or even a coat of
Lacquer.
OR
My Speed Astir had the Standard Grob orange trim on the nose. I used
Acetone to remove the bulk of the paint, then sanded for a while with
1200 grit, which took care of the rest, then buffed out and waxed.
Aside from looking slightly too clean and shiny, it's unnoticeable.
YMMV, the Grob has very thick gelcoat.

Jim

Chip Bearden
July 3rd 07, 04:39 AM
I agree with UH. Sanding isn't much work, even on the wings. Do a
contour job on the lower wing and most of the ID number there will
likely sand off anyway. :)

I used polishing/rubbing compound (can't remember which; whatever I
had handy that day) and elbow grease to convert an old N number and
contest number from JB to JE for the new buyer. It really wasn't too
bad. The only problem was, as one poster has noted, the gel coat under
the numbers was in "like new" condition after 13 years: no crazing and
no discoloration, neither of which was true of the rest of the
airplane. Makes you wonder if you should wait a year or three for the
shrinkage to stablize on a new glider, sand it smooth, and then shoot
it with a coat of polyurethane or something else on top of the gel
coat.

Chip Bearden
ASW 24 "JB"
USA

Shawn[_3_]
July 3rd 07, 05:34 PM
Chip Bearden wrote:
> I agree with UH. Sanding isn't much work, even on the wings. Do a
> contour job on the lower wing and most of the ID number there will
> likely sand off anyway. :)
>
> I used polishing/rubbing compound (can't remember which; whatever I
> had handy that day) and elbow grease to convert an old N number and
> contest number from JB to JE for the new buyer. It really wasn't too
> bad. The only problem was, as one poster has noted, the gel coat under
> the numbers was in "like new" condition after 13 years: no crazing and
> no discoloration, neither of which was true of the rest of the
> airplane. Makes you wonder if you should wait a year or three for the
> shrinkage to stablize on a new glider, sand it smooth, and then shoot
> it with a coat of polyurethane or something else on top of the gel
> coat.

Indeed. Maybe the ships should be painted contest letter gray, with
stencils in place on the fin and under the wing so the letters show up
white.
The Ad will say "No gel coat cracking or crazing except contest numbers"
:-)


Shawn

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