Advise wanted for maintaining gelcoat that is already FUBAR

One other thing to add, I know there are some people out there flying glass ships with pretty worn out finishes. What are your thoughts?
I've read about the gelcoat cracks continuing into the fiberglass, but I've also read about people saying they've never seen that in a career of refinishing sailplanes.
The appearance and performance degradation (which seems to be minor if not at all from SeeYou analysis) of my my finish doesn't bother me, but the idea that it would impact the safety of the glider does. Nonetheless, I feel if this were really an issue with safety, we would have seen a structural failure of a wing given how many sailplanes are out there with cracking gelcoat. To my knowledge we have not.

One other question, where's the best place to find "white catalyst" previously mentioned, come to think of it I don't even know what that is!

There are a number of publications on gelcoat cracking by respectable
manufacturers (DG, Schempp-Hirth, Schleicher), check their websites.
Various manufacturers have very specific demands of what is tolerable or
not. I would say that common sense alone would dictate this particular
glider be given a strip-back to GRP then refinished. Wouldn't be surprised
if some glassfibre damage turned up.

On Wednesday, 8 April 2015 12:53:22 UTC+2, PBA wrote:
One other thing to add, I know there are some people out there flying glass ships with pretty worn out finishes. What are your thoughts?
I've read about the gelcoat cracks continuing into the fiberglass, but I've also read about people saying they've never seen that in a career of refinishing sailplanes.

I recently chatted to a local aircraft repairer regarding gelcoat damage and flying it with the existing damage.
His take is that the damage will progress if you're flying in wet and freezing conditions because moisture gets into the cracks and makes them run as well as extend further down into the first layer of epoxy and finally the glass.

Personally I'd rather fork out the money and get it fixed before it becomes a more expensive repair (replacing first layer of glass).
There's also the pride aspect about flying something that looks like it has been looked after and not dragged out of a rubbish dump.

вторник, 7 апрел� 2015 г., 21:55:37 UTC+4 пользователь PBA напи�ал:
Thanks for taking a look.
Pictures are linked below.
The story goes this poor glider sat in a trailer for some years in Texas and it ate the otherwise bulletproof gelcoat.

Per usual the tops of the wings are the worst. Some of the sanding has gotten down to the gray layer that covers the fiberglass. Deep crazing/cracking in the gelcoat covers most of the upper surfaces of the glider.

I have no interest in a refinish at this time.



Perhaps I should just do nothing, but you can feel the "roughness" of the gelcoat when you run your hand along the wings. I was thinking I could improve this with some fine grit block sanding? What grit and what combination? Perhaps just a rubbing compound with an orbital sander?

I'm looking for advise on the best way to slow the destruction of the gelcoat. I know there is no saving it.

I'm thinking some form of block sanding to level the gelcoast as best I can and then waxing to prevent more moisture ingress?

Some have suggested spray paint to cover the bare spots, others have suggested gel coat patch for that?

Hoping for more discussion than flaming...


LINK TO PHOTOS: http://s35.photobucket.com/user/pba1...0Finish%202015

Здрав�твуйте!!
Я из СССÐ* и Ваши беды мне понÑ�тны.
Заходите вот �юда - и мы Вам поможем.
https://groups.google.com/forum/#!forum/1235677

On Tuesday, April 7, 2015 at 11:28:53 PM UTC-4, PBA wrote:
Charlie,
When you say "doing a bit" now can forestall the "complete refinish" what does that mean?
Thanks for the responses.
It seems like everyone is saying don't do anything but refinish it.
I hear that.
JJ and I live on opposite coasts, what's the best way to get the glider out there if driving it myself is not an option?

At a minimum, a GOOD coat of wax (after a wash & dry) can help seal the gelcoat surface to slow aging.
A bit better is to wetsand the gelcoat to "smooth" followed by a good hardwax application.
You will regain some of your glider performance (smooth is better than crack ridges) and the wax seals the surface.

At some point, the gelcoat really needs to be removed and replaced. It's not an easy job (dusty, dirty, labor intensive) thus the cost can be high.
Sanding gelcoat (from ~midway through a refinish to final sanding) is sorta like "trying to polish granite with wet toilet paper". It's just time consuming.

We just did a "sand and hardwax polish" on a ship with crazed gelcoat. It looks a lot better, smoother and more uniform in color, and may go another 1-2+ years before ending up where it was. It's also more likely to get regular washes and soft wax (which helps).
In the end, it will need a full refinish since ANYTHING put on top will just crack yet again where there are existing cracks.

If you want the ship trailered across the country, there are people in soaring that do it for a "living". Sometimes they take a ship one way, another one back instead of going empty.

On Wednesday, April 8, 2015 at 10:15:47 AM UTC-4, Charlie M. (UH & 002 owner/pilot) wrote:
On Tuesday, April 7, 2015 at 11:28:53 PM UTC-4, PBA wrote:
Charlie,
When you say "doing a bit" now can forestall the "complete refinish" what does that mean?
Thanks for the responses.
It seems like everyone is saying don't do anything but refinish it.
I hear that.
JJ and I live on opposite coasts, what's the best way to get the glider out there if driving it myself is not an option?

At a minimum, a GOOD coat of wax (after a wash & dry) can help seal the gelcoat surface to slow aging.
A bit better is to wetsand the gelcoat to "smooth" followed by a good hardwax application.
You will regain some of your glider performance (smooth is better than crack ridges) and the wax seals the surface.

At some point, the gelcoat really needs to be removed and replaced. It's not an easy job (dusty, dirty, labor intensive) thus the cost can be high.
Sanding gelcoat (from ~midway through a refinish to final sanding) is sorta like "trying to polish granite with wet toilet paper". It's just time consuming.

We just did a "sand and hardwax polish" on a ship with crazed gelcoat. It looks a lot better, smoother and more uniform in color, and may go another 1-2+ years before ending up where it was. It's also more likely to get regular washes and soft wax (which helps).
In the end, it will need a full refinish since ANYTHING put on top will just crack yet again where there are existing cracks.

If you want the ship trailered across the country, there are people in soaring that do it for a "living". Sometimes they take a ship one way, another one back instead of going empty.

DO NOT WAX in its current condition. i would strongly advise agaist that. there is too much fiberglass exposed and it could lead to problems during the refinish that could compromise paint adhesion. heavy sand and polish on my glider to hold the wings over for one year while we refinished the fuselage, and did not wax. our crazing was not as advanced as yours, and wasn't peeling but i wasn't taking any chances. that's my only disagreement.

On Wednesday, April 8, 2015 at 6:53:22 AM UTC-4, PBA wrote:
One other thing to add, I know there are some people out there flying glass ships with pretty worn out finishes. What are your thoughts?
I've read about the gelcoat cracks continuing into the fiberglass, but I've also read about people saying they've never seen that in a career of refinishing sailplanes.
The appearance and performance degradation (which seems to be minor if not at all from SeeYou analysis) of my my finish doesn't bother me, but the idea that it would impact the safety of the glider does. Nonetheless, I feel if this were really an issue with safety, we would have seen a structural failure of a wing given how many sailplanes are out there with cracking gelcoat. To my knowledge we have not.

One other question, where's the best place to find "white catalyst" previously mentioned, come to think of it I don't even know what that is!

the cracks don't manifest themselves in the same way when they continue into the glass. they simply appear as faint white lines in the glass, running in the same direction as the crazing. it definitely happens, and there is more than one way to deal with it.

Todd at Yankee Composites finished up the wings on my Duo in January.

They weren't as bad as the original poster, but they had serious cracks in the gelcoat. I had bought myself some time by wet sanding the wings annually and filling a few chips, but I knew it was terminal for the gel coat.

As to performance, I don't think it makes enough of a difference to notice.

One year at our contest, the cracks had lifted over winter and I hadn't yet sanded them down. One morning I wet sanded the right wing. Flew 500k with the asymmetric sanding. Could not notice a thing, aside from the right wing looking smoother.

Sanded the other wing the next morning since smooth feels better, but no turning or yaw tendencies were noticeable which I was a little surprised at.

ND is correct, the cracks will propagate down to the glass and will be visible as little lines. Todd sanded down to the finish glass and then applied a very thin veil cloth to present a new crack free surface to spray on the new Polyurethane system on.

The results are gorgeous.

I put a few pictures of the process up include a shot of what the cracks look like when they hit the glass.

https://plus.google.com/u/0/10847298...7 63833362098

Morgan

On Wednesday, April 8, 2015 at 8:31:21 AM UTC-7, ND wrote:
On Wednesday, April 8, 2015 at 6:53:22 AM UTC-4, PBA wrote:
One other thing to add, I know there are some people out there flying glass ships with pretty worn out finishes. What are your thoughts?
I've read about the gelcoat cracks continuing into the fiberglass, but I've also read about people saying they've never seen that in a career of refinishing sailplanes.
The appearance and performance degradation (which seems to be minor if not at all from SeeYou analysis) of my my finish doesn't bother me, but the idea that it would impact the safety of the glider does. Nonetheless, I feel if this were really an issue with safety, we would have seen a structural failure of a wing given how many sailplanes are out there with cracking gelcoat. To my knowledge we have not.

One other question, where's the best place to find "white catalyst" previously mentioned, come to think of it I don't even know what that is!

the cracks don't manifest themselves in the same way when they continue into the glass. they simply appear as faint white lines in the glass, running in the same direction as the crazing. it definitely happens, and there is more than one way to deal with it.

I've done (together with somebody else) replacement of the top glass on a
Cirrus, both wings top surfaces, due to advanced gelcoat cracking going
into the skins. Trust me: you don't want to go there.

At 15:31 08 April 2015, ND wrote:
On Wednesday, April 8, 2015 at 6:53:22 AM UTC-4, PBA wrote:
One other thing to add, I know there are some people out there flying
gla=
ss ships with pretty worn out finishes. What are your thoughts?
I've read about the gelcoat cracks continuing into the fiberglass, but
I'=
ve also read about people saying they've never seen that in a career of
ref=
inishing sailplanes.=20
The appearance and performance degradation (which seems to be minor if
no=
t at all from SeeYou analysis) of my my finish doesn't bother me, but the
i=
dea that it would impact the safety of the glider does. Nonetheless, I
feel=
if this were really an issue with safety, we would have seen a
structural
=
failure of a wing given how many sailplanes are out there with cracking
gel=
coat. To my knowledge we have not.=20
=20
One other question, where's the best place to find "white catalyst"
previ=
ously mentioned, come to think of it I don't even know what that is!

the cracks don't manifest themselves in the same way when they continue
int=
o the glass. they simply appear as faint white lines in the glass,
running
=
in the same direction as the crazing. it definitely happens, and there is
m=
ore than one way to deal with it.

I am sorry, remind me again why PIK gliders and glass sailboat do not have crazing and cracking problems, yet expensive German gliders do?!