View Full Version : Gel Coat Cracks or is it worse?
I'm looking at a glass ship to possibly buy that is in pretty good condition. The Gel coat was last done in 94 or so and is very white with no crazing.. The ship does have some cracks both on the bottom of the horizontal stab near the cutout for the attach post. It also has some near the trailing edge of the upper wing skins and also on the bottom wing skins. The cracks in the upper surfaces are centered in small depressions that almost look a well formed caulk line that was smoothed with a finger.(just a description of the shape not what I think was actually done) I'm guessing that someone in the past possibly tried to sand out some earlier cracking which later reappeared or possibly was filled with a filler that later shrunk. The cracks on the bottom of the wing are much longer cordwise but don't have the depressions like the ones on top.
Here is a link to a picture of the bottom of the tailplane.
http://www.flickr.com/photos/66126228@N08/7455559308/sizes/k/in/photostream/
Here is a link to a picture of the top of the wing skins.
http://www.flickr.com/photos/66126228@N08/7455558914/sizes/k/in/photostream/
I know how hard it is to judge this kind of thing from pictures but can any of you that have repaired things like this in the past take a guess as to weather this would be a simple cosmetic repair or does it look like some glass work would be required. I tried tapping adjacent to all the cracks and didn't find any areas that sounded any different than the rest of the wing.
Any comments or suggestions would be appreciated. Thanks.
sisu1a
June 27th 12, 06:52 PM
> I know how hard it is to judge this kind of thing from pictures but can any of you that have repaired things like this in the past take a guess as to weather this would be a simple cosmetic repair or does it look like some glass work would be required. I tried tapping adjacent to all the cracks and didn't find any areas that sounded any different than the rest of the wing.
>
> Any comments or suggestions would be appreciated. Thanks.
Not hard at all. That's some seriously shoddy work. Don't walk away,
run...
-p
Gary Adams
June 28th 12, 02:14 AM
On Wednesday, June 27, 2012 1:32:20 PM UTC-4, (unknown) wrote:
> I'm looking at a glass ship to possibly buy that is in pretty good condition. The Gel coat was last done in 94 or so and is very white with no crazing. The ship does have some cracks both on the bottom of the horizontal stab near the cutout for the attach post. It also has some near the trailing edge of the upper wing skins and also on the bottom wing skins. The cracks in the upper surfaces are centered in small depressions that almost look a well formed caulk line that was smoothed with a finger.(just a description of the shape not what I think was actually done) I'm guessing that someone in the past possibly tried to sand out some earlier cracking which later reappeared or possibly was filled with a filler that later shrunk. The cracks on the bottom of the wing are much longer cordwise but don't have the depressions like the ones on top.
>
> Here is a link to a picture of the bottom of the tailplane.
> http://www.flickr.com/photos/66126228@N08/7455559308/sizes/k/in/photostream/
>
> Here is a link to a picture of the top of the wing skins.
> http://www.flickr.com/photos/66126228@N08/7455558914/sizes/k/in/photostream/
>
> I know how hard it is to judge this kind of thing from pictures but can any of you that have repaired things like this in the past take a guess as to weather this would be a simple cosmetic repair or does it look like some glass work would be required. I tried tapping adjacent to all the cracks and didn't find any areas that sounded any different than the rest of the wing.
>
> Any comments or suggestions would be appreciated. Thanks.
What's the plane? Those pics show it's anything but in "Pretty good condition". Agree with Paul......That "horse has been rode hard, put up wet".
Gary Adams - GB
It's a Kestrel. I realize that these will need to be repaired at some point if not right away and the negotiations would take that into account. That's why I'm looking for more informed opinions. By pretty good shape I was basically referring to the overall condition other than these cracks. The rest of the gel looks quite amazing considering the age and compared to some other ships I've inspected with much more recent finishes. The rest of the ship's gel is so good that it would be a real shame to have to refinish the enitre wings and tailplane just to fix these localized cracks. Yes there are cracks. All of the ones on the tail are pictured and there are maybe 6 or so on each wing. I'd just like to get a better idea of what kind of repairs I might be looking at if I were to purchase the ship. However as I mentioned it's very hard to tell in person without being able to dig deeper, let alone by looking at some pictures online. Thanks for the help.
JJ Sinclair[_2_]
June 28th 12, 02:17 PM
On Wednesday, June 27, 2012 10:32:20 AM UTC-7, (unknown) wrote:
> I'm looking at a glass ship to possibly buy that is in pretty good condition. The Gel coat was last done in 94 or so and is very white with no crazing. The ship does have some cracks both on the bottom of the horizontal stab near the cutout for the attach post. It also has some near the trailing edge of the upper wing skins and also on the bottom wing skins. The cracks in the upper surfaces are centered in small depressions that almost look a well formed caulk line that was smoothed with a finger.(just a description of the shape not what I think was actually done) I'm guessing that someone in the past possibly tried to sand out some earlier cracking which later reappeared or possibly was filled with a filler that later shrunk. The cracks on the bottom of the wing are much longer cordwise but don't have the depressions like the ones on top.
>
> Here is a link to a picture of the bottom of the tailplane.
> http://www.flickr.com/photos/66126228@N08/7455559308/sizes/k/in/photostream/
>
> Here is a link to a picture of the top of the wing skins.
> http://www.flickr.com/photos/66126228@N08/7455558914/sizes/k/in/photostream/
>
> I know how hard it is to judge this kind of thing from pictures but can any of you that have repaired things like this in the past take a guess as to weather this would be a simple cosmetic repair or does it look like some glass work would be required. I tried tapping adjacent to all the cracks and didn't find any areas that sounded any different than the rest of the wing.
>
> Any comments or suggestions would be appreciated. Thanks.
Considering that the re-finish is 18 years old, I don't think those cracks are all that bad and I would expect to see some just like that on any 18 year old bird. Are they a structural problem? No Can they be fixed? Yes I would think a hungry repair shop would do a local grind-out, fill & re-finish for a couple thousand bucks. Nobody want's to do what we call "dings & things", but when there's nothing else in the shop...................
Just my opinion,
JJ
On Thursday, June 28, 2012 7:17:32 AM UTC-6, JJ Sinclair wrote:
> On Wednesday, June 27, 2012 10:32:20 AM UTC-7, (unknown) wrote:
> > I'm looking at a glass ship to possibly buy that is in pretty good condition. The Gel coat was last done in 94 or so and is very white with no crazing. The ship does have some cracks both on the bottom of the horizontal stab near the cutout for the attach post. It also has some near the trailing edge of the upper wing skins and also on the bottom wing skins. The cracks in the upper surfaces are centered in small depressions that almost look a well formed caulk line that was smoothed with a finger.(just a description of the shape not what I think was actually done) I'm guessing that someone in the past possibly tried to sand out some earlier cracking which later reappeared or possibly was filled with a filler that later shrunk. The cracks on the bottom of the wing are much longer cordwise but don't have the depressions like the ones on top.
> >
> > Here is a link to a picture of the bottom of the tailplane.
> > http://www.flickr.com/photos/66126228@N08/7455559308/sizes/k/in/photostream/
> >
> > Here is a link to a picture of the top of the wing skins.
> > http://www.flickr.com/photos/66126228@N08/7455558914/sizes/k/in/photostream/
> >
> > I know how hard it is to judge this kind of thing from pictures but can any of you that have repaired things like this in the past take a guess as to weather this would be a simple cosmetic repair or does it look like some glass work would be required. I tried tapping adjacent to all the cracks and didn't find any areas that sounded any different than the rest of the wing.
> >
> > Any comments or suggestions would be appreciated. Thanks.
>
> Considering that the re-finish is 18 years old, I don't think those cracks are all that bad and I would expect to see some just like that on any 18 year old bird. Are they a structural problem? No Can they be fixed? Yes I would think a hungry repair shop would do a local grind-out, fill & re-finish for a couple thousand bucks. Nobody want's to do what we call "dings & things", but when there's nothing else in the shop...................
> Just my opinion,
> JJ
JJ,
I looked at the pictures and the thing I was wondering is why are the cracks on the wing not straight. Don't most cracks follow the weave of the fabric or run in straight lines. The cracks Ive seen do. Just wondering, Thanks.
> Considering that the re-finish is 18 years old, I don't think those cracks are all that bad and I would expect to see some just like that on any 18 year old bird. Are they a structural problem? No Can they be fixed? Yes I would think a hungry repair shop would do a local grind-out, fill & re-finish for a couple thousand bucks. Nobody want's to do what we call "dings & things", but when there's nothing else in the shop...................
> Just my opinion,
> JJ
JJ,
Thanks for weighing in on this. Funny thing is your name is in the log book for contouring the wings, replacing the aileron drives and the annuals from 1981-1983. What a small world. The last refinish was actually in 1996 after looking back at the log scans.
In your opinion do you think a shop familiar with gliders would have a problem signing off an annual with these cracks or would they have to be repaired first? Thanks for your input, my composite experience is woefully lacking so having experienced eyes look at this helps a bunch.
Peter Scholz[_3_]
June 28th 12, 07:44 PM
Am 27.06.2012 19:32, wrote:
> I'm looking at a glass ship to possibly buy that is in pretty good condition. The Gel coat was last done in 94 or so and is very white with no crazing. The ship does have some cracks both on the bottom of the horizontal stab near the cutout for the attach post. It also has some near the trailing edge of the upper wing skins and also on the bottom wing skins. The cracks in the upper surfaces are centered in small depressions that almost look a well formed caulk line that was smoothed with a finger.(just a description of the shape not what I think was actually done) I'm guessing that someone in the past possibly tried to sand out some earlier cracking which later reappeared or possibly was filled with a filler that later shrunk. The cracks on the bottom of the wing are much longer cordwise but don't have the depressions like the ones on top.
>
> Here is a link to a picture of the bottom of the tailplane.
> http://www.flickr.com/photos/66126228@N08/7455559308/sizes/k/in/photostream/
>
> Here is a link to a picture of the top of the wing skins.
> http://www.flickr.com/photos/66126228@N08/7455558914/sizes/k/in/photostream/
>
> I know how hard it is to judge this kind of thing from pictures but can any of you that have repaired things like this in the past take a guess as to weather this would be a simple cosmetic repair or does it look like some glass work would be required. I tried tapping adjacent to all the cracks and didn't find any areas that sounded any different than the rest of the wing.
>
> Any comments or suggestions would be appreciated. Thanks.
>
As as buyer, I would not take any further look at such a ship without
poking to the glass on those cracks, to see if there are any
delaminations present. If there are, I would probably walk away, because
that means really a lot of work. If there are no delaminations present,
it is purely cosmetic, which will have influence on the price, but I
would still consider buying the ship.
As the seller I would agree that for inspection of the damage there has
to be some poking down to the glass where the cracks have formed.
If the seller agrees on that, and you are willing to invest some work
and/or money to get this fixed, take someone along who knows how to
judge the damage and the possible work that has to be invested for the
repair.
--
Peter Scholz
ASW24 JE
JJ Sinclair[_2_]
June 28th 12, 11:50 PM
I bet I have ground out a hundred cracks that look like these. None of them went into the glass. A few times I have found what looked like glass gracks, but after scrubbing it with ascetone and blowing it off I could see the fibers (with a magnifying glass) were not broken. Gelcoat cracks that formed as a result of structureal failures are seldom straight and look more like ZZ, not ll, like these. A tap-test should show if any delamination has occurred in the area around the cracks.
I'm just say'n,
JJ
aerodyne
June 29th 12, 02:40 AM
IMO, RAS is not the place to ask such a specific question. Review
the logbooks, and compare to 337's that the title search shows.
Contact the 337 originators and ask them the questions on the areas
they repaired. Most important, hire a competent repairman to do a
prepurchase inspection. Even if you paid for the repairman travel, it
would be a fraction of the price JJ has suggested for a possible
repair. If more people would do this, there would be more repairman
that would be less hungry and still affordable.
In short, treat this as a real aircraft purchase, because it is.
Check numerous on line buying guides, such as AOPA, and I think you
will find that this is a small portion of what is considered to be DD
on an aircraft purchase.
FWIW, I have seen a jagged crack I WAS SURE was structural damage,
only to find none, just the edge of an overlap splice. I have seen
fine hairline cracks at spoiler corners I was fairly sure was just the
gelcoat, only to find no glass under it, just wood putty. Also,
cracks in an area that taps good may have a deep dent/delam in a
sandwich laminate covered with filler, which may require structural
repair.
Aerodyne
Mike C
June 29th 12, 04:55 AM
On Jun 28, 7:40*pm, aerodyne > wrote:
> IMO, RAS is not the place to ask such *a specific question. *Review
> the logbooks, and compare to 337's that the title search shows.
> Contact the 337 originators and ask them the questions on the areas
> they repaired. Most important, hire a competent repairman to do a
> prepurchase inspection. *Even if you paid for the repairman travel, it
> would be a fraction of the price JJ has suggested for a possible
> repair. If more people would do this, there would be more repairman
> that would be less hungry and still affordable.
>
> In short, treat this as a real aircraft purchase, because it is.
> Check numerous on line buying guides, such as AOPA, and I think you
> will find that this is a small portion of what is considered to be DD
> on an aircraft purchase.
>
> FWIW, I have seen a jagged crack I WAS SURE was structural damage,
> only to find none, just the edge of an overlap splice. *I have seen
> fine hairline cracks at spoiler corners I was fairly sure was just the
> gelcoat, only to find no glass under it, just wood putty. *Also,
> cracks in an area that taps good may have a deep dent/delam in a
> sandwich laminate covered with filler, which may require structural
> repair.
>
> Aerodyne
RAS is a great place to ask such questions and get opinions, your
offered opinion being one. Data points.
On Wednesday, June 27, 2012 10:32:20 AM UTC-7, (unknown) wrote:
> I'm looking at a glass ship to possibly buy that is in pretty good condition. The Gel coat was last done in 94 or so and is very white with no crazing. The ship does have some cracks both on the bottom of the horizontal stab near the cutout for the attach post. It also has some near the trailing edge of the upper wing skins and also on the bottom wing skins. The cracks in the upper surfaces are centered in small depressions that almost look a well formed caulk line that was smoothed with a finger.(just a description of the shape not what I think was actually done) I'm guessing that someone in the past possibly tried to sand out some earlier cracking which later reappeared or possibly was filled with a filler that later shrunk. The cracks on the bottom of the wing are much longer cordwise but don't have the depressions like the ones on top.
>
> Here is a link to a picture of the bottom of the tailplane.
> http://www.flickr.com/photos/66126228@N08/7455559308/sizes/k/in/photostream/
>
> Here is a link to a picture of the top of the wing skins.
> http://www.flickr.com/photos/66126228@N08/7455558914/sizes/k/in/photostream/
>
> I know how hard it is to judge this kind of thing from pictures but can any of you that have repaired things like this in the past take a guess as to weather this would be a simple cosmetic repair or does it look like some glass work would be required. I tried tapping adjacent to all the cracks and didn't find any areas that sounded any different than the rest of the wing.
>
> Any comments or suggestions would be appreciated. Thanks.
I refinished my sailplane and sanded all the gel coat off, I hired a man of Mexican decent to do the fuse and he did an excellent job but my white boys could do nothing but complain about doing the wings so I left a little gel coat on in places in hopes of retaining the contour. But in the places I left the gel coat cracks are now starting to show. I will now have to go back and sand back through to the gel coat untill the cracks are gone then body work and paint. Do it right the first time. When sanding off the gel coat you have to be carefull not to go through the glass but if a crack does go into the glass sand the crack out and lay a few plys of glass back over the spot and sand back down. I do not believe that gel coat cracks can cause the structure to fail, it just looks bad.
Walt Connelly
June 30th 12, 07:53 PM
Well....you know what they say about us white boys. Can't run, can't jump.
Walt[/QUOTE]
Frank Whiteley
June 30th 12, 09:41 PM
On Wednesday, June 27, 2012 8:25:48 PM UTC-6, (unknown) wrote:
> It's a Kestrel. I realize that these will need to be repaired at some point if not right away and the negotiations would take that into account. That's why I'm looking for more informed opinions. By pretty good shape I was basically referring to the overall condition other than these cracks. The rest of the gel looks quite amazing considering the age and compared to some other ships I've inspected with much more recent finishes. The rest of the ship's gel is so good that it would be a real shame to have to refinish the enitre wings and tailplane just to fix these localized cracks. Yes there are cracks. All of the ones on the tail are pictured and there are maybe 6 or so on each wing. I'd just like to get a better idea of what kind of repairs I might be looking at if I were to purchase the ship. However as I mentioned it's very hard to tell in person without being able to dig deeper, let alone by looking at some pictures online. Thanks for the help.
There are Kestrels, and then there are Kestrel 19's. There was an odd 19 in Nevada I looked at nearly 30 years ago that had 'funny' tips that needed work. It didn't look like a Slingsby Kestrel 19, so I think someone added the tips to a 17. I passed on that one.
The forward attach on the horizontal appears to need some tidy work. Safety wire before flying through that hole in the front handle and the tab with the hole.
If it were two cracks, I might have though it was from a wing saddle. Six on each wing might indicate the glider was tied out, maybe with wing covers.. Is there a set with the glider? I've seen interesting cracks and crazing on surfaces on the 'sunny' sides of wings and horizontals in fiberglass topped trailers and from use of wing covers. Maybe there's a 'pattern' to the location of these cracks that matches the trailer structure (moisture drips) or cover seams. Kestrel wings are balsa/fiberglass sandwich skins. I'd probably thump around the cracks with a large coin to see if it buzzes, but these look like 'weathering' rather than structural.
Frank Whiteley
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