Discussion:
Poly paint
(too old to reply)
Miguel Lavalle
2003-10-28 01:06:26 UTC
Permalink
I am considering buying a second hand glider that was recently =
refinished
with poly paint as opposed to gel coat. What is poly paint? What are the
pros and cons of poly paint compared to gel coat?

Regards

Miguel
BTIZ
2003-10-28 01:09:20 UTC
Permalink
as long as the surface below was properly prepared.. should be ok.. that is
the standard for replacing old gel coats.. sand it down.. re profile the
wing.. and paint it..

BT
Post by Miguel Lavalle
I am considering buying a second hand glider that was recently =
refinished
with poly paint as opposed to gel coat. What is poly paint? What are the
pros and cons of poly paint compared to gel coat?
Regards
Miguel
unknown
2003-10-28 09:31:41 UTC
Permalink
I think that Miguel was asking the difference between gel coat and
poliurethane paint.
Anyway I don't have enough knowledge about the matter to explain it!
Post by BTIZ
as long as the surface below was properly prepared.. should be ok.. that is
the standard for replacing old gel coats.. sand it down.. re profile the
wing.. and paint it..
BT
Post by Miguel Lavalle
I am considering buying a second hand glider that was recently =
refinished
with poly paint as opposed to gel coat. What is poly paint? What are the
pros and cons of poly paint compared to gel coat?
Regards
Miguel
Steve H
2003-10-28 13:28:29 UTC
Permalink
Hi Miguel,
I used to own a Sportvega which was finished in a polyurethane paint. As
I understand the explanations at the time, the polyurethane finish is
softer, more elastic and cheaper to re-do. At around that time the BGA
DG 500 went to some astronomical height above Aboyne, in Scotland. I was
told that the extremes of temperature to which it was exposed and,
possibly, the rapidity of temperature change on ascent and descent,
resulted in extensive gel coat cracking; and that the polyurethane
finish on my rather ancient Sportvega would not have been similarly
affected. Lastly, if you do the prep work, a reasonable garage could
respray the glider for you at much less expense than the usual aviation
prices.
Steve

-----Original Message-----
From: Glider Pilot Network [mailto:***@gliderpilot.net]
Sent: Tuesday, October 28, 2003 9:46 AM
To: Steve H
Subject: [r.a.s] Re: Poly paint


------------------------------------------------------------
Newsgroup: rec.aviation.soaring
Subject: Re: Poly paint
Author: Jose M. Alvarez <>
Date/Time: 09:40 28 October 2003
------------------------------------------------------------
I think that Miguel was asking the difference between gel coat and
poliurethane paint. Anyway I don't have enough knowledge about the
matter to explain it!
Post by BTIZ
as long as the surface below was properly prepared.. should be ok..
that
is
Post by BTIZ
the standard for replacing old gel coats.. sand it down.. re profile
the
Post by BTIZ
wing.. and paint it..
BT
"Miguel Lavalle" wrote in
Post by Miguel Lavalle
I am considering buying a second hand glider that was recently =
refinished with poly paint as opposed to gel coat. What is poly
paint? What are
the
Post by BTIZ
Post by Miguel Lavalle
pros and cons of poly paint compared to gel coat?
Regards
Miguel
------------------------------------------------------------
JJ Sinclair
2003-10-28 14:54:54 UTC
Permalink
Post by Miguel Lavalle
What is poly paint? What are the
pros and cons of poly paint compared to gel coat?
Hi Miguel,
There are two "Poly" paints used on sailplanes, Polyeurathane and Acrylic
Urathane. I just repainted my Genesis 2 with Acrylic Urathane and found it very
easy to work with. Preped the non-damaged areas by contouring with 60 grit,
followed by 220 and then paint with 3 medium coats. Wet sandad with 600wet and
800wet, then wool buffer and liquid rubbing compound.
The Genesis 2 and LAK -17 are painted with Acrylic Urathane by the
manufacturer. The only down-side that I am aware of, is the softer paint
(urathane) may blister more quickly, if left too long in a wet trailer
JJ Sinclair
Marc Ramsey
2003-10-28 16:52:36 UTC
Permalink
Post by JJ Sinclair
The Genesis 2 and LAK -17 are painted with Acrylic Urathane by the
manufacturer. The only down-side that I am aware of, is the softer paint
(urathane) may blister more quickly, if left too long in a wet trailer
JJ Sinclair
Actually the choice of paint is an option (at least on the LAK-17).
Ours is painted in painted with polyurethane. For $400 more we could
have had it painted in acrylic urethane, but we couldn't find anyone who
would say flat out it was worth the extra money. They also give you the
option of the ugly (but apparently bulletproof) epoxy paint that was
standard on the earlier LAKs...

Marc
JJ Sinclair
2003-10-28 19:02:01 UTC
Permalink
Post by Marc Ramsey
They also give you the
option of the ugly (but apparently bulletproof) epoxy paint that was
I would stay away from the epoxy paint because it yellows very rapidly and one
ends up with a ship the color of urine.

BTW, I have the color of the Acrylic Urathane used on the Genesis 2. It is;
Toyota 040/HP


JJ Sinclair
Robert Ehrlich
2003-10-28 16:01:27 UTC
Permalink
Post by Miguel Lavalle
I am considering buying a second hand glider that was recently =
refinished
with poly paint as opposed to gel coat. What is poly paint? What are the
pros and cons of poly paint compared to gel coat?
Regards
Miguel
All gliders in my club have gel coat, but our tow plane, a Super Dimona,
has a polyurethane paint. Some of the gliders have been refinished here
in our workshop, and the quality of this finish is far better than the
polyurethane of the Super Dimona. But this quality is probably also
better than the quality of a brand new glider. A few years ago, one of
our member who had learnt the skills for doing that kind of finish was
able to convince Schemp-Hirth to sell to him a new Ventus 2c unfinished,
arguing that he would be able to do the finish better than in the
factory, and he did it. If I understand it correctly, the main difference
between paint and geal coat concerning the quality of the finish is that
with paint it results mainly from work done before the painting and
with gel coat from work done after spreading the gel coat. Small corrections
are possible with the gel coat, I remember the owner of the Ventus 2c
adding some droplets of gel coat here and there during the process
before sanding again. Small defects become much more obvious when the
surface comes near to its final state. In a similar way, minor scratches
are easy to repair on gel coat by puting droplets of gel coat and
sanding. I don't know for paint. Also I have seen broken tails repaired
and re-gelcoated around the break with nothing remaining visible from the
break after that. Again I don't know for paint.
Mike Borgelt
2003-10-28 22:20:16 UTC
Permalink
On Tue, 28 Oct 2003 16:01:27 +0000, Robert Ehrlich
Post by Robert Ehrlich
Post by Miguel Lavalle
I am considering buying a second hand glider that was recently =
refinished
with poly paint as opposed to gel coat. What is poly paint? What are the
pros and cons of poly paint compared to gel coat?
Regards
Miguel
All gliders in my club have gel coat, but our tow plane, a Super Dimona,
has a polyurethane paint. Some of the gliders have been refinished here
in our workshop, and the quality of this finish is far better than the
polyurethane of the Super Dimona. But this quality is probably also
better than the quality of a brand new glider. A few years ago, one of
our member who had learnt the skills for doing that kind of finish was
able to convince Schemp-Hirth to sell to him a new Ventus 2c unfinished,
arguing that he would be able to do the finish better than in the
factory, and he did it. If I understand it correctly, the main difference
between paint and geal coat concerning the quality of the finish is that
with paint it results mainly from work done before the painting and
with gel coat from work done after spreading the gel coat. Small corrections
are possible with the gel coat, I remember the owner of the Ventus 2c
adding some droplets of gel coat here and there during the process
before sanding again. Small defects become much more obvious when the
surface comes near to its final state. In a similar way, minor scratches
are easy to repair on gel coat by puting droplets of gel coat and
sanding. I don't know for paint. Also I have seen broken tails repaired
and re-gelcoated around the break with nothing remaining visible from the
break after that. Again I don't know for paint.
The words "quality" and "gel coat"(as used currently by most of the
German glider manufacturers) should not be used in the same article.

The currently used gel coat will last a few years before cracking and
causing a very expensive refinish.

Polyurethane won't crack. Take a look at an old Pik20 or Std Jantar.

The scandal is that the cracking of the gel coat has been known since
about 1977(only a couple of years after they went to that product) and
the manufacturers flat out refuse to do anything about it.

Yes there are gel coat products that won't crack but as they "weren't
invented here" the manufacturers don't want to know.

A few people around here got Ventus 2's unfinished and had them
painted here with polyurethane.

Mike Borgelt
ruediger
2003-10-29 07:14:01 UTC
Permalink
Post by Mike Borgelt
On Tue, 28 Oct 2003 16:01:27 +0000, Robert Ehrlich
Post by Robert Ehrlich
Post by Miguel Lavalle
I am considering buying a second hand glider that was recently =
refinished
with poly paint as opposed to gel coat. What is poly paint? What are the
pros and cons of poly paint compared to gel coat?
Regards
Miguel
All gliders in my club have gel coat, but our tow plane, a Super Dimona,
has a polyurethane paint. Some of the gliders have been refinished here
in our workshop, and the quality of this finish is far better than the
polyurethane of the Super Dimona. But this quality is probably also
better than the quality of a brand new glider. A few years ago, one of
our member who had learnt the skills for doing that kind of finish was
able to convince Schemp-Hirth to sell to him a new Ventus 2c unfinished,
arguing that he would be able to do the finish better than in the
factory, and he did it. If I understand it correctly, the main difference
between paint and geal coat concerning the quality of the finish is that
with paint it results mainly from work done before the painting and
with gel coat from work done after spreading the gel coat. Small corrections
are possible with the gel coat, I remember the owner of the Ventus 2c
adding some droplets of gel coat here and there during the process
before sanding again. Small defects become much more obvious when the
surface comes near to its final state. In a similar way, minor scratches
are easy to repair on gel coat by puting droplets of gel coat and
sanding. I don't know for paint. Also I have seen broken tails repaired
and re-gelcoated around the break with nothing remaining visible from the
break after that. Again I don't know for paint.
The words "quality" and "gel coat"(as used currently by most of the
German glider manufacturers) should not be used in the same article.
The currently used gel coat will last a few years before cracking and
causing a very expensive refinish.
Polyurethane won't crack. Take a look at an old Pik20 or Std Jantar.
The scandal is that the cracking of the gel coat has been known since
about 1977(only a couple of years after they went to that product) and
the manufacturers flat out refuse to do anything about it.
Yes there are gel coat products that won't crack but as they "weren't
invented here" the manufacturers don't want to know.
A few people around here got Ventus 2's unfinished and had them
painted here with polyurethane.
Mike Borgelt
What gel coat product did GROB use? The finish is poor but all the
Astir's usually have no cracks. There are very few refinished Astirs.
Thank
Ruediger
F.L. Whiteley
2003-10-29 07:50:03 UTC
Permalink
Post by ruediger
Post by Mike Borgelt
On Tue, 28 Oct 2003 16:01:27 +0000, Robert Ehrlich
Post by Robert Ehrlich
Post by Miguel Lavalle
I am considering buying a second hand glider that was recently =
refinished
with poly paint as opposed to gel coat. What is poly paint? What are the
pros and cons of poly paint compared to gel coat?
Regards
Miguel
All gliders in my club have gel coat, but our tow plane, a Super Dimona,
has a polyurethane paint. Some of the gliders have been refinished here
in our workshop, and the quality of this finish is far better than the
polyurethane of the Super Dimona. But this quality is probably also
better than the quality of a brand new glider. A few years ago, one of
our member who had learnt the skills for doing that kind of finish was
able to convince Schemp-Hirth to sell to him a new Ventus 2c unfinished,
arguing that he would be able to do the finish better than in the
factory, and he did it. If I understand it correctly, the main difference
between paint and geal coat concerning the quality of the finish is that
with paint it results mainly from work done before the painting and
with gel coat from work done after spreading the gel coat. Small corrections
are possible with the gel coat, I remember the owner of the Ventus 2c
adding some droplets of gel coat here and there during the process
before sanding again. Small defects become much more obvious when the
surface comes near to its final state. In a similar way, minor scratches
are easy to repair on gel coat by puting droplets of gel coat and
sanding. I don't know for paint. Also I have seen broken tails repaired
and re-gelcoated around the break with nothing remaining visible from the
break after that. Again I don't know for paint.
The words "quality" and "gel coat"(as used currently by most of the
German glider manufacturers) should not be used in the same article.
The currently used gel coat will last a few years before cracking and
causing a very expensive refinish.
Polyurethane won't crack. Take a look at an old Pik20 or Std Jantar.
The scandal is that the cracking of the gel coat has been known since
about 1977(only a couple of years after they went to that product) and
the manufacturers flat out refuse to do anything about it.
Yes there are gel coat products that won't crack but as they "weren't
invented here" the manufacturers don't want to know.
A few people around here got Ventus 2's unfinished and had them
painted here with polyurethane.
Mike Borgelt
What gel coat product did GROB use? The finish is poor but all the
Astir's usually have no cracks. There are very few refinished Astirs.
Thank
Ruediger
All of the Twins from Grob, Twin Astir's and Twin II's, I've seen have
developed cracking on the leading edge of the wing at some point. This is
due to the gel coat being applied post wing assembly. That from the molds
seems robust.

Frank Whiteley
Robert Ehrlich
2003-10-29 10:24:12 UTC
Permalink
Post by Mike Borgelt
...
The words "quality" and "gel coat"(as used currently by most of the
German glider manufacturers) should not be used in the same article.
The currently used gel coat will last a few years before cracking and
causing a very expensive refinish.
Polyurethane won't crack. Take a look at an old Pik20 or Std Jantar.
The scandal is that the cracking of the gel coat has been known since
about 1977(only a couple of years after they went to that product) and
the manufacturers flat out refuse to do anything about it.
Yes there are gel coat products that won't crack but as they "weren't
invented here" the manufacturers don't want to know.
This is not true of all manufacturers. DG and Centrair use a very
good quality of gel coat, at least on the latest gliders (Pegase
90) for Centrair. My clubs owns 2 Pegases 90, they are 8 and 9 years
old and look like new. We also sold a DG 300 in order to replace
it by a more recent glider, I think it was more than 10 years old
and had no cracks. OTOH the policiy of the club is to buy used
gliders with badly cracked gel coat and so lower price, and to
use the local skill and available time to refinish them. So I
have seen badly cracked LS1f's and LS4's.
Post by Mike Borgelt
A few people around here got Ventus 2's unfinished and had them
painted here with polyurethane.
Mike Borgelt
Mike Borgelt
2003-10-29 21:48:37 UTC
Permalink
On Wed, 29 Oct 2003 10:24:12 +0000, Robert Ehrlich
Post by Robert Ehrlich
This is not true of all manufacturers. DG and Centrair use a very
good quality of gel coat, at least on the latest gliders (Pegase
90) for Centrair. My clubs owns 2 Pegases 90, they are 8 and 9 years
old and look like new. We also sold a DG 300 in order to replace
it by a more recent glider, I think it was more than 10 years old
and had no cracks. OTOH the policiy of the club is to buy used
gliders with badly cracked gel coat and so lower price, and to
use the local skill and available time to refinish them. So I
have seen badly cracked LS1f's and LS4's.
Robert,

That was my point. There are good quality gel coats available but some
manufacturers refuse to use them and this has gone on for 25 years.

Anybody know what product DG are currently using. I've seen that it is
Vorgelat T35 in which case my friends in the glider repair/refinish
business tell me you *will* have a problem.

Mike Borgelt
Paul
2003-10-30 03:05:37 UTC
Permalink
Our DG 1000s maintenance manual lists Lesonal UP Schwabbellack 0369066
or the MGS T35.
The glider is made with the lesonal.
The T35 can be used for repairs if needed.
Paul
Post by Mike Borgelt
On Wed, 29 Oct 2003 10:24:12 +0000, Robert Ehrlich
Post by Robert Ehrlich
This is not true of all manufacturers. DG and Centrair use a very
good quality of gel coat, at least on the latest gliders (Pegase
90) for Centrair. My clubs owns 2 Pegases 90, they are 8 and 9 years
old and look like new. We also sold a DG 300 in order to replace
it by a more recent glider, I think it was more than 10 years old
and had no cracks. OTOH the policiy of the club is to buy used
gliders with badly cracked gel coat and so lower price, and to
use the local skill and available time to refinish them. So I
have seen badly cracked LS1f's and LS4's.
Robert,
That was my point. There are good quality gel coats available but some
manufacturers refuse to use them and this has gone on for 25 years.
Anybody know what product DG are currently using. I've seen that it is
Vorgelat T35 in which case my friends in the glider repair/refinish
business tell me you *will* have a problem.
Mike Borgelt
Mike Borgelt
2003-10-30 20:55:19 UTC
Permalink
On Thu, 30 Oct 2003 16:05:37 +1300, "Paul"
Post by Paul
Our DG 1000s maintenance manual lists Lesonal UP Schwabbellack 0369066
or the MGS T35.
The glider is made with the lesonal.
The T35 can be used for repairs if needed.
Paul
Schwabbellack is the good gel coat. The current formulation does get
brittle at low temperatures and I believe there have been some
mechanical cracking failures after exposure. This is different
cracking from the Vorgelat cracking but sadly the same amount of work
to fix.

Mike Borgelt

John Galloway
2003-10-28 22:19:54 UTC
Permalink
Post by Mike Borgelt
A few people around here got Ventus 2's unfinished
and had them
painted here with polyurethane.
Mike Borgelt
If it were now they would have been able to get them
finished in PU by the factory.

John Galloway
Mike Borgelt
2003-10-29 01:49:54 UTC
Permalink
On 28 Oct 2003 22:19:54 GMT, John Galloway
Post by John Galloway
Post by Mike Borgelt
A few people around here got Ventus 2's unfinished
and had them
painted here with polyurethane.
Mike Borgelt
If it were now they would have been able to get them
finished in PU by the factory.
John Galloway
Schempp's are offering that now???

Mike
Paul
2003-10-29 03:48:25 UTC
Permalink
Yep!
They finally are.
So are Stemme and DG/LS
Paul
Post by Mike Borgelt
Post by John Galloway
If it were now they would have been able to get them
finished in PU by the factory.
John Galloway
Schempp's are offering that now???
Mike
Liam Finley
2003-10-30 06:47:59 UTC
Permalink
With a PU finished glider, how do you deal with the spar cap shrinkage problem?
Mike Borgelt
2003-10-30 20:51:42 UTC
Permalink
Post by Liam Finley
With a PU finished glider, how do you deal with the spar cap shrinkage problem?
You sand it and paint it again.

Around here the glider buyers are getting the wings in gel coat,
flying for a season or so, sanding and painting in PU.

Mike Borgelt
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