Poly paint

Yep!
They finally are.
So are Stemme and DG/LS
Paul


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

Mike Borgelt wrote in message . ..
On Tue, 28 Oct 2003 16:01:27 +0000, Robert Ehrlich
wrote:

Miguel Lavalle wrote:

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

"ruediger" wrote in message
om...
Mike Borgelt wrote in message
. ..
On Tue, 28 Oct 2003 16:01:27 +0000, Robert Ehrlich
wrote:

Miguel Lavalle wrote:

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

Mike Borgelt wrote:
...
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.

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

Mike Borgelt

On Wed, 29 Oct 2003 10:24:12 +0000, Robert Ehrlich
wrote:



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

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


"Mike Borgelt" wrote in message
...
On Wed, 29 Oct 2003 10:24:12 +0000, Robert Ehrlich
wrote:



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

With a PU finished glider, how do you deal with the spar cap shrinkage problem?

On 29 Oct 2003 22:47:59 -0800, (Liam Finley) wrote:

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

On Thu, 30 Oct 2003 16:05:37 +1300, "Paul"
wrote:


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