Question about Gelcoat

[Walt Connelly]

I see planes that are "refinished" in polyurethane. Is this different
from GelCoat? I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly. Is PU more durable than Gelcoat? Is one better than the
other? The glass vs aluminum thing has me leaning toward aluminum big
time. I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.

Walt

[Mark Jardini]

On Feb 11, 7:08 am, Walt Connelly <Walt.Connelly.

I see planes that are "refinished" in polyurethane.  Is this different
from GelCoat?  I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly.  Is PU more durable than Gelcoat?  Is one better than the
other?  The glass vs aluminum thing has me leaning toward aluminum big
time.  I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.
Walt
--
Walt Connelly

Walt

you could be very happy with an SGS 1-35. Nice bird and low
maintenance, rugged and fun to fly. Not expensive.

Mark

[Jim Beckman]

Post by Mark Jardini
you could be very happy with an SGS 1-35. Nice bird and low
maintenance, rugged and fun to fly. Not expensive.

There's a very nice looking example of the fixed-gear model for sale on
Wings & Wheels, page 2. If I didn't already have one, I'd be going to
take a look.

Jim Beckman

[Darryl Ramm]

On Feb 11, 7:08 am, Walt Connelly <Walt.Connelly.

I see planes that are "refinished" in polyurethane.  Is this different
from GelCoat?

Yes. Gelcoat is polyester. Polyurethane is well--polyurethane.

 I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly.

Or more. Have somebody who knows composites look at the glider and see
if stuff is just cosmetic and try to get a firm quote on a refinish
before you buy of you go that route.

 Is PU more durable than Gelcoat?  

Yes and especially more resistant to UV/sun damage. There is usually a
polyester layer between the epoxy/composite and the polyurethane
paint. - especially on a refinish -- where a lot depends on how well
most of the existing gelcoat has been removed before the PU paint is
applied.

A refinish might cost $20k or more but might be *worth* much less--it
depends on how well it was done.

Is one better than the
other?  

If properly done there is really little reason to argue for gel coat,
except that maybe the argument that it is easier to repair.

The glass vs aluminum thing has me leaning toward aluminum big
time.  I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.

Aluminum gliders can have their own issues, corrosion, fatigue, etc.
Ask a Blanik owner.

Walt
--
Walt Connelly

Darryl

[bildan]

On Feb 11, 8:08 am, Walt Connelly <Walt.Connelly.

I see planes that are "refinished" in polyurethane.  Is this different
from GelCoat?  I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly.  Is PU more durable than Gelcoat?  Is one better than the
other?  The glass vs aluminum thing has me leaning toward aluminum big
time.  I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.
Walt
--
Walt Connelly

Don't be too quick to dismiss glass - it will last as long if not
longer than metal. Take a look at a 1960's Labelle - some of them
still look nearly new. Too bad they don't still use the same gel coat
material.

Factory gelcoat can crack if not well cared for but cracks don't
necessarily mean the underlying structure is damaged in any way.
Clean, wax regularly & don't leave it tied out in the weather. PU is
a well known material which will outlast gelcoat but requires a little
more expertise to patch so it doesn't show.

The best advice is buy the glider with the best trailer.

[Herbert kilian]

Post by bildan
On Feb 11, 8:08 am, Walt Connelly <Walt.Connelly.

I see planes that are "refinished" in polyurethane.  Is this different
from GelCoat?  I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly.  Is PU more durable than Gelcoat?  Is one better than the
other?  The glass vs aluminum thing has me leaning toward aluminum big
time.  I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.
Walt
--
Walt Connelly

Don't be too quick to dismiss glass - it will last as long if not
longer than metal.  Take a look at a 1960's Labelle - some of them
still look nearly new.  Too bad they don't still use the same gel coat
material.
Factory gelcoat can crack if not well cared for but cracks don't
necessarily mean the underlying structure is damaged in any way.
Clean, wax regularly & don't leave it tied out in the weather.  PU is
a well known material which will outlast gelcoat but requires a little
more expertise to patch so it doesn't show.
The best advice is buy the glider with the best trailer.

Bill,
There's a number of German workers dying from cancer or already dead
from handling the Schwabbellack gel-coat that you refer to. The stuff
was toxic and it's good they discontinued it, good riddance.
Regarding trailers, the fiberglass shells are a case study in the very
limited life expectancy of the currently used coatings, they look
horrible after 10-15 years max unless kept indoors.

[Tim Mara]

read the below direct from Heir Webers (DG) website....Just happens I was
there as this conversation went on..
what I knew then was that Schwabbellack was no longer used and hadn't been
used for many years...it didn't seem to stop Mr. Weber from using this as
sales promo.regardless of how inaccurate it was...
tim


Schwabbellack" or "Vorgelat" - which one is "better"?
- there are differences even in the "standard finish".
At the SSA convention 2004 in Atlanta I had this interesting conversation:
Our new LS agent said to me: "Friedel, I see gliders from all over the
United States in my workshop for re-gelling. Some of the gliders really look
pretty awful with big cracks and yellow patches. I see gliders from
Rolladen-Schneider, .... gliders, lots of ..... gliders, but never a "DG".
Why is that?"

Wilhelm Dirks was also present and gave this simple explanation:
For several years now the other manufacturers have been using "T35-Vorgelat"
for spraying in the moulds. Only DG has always been using the so-called
"Schwabbellack".

The T35 offers significant production advantages to the manufacturer. You
can spray all moulds at once and leave them, and then carry on the next
morning. It is also possible to roll the resin into the dried gelcoat. With
Schwabbellack however you have to work using the wet-in-wet technique, which
is why one has to start working on it at 5am, spraying only one mould at a
time, finishing the complete mould and only two hours later carrying on with
the next one, and the next one, etc. This is of course a far more
complicated manufacturing process and also has cost implications.

HOWEVER: There's no way around it: Schwabbellack is better - both regarding
the look of new gliders as well as its durability. I don't think I'm
boasting when I say that DG is well-known everywhere for a very good finish.
And now you know why!

The staff in our external finish partner company FBS keep telling us that
customers, when having their gliders re-gelled, quite often only want one
specific finish - and that's a finish in "DG quality"!

Everybody knows what that is, and it says it all, doesn't it?

On Feb 11, 8:08 am, Walt Connelly <Walt.Connelly.

I see planes that are "refinished" in polyurethane. Is this different
from GelCoat? I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly. Is PU more durable than Gelcoat? Is one better than the
other? The glass vs aluminum thing has me leaning toward aluminum big
time. I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.
Walt
--
Walt Connelly

Don't be too quick to dismiss glass - it will last as long if not
longer than metal. Take a look at a 1960's Labelle - some of them
still look nearly new. Too bad they don't still use the same gel coat
material.
Factory gelcoat can crack if not well cared for but cracks don't
necessarily mean the underlying structure is damaged in any way.
Clean, wax regularly & don't leave it tied out in the weather. PU is
a well known material which will outlast gelcoat but requires a little
more expertise to patch so it doesn't show.
The best advice is buy the glider with the best trailer.

Bill,
There's a number of German workers dying from cancer or already dead
from handling the Schwabbellack gel-coat that you refer to. The stuff
was toxic and it's good they discontinued it, good riddance.
Regarding trailers, the fiberglass shells are a case study in the very
limited life expectancy of the currently used coatings, they look
horrible after 10-15 years max unless kept indoors.

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[Morgans]

Post by Herbert kilian
Bill,
There's a number of German workers dying from cancer or already dead
from handling the Schwabbellack gel-coat that you refer to. The stuff
was toxic and it's good they discontinued it, good riddance.
Regarding trailers, the fiberglass shells are a case study in the very
limited life expectancy of the currently used coatings, they look
horrible after 10-15 years max unless kept indoors.

So what is different about the gel coats used in most pleasure boats and
the non toxic airplane gel coats? I see boats that are kept out in the sun
nearly year round, and with a couple waxings per year and a polish out every
few years, they seem very durable and good looking.

[Andy]

Post by Herbert kilian
Bill,
There's a number of German workers dying from cancer or already dead
from handling the Schwabbellack gel-coat that you refer to.  The stuff
was toxic and it's good they discontinued it, good riddance.
Regarding trailers, the fiberglass shells are a case study in the very
limited life expectancy of the currently used coatings, they look
horrible after 10-15 years max unless kept indoors.

 So what is different about the gel coats used in most pleasure boats and
the non toxic airplane gel coats?  I see boats that are kept out in the sun
nearly year round, and with a couple waxings per year and a polish out every
few years, they seem very durable and good looking.
--
Jim in NC

When I asked what the finish was on my Cobra trailer I was told it was
marine gel coat. Those may not have been the exact words, I'd have to
hunt for the email, but no doubt the message was - same as used on
boats.

Andy

[Eric Greenwell]

Post by Walt Connelly
I see planes that are "refinished" in polyurethane. Is this different
from GelCoat? I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly. Is PU more durable than Gelcoat? Is one better than the
other? The glass vs aluminum thing has me leaning toward aluminum big
time. I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.

A LET 33 Solo might suit you just fine.

[Bob Whelan]

Post by Walt Connelly
I see planes that are "refinished" in polyurethane. Is this different
from GelCoat? I have looked at ships whose gelcoat is horrible and
understand that it can cost in excess of 20K dollars to refinish
properly. Is PU more durable than Gelcoat? Is one better than the
other? The glass vs aluminum thing has me leaning toward aluminum big
time. I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.

Walt,

At the risk of telling you stuff you already know, plastic gliders are
generally built 'from the outside in', & their smooth external finish
(assuming good gelcoat) comes from female molds into which gelcoat is
generally sprayed prior to the skin layers & epoxy going in. So THE
fundamental role of gelcoat is to ensure the weave of the outermost cloth
layer isn't visible when the cured structure is popped from the mold.

Another role of gelcoat is UV protection. (If sprayed gelcoat was not used,
something else would have to be.)

It's this latter which most (at least non-racer sort of) folks 'in the know'
probably worry about when loooking at a glider with cracked/chipped gelcoat,
though some undoubtedly obsess over 'lost L/D'. (As the late Dick Johnson used
to say: "Air has fingers, but no eyes.")

FWIW, you'll likely encounter a *lot* of 'FUD' (Fear. Uncertainty, Doubt.)
when it comes to gelcoat opinionating. I'd encourage you - regardless of what
sort of ship/structure you opt for in the near future - to continue the
process of self-education, and strongly suggest you relentlessly include the
'Why do you say that?' tool in your questioning kit. The answers will help you
distinguish between 'FUD-based' answers and genuine 'knowledge-based' ones.
(Most owners of any sort of glider have done this at some level prior to
purchasing - perhaps plastic owners more so simply because of the relentless
conservative streak often found in pilots. By 'conservative' I mean a general
reluctance to opt for anything perceived as 'out of mainstream thought.')

FWIW, I consider myself lucky in that my introduction to the sport was via a
superb engineer (who performed major aerodynamic and structural modifications
to fiberglass gliders) who approached plastic gliders from an engineering
perspective, and was willing to answer - or point me in the direction of
answers to - every question I threw at him. Since then (early 1970's), I've
seen a lot of people throw a lot of FUD-based money toward gliders that -
structurally speaking - didn't need it. I suppose one could rationalize that
it made them feel better, and in that sense it wasn't wasted money, but...

In any event, every structural material used in gliders has its own pros &
cons, and you've already heard of some via RAS. It's a start!

Regards,
Bob W.

[Jim Beckman]

Post by Walt Connelly
The glass vs aluminum thing has me leaning toward aluminum big
time. I don't ever expect to be competing seriously in cross country
competition so a bird for local fun might be adequate.

Hey, you can have a fun non-glass bird and still compete at the national
level. And it's dirt cheap. It's called a Schweizer 1-26. If you can
fly one of those things in competition against the likes of Ron Schwartz,
Bob von Helens, and some others, and finish well, you've got big-time
bragging rights. And you can paint it any way you want!

Jim Beckman