Schwabelack vs Polyurethane
Simon Waddell
winter. Polyurethane costs 35% more than schwabelack gel coat. Can anyone
tell me the advatages of the one over the other, and why it might be a good
idea to pay 35% more? The glider is based in Switzerland, so temperature
extremes aren't too extreme and my body won't cope with serious wave flying
any more so cold soaking is not too much of an issue. I'm not really
interested in discussing the pros and cons of giving an old lady a face
lift - that's too personal.
Al
Gelcoat is not well suited to glider wings hence all the refinishes that are
needed on 20 year old ships.
Al
"Simon Waddell" <si...@leswaddells.ch> wrote in message
news:3f088...@news.bluewin.ch...
Mike Borgelt
If it is truly Schwabelack and not Vorgelat then the gel coat finish
is OK if you don't fly in wave at very low temperatures and the gel
coat was applied in acordance with the manufacturers instructions.
Better still is the Australian gel coat made by Huntsman. Lots of good
experience with this over nearly 20 years.. Avoid vorgelat of any
type at any cost. Unfortunately this is still used by all, the major
glider manufacturers and is essentially useless. It makes nice
undercoat for PU when newish(before it cracks - and it *will* crack).
When customers form Oz talk to the Germans about this they get lots of
arm waving and a refusal to consider using the vastly superior Aussie
product. Not invented here I guess.
Mike Borgelt
Rod
36 degrees C. Tuesday it was 12 degrees C. I'd say that is pretty extreme;
especially for Switzerland.
My H301 still has about 70% of the original coat. Unfortunately, the
material is poisionous and as far as I know it is no longer available.
However, if you can get the old material, I'd suggest you avoid PU.
Rod
Simon Waddell
etc when you consider day/night temperatures.
The folk who will do the work told me that the good, old
Vorgelat/Schwaabbelack was carcinogenic and for some reason it was
banned.... The present composition is not carcinogenic, but is not as good
either. They also suggested that it would be good for at least 12-15 years,
whereas poly-u just keeps going; their view was that for a 25 year old
glider, Schwa.... should be good enough. However, since the glider has
clocked up less than 2000 hrs airtime in 25 years, and is lifed for 6000
(for the moment) it should be good for another 50 years of flying, so maybe
poly-u is the way to go, for when we both join the Oldtimers ....
I was also told that poly-u is applied over a base coat of Schwaabbelack; so
I have two unanswered questions:
1) What stops the base gel-coat cracking up and ruining the top coat of
poly-u?
2) What does all the paint do to the weight of the glider?
Time to call the workshop again, I think
"Rod" <roderi...@yahoo.com> wrote in message
news:3f09e87b$1...@news.swissonline.ch...
Basil Fairston
an old cracked vorgelat glider that had anti-collision paint applied from
new and remove it. Under one thin layer of orange cellulose the gel coat is
perfect.
2) PU coat is very thin. If you have removed a bit of gel coat to key the
surface you don't add much weight.
Mike Borgelt
wrote:
>
>
>My H301 still has about 70% of the original coat. Unfortunately, the
>material is poisionous and as far as I know it is no longer available.
Not quite On Topic but:
So is the lead in solder and our friends in the EU are about to get
rid of it. Like the gelcoat there is no really good substitute(in
Europe anyway - Aussie gelcoat works fine here and I don't think is
any more poisonous than what the sailplane factories are currently
using.) We can all look forward to less reliable electronics in the
future to save the 1% of lead in electronics going into people/"the
environment(TM)"(I always have old circuit boards with my wheaties and
milk) Note that 81% of lead is used in batteries and 5% in ammunition
and you see the urgent necessity to get the lead out of electronics.
Mike Borgelt
Benjamin Bauer
"Simon Waddell" <si...@leswaddells.ch> schrieb im Newsbeitrag
news:3f0a5...@news.bluewin.ch...
You have to pay attention! Vorgelat and Schwabbellack are different things!
Vorgelat is used by Schleicher. This paint is getting cracks after 5 years
(German conditions). Schwabbellack was used by DG since the DG300 (don´t
know before) and i have never seen a "yellow" or "cracked" DG in Germany.
Only for Carbonfibre planes its necessary to do PU or better Acrylic-Paint
specially for flying in very cold areas.
> The folk who will do the work told me that the good, old
> Vorgelat/Schwaabbelack was carcinogenic and for some reason it was
> banned.... The present composition is not carcinogenic, ....
in about 10 years, all of our actual Paints are poissonous.......
Greetings from Karlsruhe/Germany
Benjamin Bauer
Stewart Kissel
ing already in the gelcoat...why would you not use PU? Checking around w=
ith pilots that have recently refinished ships, gelcoat is still being us=
ed more the PU. I have been told that humidity is tough on PU, but that =
is not an issue out west. JJ feel free to jump in here if you are back =
from racing and lurking this thread.
Mark Navarre
cracking only where the coating is thick, and there is mechanical stretching,
ie: bottom of wings near roots, which is a typical ASW-20 problem anyway due to
the rubbery wings. There is no crazing anywhere, and the finish waxes and
polishes beautifully.
If you use gelcoat, this is the stuff.
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Mark Navarre
ASW-20 OD
California, USA
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