Vacuum bagging clamps everything and draws out air bubbles, gives a more
consistent result with less resin. Resin infusion is vacuum bagging on
steroids, you pull a vacuum and you inject resin at pre-set points, the
resin is drawn in with great control - so even less material, better
results. Vacuum bagging can be done by an amateur, I have done it a few
times, whereas resin infusion is the domain of the pro.
Ideally you want enough resin to bond the layers together but just that
amount.
Graham Collins
Secret Plans
C&C 35-III #11
On 2014-03-01 9:19 PM, j...@svpaws.net wrote:
So vacuum bagging essentially draws the resin into the substrate as
opposed to just letting it sink in? I could see how that would be
more precise and require less resin. On that note, resin adds minimal
strength but bonds ?
All questions.
John
Sent from my iPad
On Mar 1, 2014, at 3:25 PM, Chuck S <cscheaf...@comcast.net
<mailto:cscheaf...@comcast.net>> wrote:
You sound on track, though you should start with a solid fiberglass
hull like the 1961 Alberg 35. Surprised the spec shows only 12600#
displacement.
Checking the brochure info, the 1990 34+ used "biaxial
fiberglass/kevlar hybrid laminate with (waterproof) Hydrex isothalic
NGP resin w aircraft quality balsa core. The deck is similar adding
coremat in winch areas.
At some time "vacuum bagging" reduced the amount of excess resin in
the whole build process and that was the heaviest element. Before
that, engineers were guessing at the total weight. Now it is more
exact.
My understanding of Kevlar is that it is stronger but still flexes.
A buddy of mine made a wakeboard of Kevlar and it would flex more
than fiberglass, and he could smack it with a hammer and just bounced
off. Carbon is much more expensive, not as strong as Kevlar, but
much, much, lighter and stiffer. Early carbon would shatter and
splinter when stressed. They improved the formula somehow and
re-enforce stress areas more so it is less brittle than before. They
put carbon in sails now.
Chuck
Resolute
1990 C&C 34R
Atlantic City, NJ
------------------------------------------------------------------------
*From: *j...@svpaws.net <mailto:j...@svpaws.net>
*To: *cnc-list@cnc-list.com <mailto:cnc-list@cnc-list.com>
*Sent: *Saturday, March 1, 2014 2:27:15 PM
*Subject: *Stus-List Help understanding composites
I'm but an accountant not an engineer. Help me understand this stuff..
So if I use a 1990 34+ as the baseline, the hull was a composite of
vinyl resin, presumably glass matt and chopped strand, balsa core and
Kevlar.
Now fast forward to 2000 and my early 121. The glass Matt has been
replaced by E glass, balsa has been replaced by core cell, glass
strand remains to add bulk and the Kevlar remains. Presumably this
provides a lighter hull as the e glass is stronger than matt, core
cell is lighter than balsa and requires less resin and the Kevlar
remains the same.
Fast forward another 10 years and we have epoxy, reinforced with
carbon which does the job of Kevlar, matt, e glass and strand. The
core cell remains.
Am I even close?
John
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