BoatBanter.com - View Single Post - 260 Defiance, not that dissimilar to a Parker

wrote:
Speaking of the difference, I've often wondered if they use different
resins in vacuum molds. In the roller method, the epoxies are fairly
stiff (usually due to the "induction" time in which the catalyst acts
on the resin), but it would seem to me to achieve proper penetration
of the glass in a vacuum system, the liquids would be fairly light.

Yes/No?

***************

I was invited to the 25th Anniversary celebration of a local
manufacturer, Nordic Tug.
They had a few hundred people in attendance, from all across the
country, and almost all were Nordic Tug owners. Impressive turnout
during one of our rare snowy days and in the middle of January, but it
was like the gathering of an enthusiastic clan. I digress....

Spam

Nordic had a number of vessels on display in all stages of build and
fitout. Nordic had set up a demonstration of vacuum bag, or infusion
molding, in the laminate shop. We observed the molding of a cabin top.

The gelcoated mold gets one layer of vinylester resin prior to the
layup. This is to prevent "shrinkage" which could spoil the exterior
appearance of the finished component.
The glass mat and coring materials are then laid in place. For the
cabintop, Nordic uses three different weights of mat in the layup and I
would need to dig out my notes to be specific as to how many ounces
each fabric is rated. Many of the superstructural components in a
Nordic are cored, and a combination of serrated balsa as well as
synthetic coring materials are used in the buildup. All coring material
is designed to allow resin to flow throughout the layer, vastly
reducing any liklihood of a future separation between the FRP and the
core.

All syn coring materials are closed cell, the resin is NOT intended to
"saturate" the core other than the outer surfaces where hopefully the
glass skins will be properly bonded.

There is a difference in the layup process when preparing for infusion
molding. There are certain materials included that promote the flow of
resin throughout the layup and the entire process is conducted with an
emphasis upon assuring a maximum, thorough wet out. It isn't just the
same layup one would use with roller laminating and then vaccum
infused.

It can't be the "same" because normal cloth & mat won't flow the resins
freely enough, the problem which you unwittingly admit is that uniform
wetout is an issue & excess resin in glass is almost as damaging the
finished laminate as not enough resin
..

Once the layup is completed, a plastic sheet (vacuum bag) is placed
over the mold and some plastic tubed "plumbing" installed to remove the
air from the bag and create a vacuum. When the vaccum has been
estabished, the technician uses an electronic sensing device to check
the perimeter and the central vacuum connections for any leaks. After
the integrity of the vaccum is assured, the infusion begins.

All very technical hey Chuck???? they suck a vacuum & turn the tap on:-)

Nordic uses vinylester resin. The technician explained to us that a
number of factors are considered when adding the catalyst to the resin,
including ambient temperature, of course.
The resin itself was heated to a controlled temperature, (about
70-degrees), and then the catalyst was added. It would be hard for me
to compare the density of the infusion method resin with what the
density might have been in a roller lamination- but I have no doubt
that the mixture was calculated to be optimal for infusion molding. A
valve was opened to allow the mixture to flow into the mold, and during
the minutes required for the dark colored resin to spread throughout
the mold the technician was constantly monitoring the flow and spread
of the liquid.

Care to tell us how???? You can only see the glass on the inside of the
core, how much resin is being spread through the glass behind the core
is not visible; yes??? so tell us exactly "how" the "technician"
monitored the wetout behind the core??? This is your story Chuckles so
tell us the answer, you were there after all:-)

The greater atmospheric pressure outside the bag helped press and
squeeze the resin into the mat.

This is marketing BS which I think you just made up now???:-)

Before the resin is allowed to flow there is a vacuum, the plastic
sheet liner has already pressed the laminate(s) & the core against the
mould with the best part of 14.7 psi, an enormous pressure in these
premises.

The issue is that various parts of the glass layup & even the core are
more rigid than others (overlaps etc) that means those parts create a
hard dam wall between the plastic sheet & the mould, that interferes
with the even flow of the resin, again what the risk is that the resin
will flow into the easy bits which will get too much resin (much weaker
than a proper proportion of resin) or other parts will miss out on a
full dose of resin (see above just as bad)

Nordic has been infusion molding cabin parts for some time now, and has
become so confident in the process that beginning in March or April
they will begin vacuum bagging their hulls as well.
When you put a ten year hull warranty on a million dollar boat (some of
the larger models are now well over the 7-figure mark), you want to be
sure the technology is first rate.

I'd suggest it saves them enough that the occasional hiccup can be
amortised into the system. Does the 10 year hull warranty include
against any blistering???

There are some potential advantages, in my opinion. For instance, the
assurance of a "wet" layup.

No such assurance it there indeed the real problem is some area(s) may
be too wet, which is a big no no.

I suspect that in many of the traditional
"hand laminate" processes there are gaps at lunch times, shift changes,
etc where an underlying layer of glass is allowed to cure just a bit
more than desirable before the next layer is applied....possible source
for future delam.

That can happen but usually only with amateurs, proper laminators all
use unwaxed resins in the actual layup process, so going to lunch etc
isn't an issue, however you are now reverting to the "Yeah yeah well
Optimaxes blow up to" OMC Ficht defense:-)

Hand laid is these days seen as a plus in marketing, gee you used it
yourself in the spam article:-) notwithstanding the boat doesn't have a
hand laid hull:-)

There is less opportunity for dirt, dust, etc to find its way into the
laminate and that can additionally help reduce the liklihood of
eventual blistering. The use of chopped strand to build up thickness is
inconsistent with vacuum bag molding.

I don't understand this last bit???? Chopped strand mat i.e. in mat
form is either powder bound or emulsion bound otherwise it's not mat
it's chopped strand i.e. chopper gun, with mat it takes time to dissolve
the binders so in the infusion method it's not used; what BS story did
they give you??? Just like they have difficulties with any sort of cloth
so they use multi axial "mats" which are not "bound" but held together
usually with a light knit, trouble is "buildup" management is spotty at
best.

Opinons from OZ not withstanding, there is no reason to assume that
infusion molding will always be done poorly and traditional roller
laminating always done well. I'd be happy with a well built boat
constructed through either process.

It's a system that requires full on technical quality control which the
makers of $1mil. boats probably have, at least hope they have;-),
whereas a 23ftr???? who doesn't even want you to mention it's been used
in your spam???? which you of course comply with. Hmmm curiouser &
curiouser said Alice

K

This idiot has manufactured a story about his father being the biggest
OMC dealer on the NE coast of the US, needless to say Krause then says
that's where he learned all he obviously doesn't know about boats:-)

Here's just one of the lies from the "father" series, try to remember
he's talking $3000000 in 70s!! Honestly it's embarrassing that a grown
man would lie like this I guess that's the standard of union thugs ???

I sold off nearly $3,000,000 in new motors and boats, depressing
the new boat
industry in southern Connecticut for an entire season. Everything
was sold...every cotter pin, every quart of oil, 30 days after I started.
For near full-retail, too.