1. Composite materials Processing
Getting the process right
Alex Whatley
Marine Innovation Service Manager
Falmouth Marine School

2. Overview
• Falmouth Marine School
• The Marine Innovation Service
• The push to move to closed mould processes
• Implications of changing processes
• Summary

3. • Dedicated marine specialist campus of
Cornwall College, covering
boatbuilding, marine engineering, marine
science and leisure & water sports
• Courses from NVQ to Degree level (validated
by University of Plymouth)
• Full time courses, apprenticeships and
employer responsive programs
• www.falmouthmarineschool.ac.uk

4. • Technical Consultancy Service – not training
• Knowledge Transfer /Knowledge Exchange
• Marine specialism
• Strong composite materials focus
• Other technologies covered
• Service currently underwritten by ERDF

5. Composite materials – an overview
• 2 or more materials combined to make hybrid material;
Reinforced concrete, plywood, cob...
• Marine industry use fibre reinforced composites (FRP)
• Reinforcements (fibres), consolidated in a matrix
system (resin)
• Fibres most commonly glass, but also aramid
(Kevlar), carbon or natural (e.g. flax, jute or hemp)
• Resins most commonly polyester, but also
vinlyester, epoxy or bio resins (e.g. linseed oil derived)
• Cores used to increase bending stiffness – can be
wood, foam, paper/metal honeycombs

6. Composite processing - basic
• Resin is dispensed into a bucket
• Catalyst measured, added and mixed
• Resin applied to fibres in the mould using a brush
or foam roller
• Resin and fibres consolidated using metal paddle
roller or plastic squeegee
• MESSY AND SMELLY! Polyester resin gives off
styrene gas, which is a suspected carcinogen
• Lowest quality processing method – inconsistent
weight and mechanical properties

8. Composite processing - intermediate
• Use of vacuum to get better consolidation
over hand rolling; pressure approx 10 tons/m2
• Resin infusion uses this pressure to push resin
through dry laminate stack
• Fibres are laid dry into mould – better control
of fibre orientation
• Mechanical mixing and dispensing of resin and
catalyst further increases quality and reduces
waste (= monetary and environmental cost)

9. Composite processing – high tech
• Pre-pregs – fibre is pre-impregnated with
catalysed resin and then deep frozen to pause
chemical reaction
• Resin film infusion – plies of fibres are
interspersed with films of resin and then deep
frozen to pause chemical reaction
• Both require processing under a vacuum bag at
elevated temperature to reactivate resin curing
process
• High material and capital cost, but optimal weight
and mechanical performance

10. Why change?
• Higher quality product:
• Greater repeatability of weight and mechanical
properties in each moulding
• Opportunity to optimise structure – reduction of
weight for same or better strength and stiffness
• Easier to mould complex shapes and structures
• Higher tech design and build process allows innovation
• Potentially quicker processing times, needed for
business expansion or more economic production
• Better working environment – lower styrene emissions

11. Processing options – large structures
• In 2007, the National Composites Network
funded a feasibility study/cost comparison of
material choice and processing methods for
Rustler Yachts Ltd in Falmouth and the lessons
learnt were applied to the new R33
• The report looked at the following build
programs:
– Wet lay/vacuum consolidation
– Resin infusion
– Resin film infusion
– Pre-impregnated fabrics

12. Study outputs
• Pre-pregs were discounted on grounds of cost –
both materials and processing (oven)
• Wet lay/vacuum consolidation does not give
significant enough differences in working
conditions from the existing processes to be
considered
• This leaves resin infusion and resin film
infusion, including the SP Sprint system
• A cost and weight comparison was carried
out, based on the specific boat (a yet to be
developed 37ft model)

14. • Current wet lay/hand consolidation • Wet lay-up
• Low material cost, high labour cost per unit • Nett Weight of composite structure 8,231kg
• High structural weight • Projected Weight inc 10% margin 9,055kg
• Cost of composite Materials £25,036
• Projected cost including margin £27,539
• Labour (GBP) 535hrs @ £30/hr £16,050
• £68,625
• Cost/weight = 100%
•
• Resin Infusion • Resin infusion
• Higher material cost, lower labour cost per unit • Nett Weight of composite structure 4,620kg
• Lower structural weight - 56.1% of current lay-up • Projected Weight inc 10% margin 5,082kg
• Cost of composite Materials £35,517
• Projected cost including margin £39,069
• Labour (GBP) 400hrs @ £30/hr £12,000
• £86,586
• Cost/weight = 126%
•
• Resin Film Infusion • Resin film infusion
• Much higher material cost than resin infusion and no • Nett Weight of composite structure 4 098kg
reduction in labour cost • Projected Weight inc 10% margin 4,508kg
• Lowest structural weight - 49.8% of current lay-up • Cost of composite Materials £41,570
• Projected cost including margin £45,727
• Labour (GBP) 400hrs @ £30/hr £12,000
• Amortized oven cost £2,000
• £101,297
• Cost/weight = 148%

15. Who changes?
• Not a high end, expensive process
• Applicable in a range of projects
• Rustler Yachts – new 33ft model
• J Boats Inc – whole range, built in USA/France
• Cornish Crabbers have developed a 12ft
dinghy which was designed from the outset to
be built in resin infusion - desire to move all
models to infusion over the next 5 years

22. Scalable process
• Princess Yachts in Plymouth are infusing hulls
up to 40m in a single process – 6 tonnes of
resin in one shot!

24. Processing options – Smaller units
• Resin Transfer Moulding (RTM) and Vacuum RTM (RTM
light) allows double sided moulding to be produced in
‘one hit’
• Ideal where customer sees both sides of the product –
would otherwise be built in 2 parts and bonded
together
• True closed mould process – two solid moulds with
engineered cavity between them into which fibre is
loaded
• RTM uses mechanical clamping, VRTM uses vacuum as
primary clamping force
• Resin injected into cavity

25. Hurdles/changes/implications
• Capital investment
– Mould design to accommodate vacuum system
– Vacuum pumps and monitoring equipment
• Consumables cost
– Vac bags, sealing tape, pipe work etc
• ‘Clean space’ on shop floor amongst other
ongoing projects
• Staff development
• Getting the details right

26. The learning curve
• Understanding key processing principles is one
thing, but practical application is another!
• Small section trials and practice runs
• Help and support is available
– Marine Innovation Service
– National Composites Centre (Bristol)
– Supply chain e.g. equipment specialists Composite
Integration Ltd, material supply companies etc…
– Specialist training courses such as Composite Skills
Alliance to develop shop floor staff

27. Video Showcase
FMS dinghy build

28. Summary
• Driver to change processing method has to come
from a sound business plan
• Choice of processing has to be relevant to the
end product
• You don’t need to make sweeping changes...
incremental introduction of process change
allows analysis of impact
• Bolting on higher technology can work, but new
projects with technology built in from day one
give greater flexibility

29. Summary
• Of all the closed mould processes for large
structures, resin infusion offers the lowest
financial outlay for laminate quality and working
environment improvement
• However – developments of low temperature
pre-pregs continue to bring these materials
within reach of the most basic ovens (500C)
• The learning curve is steep – don’t try and
reinvent the wheel as there is plenty of help out
there, from other businesses to the supply chain

30. Alex Whatley
Marine Innovation Service Manager
alex.whatley@cornwall.ac.uk
07771907266
www.marineinnovationservice.co.uk
Next event:
Wednesday 13th February 2013
Composite Workshop, Ponsharden