Crestamould
T27
Polyester-based sprayable and machinable
tooling compound
Product Overview
Crestamould
T27 is a sprayable modified polyester compound designed for milling of large plugs (10-
25 m, 30-75 ft, ) or direct limited production moulds with Computer Numerical Control (CNC) multiple
axis machines. This material combines unique qualities, can be sprayed with few passes up to a thickness
of approx. 25mm (1 ). Crestamould
T27 provides a homogenous substrate that prevents print from
the underlying structure, and gives sufficient flexibility to prevent cracks. Crestamould
T27 retains its
machinability over time – it is as easy to machine after 6 months as when freshly sprayed. Crestamould
T27 is available as a R (Regular) and S (Summer) version. Moulds using Crestamould
Tooling Resin RTR
4010PA are successfully produced with Crestamould
T27 plugs.
Features and Benefits
Fast application, build-up with few passes
Tough and resilient, remains non-brittle
Maintains dimensional tolerance over time
Low shrinkage, low exother
Easy to cut and machine with carbide tools
Machines/ shaves like wood – no dust generation
Low tool wear
Remarkable profile of finished parts
No settling in the equipment
Easy to repair – bonds to itself
Compatible with poly/ vinylester sanding primers
Constant hardness over time, after 24 hours, or
after 6 months
www.scottbader.com Crestamould
T27 | Page 1 of 3 | Version: February 2019
General Properties
Colour Pink
Density 1.04 – 1.10 g/cc; 8.6 – 9.2 lbs gallon
Viscosity, Brookfield HAF T-C, @ 5rpm, 24
o
C 196,000 – 216,000 cps
Thixotropic Index 5-7
Peak Exotherm, 100 gram mass 132 C (270 F)
Hardness after 24 Hours, 24
o
C (75
o
F) Minimum 55 Shore D
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Process Temperature
The ideal shop temperature is 25
o
C (77
o
F). The useable range for Crestamould
T27 R (Regular) is from
21
o
C (70
o
F) to 29
o
C (85
o
F); for Crestamould
T27 S (Summer) it is from 24
o
C (75
o
F) to 35
o
C (95
o
F).
Maintain catalyst levels between 1.25 and 1.8% by volume. Below 21
o
C (70
o
F) obtaining a spray pattern will
be difficult.
Catalyst Types
Catalyst used for internal ATC QC is Arkema Luperox DDM-9. An equivalent catalyst is Luperox K1.
Catalysts in the same category are Syrgis Norox MEKP-9; Syrgis Superox 702; Norpol Peroxide 1; Syrgis
Andonox KP-9; Akzo Cadox D-50a. Hi-Dimer type catalysts used for VE resins and gelcoats can be used
but can slow down the reaction and can increase exotherm. High hydrogen peroxide content (Luperox
DeltaX-9), low exoterm blends (Andonox KP-9LE) and CHP blends (MCP) catalysts are to be avoided.
MEKP (Arkema Luperox
DDM-9, SG 1.004 g/cc)
1.8% by volume
(minimum 1.25%, maximum 1.8%); set
Geltime* at 24
o
C (75
o
F) R – Regular version
pump slave arm at 1
1
/4, 1
1
/2 and
1
3
/4 % respectively
Geltime* at 29
o
C (85
o
F) S – Summer version
15 – 20 minutes (100 gram mass)
@ 1.8% by volume
Exotherm, 3/8 (10mm) thickness
15 – 20 minutes (100 gram mass)
@ 1.8% by volume
Coverage Less than 54
o
C (130
o
F)
Catalysation
Catalyst levels are stated by volume. If used by weight, adjust catalyst levels taking specific gravity of the various catalysts into account.
Caution: Follow recommended catalyst types and ratios. Do not exceed a catalyst ratio of 1.8% by volume, nor catalyze below
1.25% in hot temperatures. For consistent results, maintain the recommended shop temperature and a constant catalyst ratio.
Crestamould
T27 | Page 2 of 3 | Version: February 2019
Equipment
Crestamould
T27 is dispensed through an internal mix catalyst pumping/ spraying system with a
ram-type equipment such as the Magnum Venus Industries Putty Unit (www.mvpind.com); the GS
Manufacturing BWX Putty Dispensing System (www.gsmfg.com); or Glascraft, (www.glascraft.com).
The spray fan is obtained by selecting larger than normal spray fan angles for the nozzles (i.e. 70
o
nominal
angle). Vertical hang is non-sagging up to 10mm (3/8 ) wet on wet. An alternative to spraying for large
parts is to use a splatter head arrangement. This allows higher output with less overspray but induces
surface texture. to 5mm (3/16 ) can be applied, waiting for a relative cool-down between the passes,
to approx. 43
o
-49
o
C (110
o
-120
o
F). This is repeated until the desired thickness is achieved. The coverage is
1 litre/1mm/m2; or 0.624 gallons/board ft. (12 x12 x1 ).
Application
The first coat is critical. A layer of no more than 3mm (1/8 ) and no less than 1.5mm (1/16 ) should be
uniformly applied and allowed to gel, exotherm and cool down. Duration approx. 1 – 1.5 hours. Once this
first coat is down to room temperature, subsequent coats of 3mm (1/8 ) to 5mm (3/16 ) can be applied,
waiting for a relative cool-down between the passes to approx. 43
o
-49
o
C (110
o
-120
o
F). This is repeated
until the total desired thickness is achieved. Most applications aim for 20 – 25mm (3/4 – 1 ) total thickness
prior to machining. The secondary bonding window is such that no sanding is required between coats if
the job is stopped. The coverage is 1 litre/1mm/m
2
(0.6 gallons per inch per ft
2
). Tool marks are removed
with 40 grit sandpaper. The surface needs no further preparation prior to sanding primer application.
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Machining
Use carbide tools. Use a positive rake; 2,3 or 4 flutes. End-mill tools are used for the majority of the work,
ball-end tools for finishing. Calculate a chip load of 0.4 – 0.5mm (0.015 – 0.020 ) to set the feed rate versus
rpm versus number of flutes. Adjust speeds to avoid overheating or overloading and material pull out. Do
not leave the CNC unattended. Brush or blow off material as it accumulates on flat surfaces. If possible, blow
air at tool-tip. A shop temperature of 24
o
C (75
o
F) and above will improve machining and reduce tool wear.
Colder temperature will make the Crestamould
T27 harder. Remove shavings daily from part.
Caution: Accumulation of shavings that were produced from under- or overcatalyzed material can
generate heat and smoke in extreme cases with charing of the material. To avoid this, maintain
recommended catalyzation percentages (see page 1), remove shavings regularly and fill shavings in
metal drums, pack it down, add water and store outside.
Crestamould
T27 | Page 3 of 3 | Version: February 2019
Additional Information
Shelf life
Crestamould
T27 is a stable product, and adequate long-term storage conditions will result in a shelf life
of 12 months. Do not store outside or in direct sunlight. After this time, the gel time may drift, and should
be checked before use.
Storage
The product should be kept in securely enclosed containers. Storage should be in a dry place and out
of direct sunlight. The temperature should be between 18
o
-25
o
C (65
o
-77
o
F). Allow material to reach shop
temperature before using. Keep containers closed to eliminate styrene evaporation and to avoid change in
properties of the material. Rotate stock to use oldest batch numbers first.
Mixing
Not required.
2019 ScottBader Co Ltd, February 2019
All information on this data sheet is based on laboratory testing and is not intended for design purposes. Scott Bader makes no representations or warranties of any kind
concerning this data. Due to variance of storage, handling and application of these materials, Scott Bader cannot accept liability for results obtained. The manufacture of
materials is the subject of granted patents and patent applications; freedom to operate patented processes is not implied by this publication.
Scott Bader UK
Wollaston
Wellingborough
Northants
NN29 7RL
UK
Tel: +44 (0)1933 663100
email: enquiries@scottbader.com