Ba (6.3.1)

Front 1

What is a composite material?

Back 1

A composite material consists of two (or more) different materials whose mechanical properties complement each other although they maintain
their separate identities (unlike an alloy).

Front 2

In aircraft engineering terms, a composite usually consists of what?

Back 2

a plastic resin matrix and reinforcing fibres of various materials.

Front 3

composite materials are increasingly used in
aircraft construction because of what properties?

Back 3

their strength to weight ratio and corrosion
resistance

Front 4

(Nomenclature of Glass Fibre)

A single fibre of glass usually between 5 and 14
microns (m) in diameter, several times thinner than a human hair. Due to the near perfect surface, it may have an Ultimate Tensile Strength (UTS) of around 3400MPa (E Glass) or 4400MPa (S Glass).

Back 4

Filament

Front 5

(Nomenclature of Glass Fibre)

A lubricant used on the fibres during manufacture, it is burnt off prior to twisting

Back 5

Size

Front 6

(Nomenclature of Glass Fibre)

A compound used to coat the filaments to improve handling and bonding characteristics. It must be compatible with the resin system used. DuPont "Volan A" is a common finish used with glass fibres.

Back 6

Finish

Front 7

(Nomenclature of Glass Fibre)

A number of filaments bonded together with a size

Back 7

Strand

Front 8

(Nomenclature of Glass Fibre)

The weight of a strand in grammes/kilometer,
e.g. 68 TEX = 68g/1000m

Back 8

TEX Count

Front 9

(Nomenclature of Glass Fibre)

Loose combination of strands with no twist.

Back 9

Roving

Front 10

(Nomenclature of Glass Fibre)

One or more strands with applied twist of 20 - 40 turns per metre.

Back 10

Single Yarn

Front 11

(Nomenclature of Glass Fibre)

Two or more single yarns with applied twist in the opposite direction to the single yarn twist.

Back 11

Plied Yarn

Front 12

(Nomenclature of Glass Fibre)

A roll or spool of Roving or Yarn prior to weaving into cloth or chopping for mat.

Back 12

Cheese

Front 13

(Nomenclature of Glass Fibre)

The name given to the longitudinal direction of the fibre in woven fabric, i.e. Warp Yarns; Yarns running the length of the fabric.

Back 13

Warp

Front 14

(Nomenclature of Glass Fibre)

The transverse direction of the fabric, or yarns running crosswise

Back 14

Weft

Front 15

(Nomenclature of Glass Fibre)

A roll of cloth.

Back 15

Bolt

Front 16

(Nomenclature of Glass Fibre)

Woven edge reinforcement of fabric which must be trimmed off before use. Woven tape also has edge reinforcement but this may be incorporated in a repair.

Back 16

Selvedge

Front 17

(Styles of woven fabrics)

Fibres only produce their greatest strength when they are?

Back 17

perfectly straight

Front 18

What kind of weave is this?

Back 18

Four Harness Satin Weave

Front 19

what kind of weave is this?

Back 19

Plain weave

Front 20

Most high strength primary structures are composed of what?

Back 20

uni-directional material

Front 21

what kind of weave is this?

Back 21

2 x 2 Twill weave

Front 22

(storage)

To prevent the condensation of moisture on the cloth before use, the material must be allowed?

Back 22

Reach room tempature

Front 23

Some glass fibre cloth is supplied pre-impregnated with resin (Prepreg) and must be stored in a freezer at what tempature?

Back 23

-18°C or below

Front 24

For the integrity of aircraft repairs, it is essential that the glass cloth is undamaged and not contaminated with oil, grease, dust or moisture. Glass fibre fabric should, therefore, be stored horizontally in suitably protected rolls on cradles at an ambient temperature not exceeding °C and humidity not exceeding % relative humidity

Back 24

20°C and humidity not exceeding 65% relative humidity. Fabric must not be stored flat, folded or on end as the fibres are easily damaged.

Front 25

Aramid fibres are made from?

Back 25

aromatic polyamide

Front 26

Aramid fibre has the ability to?

Back 26

stretch under load then return to its original
shape without breaking

Front 27

However, aramid fibre has a lower ___________ than carbon?

Back 27

compression strength

Front 28

Aramid fibres are resistant to what?

Back 28

high temperatures and fire

Front 29

(Carbon fibres)

The fibres are manufactured by the controlled heating of Polyacrilonitrile (PAN), polythene or rayon fibres (e.g. Courtelle, Acrilan, Orlon) in a furnace filled with an inert gas. The fibres are pre-oxidised at °C?

Back 29

200-300°C for ONE hour

Front 30

(Carbon fibres)

Then carbonised at what?

Back 30

1200°C

Front 31

(Carbon fibres)

then graphitised at what tempature?

Back 31

2000 - 3000ºC

Front 32

(Carbon fibres)

This process removes what?

Back 32

the hydrogen, nitrogen and oxygen leaving long
oriented carbon chains.

Front 33

A low density, high tenacity fibre with good impact resistance but low modulus. Its lack of stiffness usually precludes it from inclusion in a
composite component, but it is useful where low weight, high impact or abrasion resistance, and low cost are required. It is mainly used as a
surfacing material,

Back 33

Polyester

Front 34

In random orientation, ultra-high molecular weight polyethylene molecules give very low mechanical properties. However, if dissolved and drawn from solution into a filament by a process called gel-spinning, the molecules become disentangled and aligned in the direction of the filament. The molecular alignment promotes very high tensile strength to the filament and the resulting fibre. Coupled with their low S.G. (<1.0),

Back 34

Polyethylene

Front 35

A very high silica fibre material similar to glass but with much higher
mechanical properties, good dielectric constant and excellent resistance to high temperatures (>1,000°C). However, the manufacturing process and low volume production lead to a very high price. Because of it’s high strength, low dielectric constant and good transmissivity it is used for radome construction but little else on commercial aircraft.

Back 35

Quartz

Front 36

Carbon or metal fibres may be coated with a layer of boron to improve the overall fibre properties. The extremely high cost of this fibre restricts it use to high temperature aerospace applications and in specialised sporting equipment. composed of carbon fibres interspersed among 80-100mm boron fibres, in an epoxy matrix, can achieve properties greater than either fibre alone, with flexural strength and stiffness twice that of HS carbon and 1.4 times that of boron, and shear strength exceeding that of either fibre.

Back 36

Boron

Front 37

fibres, usually in the form of very short ‘whiskers’ are mainly used in areas requiring high temperature resistance. They are more frequently associated with non-polymer matrices such as metal alloys. what is it?

Back 37

Ceramics

Front 38

(Resins)

Man-made polymers are generally called

Back 38

‘synthetic resins’ or simply ‘resins’

Front 39

(Resin)

like metals, soften with heating and eventually melt, hardening again upon cooling. This process of crossing the softening or melting point on the temperature scale can be repeated as often as desired without any appreciable effect on the material properties in either state. Typical types include nylon, polypropylene and ABS, and these can be reinforced, although usually only with short, chopped fibres such as glass. what kind of resin is it?

Back 39

Thermoplastics

Front 40

(Resin)

formed from a chemical reaction in situ, where the resin and hardener or resin and catalyst are mixed and then undergo a non-reversible chemical reaction to form a hard, infusible crystalline polymer. Heat can be used to accelerate the cure process and also improves the strength of the resin, but overheating damages the molecular bonds

Back 40

Thermosetting Plastics

Front 41

(Resin)

Once cured, thermosets will not become liquid again if heated, although above a certain temperature their mechanical properties will change significantly. This temperature is known as the?

Back 41

Glass Transition Temperature (Tg)

Front 42

(Thermosetting Resins)

Two or three part systems. Good environmental resistance. Heat resistant up to150ºC. Used as wet resin and prepreg, it produces toxic fumes (styrenes) during the cure process. Easily fire retarded but produces a lot of smoke when burning. Not as strong as epoxy. Was used extensively for aircraft but use now diminishing. Can be dangerous if mixed incorrectly (risk of explosion).

Back 42

Polyester

Front 43

(Thermosetting Resins)

Very strong, good environmental resistance. Can
have high temperature resistance (>200ºC). Used
as wet resin, prepreg or adhesive film. Will usually burn readily and produces a lot of smoke when burning

Back 43

Epoxy

Front 44

(Thermosetting Resins)

Used where operation at higher temperatures than bismaleimides can stand is required (use up to 250°C wet/300°C dry). Typical applications include missile and aero-engine components. Extremely expensive resin, which uses toxic raw materials in its manufacture. Polyimides also tend to be hard to process due to their condensation reaction emitting water during cure, and are relatively brittle when cured

Back 44

Polyimides

Front 45

(Thermosetting Resins)

Fairly brittle system but has a good fire/smoke toxicity performance. Hence extensive use in
interior passenger cabin composite components.
Good heat resistance (>200ºc).

Back 45

Phenolics

Front 46

(Epoxy Resins)

These systems are mainly used for components that will meet elevated temperature conditions in service and are most resistant to moisture
absorption. Most major structural items such as airframe class 1 items are based on these resins. what kind of epoxy system is this?

Back 46

350ºf (177ºC) Cure Epoxy Systems

Front 47

(Epoxy Resins)

These systems are used on less highly loaded structures such as fairings and access panels and are less resistant to elevated temperatures and
moisture absorption

Back 47

250ºf (121ºC) Cure Epoxy Systems

Front 48

(Epoxy Wet Resins)

These are usually two part systems

Part A..which is?

&

Part B....which is?

Back 48

Part A:- is a polyepoxide resin (base resin)

Part B:- is a curing agent (hardener)

Front 49

(Epoxy Wet resins)

what is Pot Life?

Back 49

Usable life of resin in the Pot (mixing receptacle). The pot life may be extended by decanting the mixed resin into smaller units because this
reduces the heat generated in the curing resin by exothermic reaction

Front 50

(Epoxy Wet resins)

This is the usable life after resin has been wetted into reinforcement and before it begins to gel.. what is it?

Back 50

Work Life

Front 51

(Epoxy Wet resins)

On addition of the hardener a resin will begin to become more viscous until it reaches a state when it is no longer a liquid and has lost its ability to flow. This is what?

Back 51

Gel Point

Front 52

(Epoxy Wet resins)

Wet resins will usually cure at ambient temperatures _________ºC in _________ hours though they will harden in less time than this. Cure can be accelerated (and properties improved) by the addition of heat.

Back 52

cure at ambient temperatures (21-24ºC) in 16-72
hours

Front 53

(Resin/Fibre Ratio)

Depending on the fibres and resins used different rations will be used. However polyesters ratio is usually about _______ parts of resin to ________ part of fibre by weight

Back 53

two parts of resin to one part of fibre by weight

Front 54

(Prepregs)

What is a prepreg? (an abbreviation of pre-impregnated)

Back 54

is a sheet of fibre cloth or tape impregnated with the resin/hardener system.

Front 55

(Prepregs)

Different kinds of prepegs are available list some different kinds?

Back 55

1. Glassfibre
2. Carbon fibre
3. Aramid
4. Aluminium mesh

Front 56

(Prepregs)

Because the prepreg material contains only enough resin to cure its own fibres it must be bonded to the substrate with a separate adhesive. This is usually in the form of what?

Back 56

A thin layer of thickened epoxy resin known
as film adhesive

Front 57

(Prepregs)

The backing film on cloth and tape material usually has a diamond pattern embossed on it. The long diagonal of the diamond indicates the _______ direction?

Back 57

Warp

Front 58

(Prepregs)

To prevent premature cure, prepregs and film adhesives must be transported and stored at?

Back 58

Very low tempatures

Front 59

(Prepregs)

Prepregs and film adhesives are stored in a sealed bag at?

Back 59

-18ºC

Front 60

(Workshop Conditions for Good Bonding)

(Storage)

If applicable allow kits of resin to reach ambient temperature before opening. Resin storage categories: List the label colour and temperature of each Category?

• Category A
• Category B
• Category C

Back 60

• Category A Blue Label -18ºc and below
• Category B Yellow Label 1ºc to 5ºc
• Category C Red label Ambient

Front 61

(Composite Construction)

Fibre reinforced plastic resins can be used as?

Back 61

• Laminate
• Sandwich

Front 62

(Composite Construction)

Describe a Laminate?

Back 62

A structure built-up from layers of cloth impregnated with resin

Front 63

(Composite Construction)

Describe a Sandwich?

Back 63

laminated skins separated by a light weight core,

Front 64

(Composite Construction)

Sandwich construction represents by far the most common use of composite materials on most aircraft. This structure consists of two
laminated skins separated by a crush resistant core. This gives an “I” beam type construction with skins carrying the what load?

Back 64

tension and compression loads

Front 65

(Composite Construction)

And the core takes what load?

Back 65

shear loads

Front 66

(Composite Construction)

This ‘honeycomb’ structure can be made
from?

Back 66

• glass fibre
• aluminium
• Nomex ( resin impregnated aramid fibre ‘paper’.)

Front 67

(Composite Construction)

Nomex offers what ratio of its properties?

Back 67

very high strength to weight ratio and excellent resistance to moisture and fire

Front 68

(Composite Construction)

The cell size of a honeycomb dictates what properties?

Back 68

density, weight and strength of the honeycomb
material.

Front 69

(Composite Construction)

Label the parts and name the honeycomb structure?

Back 69

"HEX CORE"

Front 70

(Composite Construction)

Name the honeycomb structure?

Back 70

"OX-CORE"

Front 71

(Composite Construction)

Name the honeycomb structure?

Back 71

"FLEX CORE"

Front 72

(Composite Construction)

The advantages of monolithic structures include?

Back 72

weight reduction compared to conventional construction

Front 73

(Composite Construction)

Non-conductive materials such as glass and aramid composite panels are often treated with a coat of what?

Back 73

conductive paint, or have a metallic mesh
ply included in their lay-up to aid electrical bonding

Front 74

(Composite Cure)

What is an autoclave?

Back 74

Autoclaves are pressurised ovens ranging in size from bench-top units to large plant with a working chamber large enough to accommodate a fuselage section or whole wing box

Front 75

(Composite Cure)

For aerospace use these autoclaves produce how many bars of pressure? and apply what tempature?

Back 75

they apply a pressure of around 15 bar and temperatures up to about 250°C.

Front 76

(Composite Cure)

is a portable computer based control unit which may be used to perform repairs in situ on the aircraft. It can be programmed to control the heating devices and produce a vacuum to compact the repair while recording the values achieved during the cure cycle. what is it?

Back 76

"Hot Bonder"

Front 77

(Composite Cure)

Heat may be provided by lamps or more commonly electrical mats. It is monitored by what?

Back 77

Thermocouples

Front 78

(Inspection and Damage Assessment)

Some of to day’s more common methods of Non-Destructive Inspection?

Back 78

• Ultrasonic Inspection
• Radiography
• Vibration Methods
• Thermal Imaging
• Spectroscopy

Front 79

(Inspection and Damage Assessment)

Thermal photography (Thermography) can be used to survey large areas of the airframe in service and will reveal water damage. The area of interest is photographed or scanned with a thermal imaging camera immediately after landing. Any water in the structure will act as a heat sink and will appear as a cold point on the structure..what is this?

Back 79

Thermal Imaging

Front 80

(Inspection and Damage Assessment)

The scanner fires a low power laser at the surface and analyses the reflection. Once calibrated on a suitable test piece it will give a quite accurate reading of the maximum temperature encountered by the structure under examination... what kind of inspection is this?

Back 80

Spectroscopy

Front 81

(Composite Repairs)

Name this sanding repair?

Back 81

Step sanding

Front 82

(Composite Repairs)

Name this sanding repair?

Back 82

Taper sanding

Front 83

(Composite Repairs)

Mix sufficient resin to bond in lower repair ply and core. Work resin into cloth between melamine sheets, cut to size/shape, peel melinex from one side, place in hole in correct orientation and remove other melinex. what kind of repair is this?

Back 83

Wet Lay-up

Front 84

(Composite Repairs)

Remove one backing paper and lay film adhesive in hole. Remove other backing paper and insert repair ply/s observing orientation. Apply film
adhesive onto repair ply/s. Wrap foaming adhesive round core plug and insert observing ribbon direction. What kind of repair is this?

Back 84

Prepreg Lay-up

Front 85

(Cutting and Drilling Composites)

Great care needs to be employed when cutting and drilling composites. Due to their nature, glass and carbon fibres will prematurely do what to metal edges very quickly?

Back 85

Blunt them

Front 86

(Cutting and Drilling Composites)

Generally high speeds and low feeds are required and ____________ cutting tools will give longer life and better finish?

Back 86

Carbide

Front 87

(Cutting and Drilling Composites)

For trimming material, to get the best results we use?

Back 87

diamond grit cutters and silicon carbide abrasives

Front 88

(Cutting and Drilling Composites)

The drills normally specified will be either shallow ________ ________ multi-start bits (e.g. “Klenk” drills) or flat bladed drill/__________ (“Dreamers”). These will be used to open holes produced by tungsten carbide pilot drills.

Back 88

helix angle

&

Reamer

Front 89

(Fibre/Metal Laminate (FML))

Currently a glass fibre/aluminium composite known as ‘___________’ is being used to form the upper skin panels of the Airbus A380?

Back 89

GLARE

Front 90

(Fibre/Metal Laminate (FML))

This material is both __________ than conventional sheet metal, and has better _________ resistance and lower ____________ propagation

Back 90

1. Lighter
2. Fatigue
3. Crack

Front 91

(Fibre/Metal Laminate (FML))

GLARE has very good ________________properties, but limited resistance to ___________ loads. Its use is, therefore, restricted to areas of predominant tensile load such as the fuselage crown skin area.

Back 91

1. tensile strength
2. compressive

Front 92

(Other Non-metallic Materials)

Plastics
As we have seen, there are two groups of plastics;

1. become soft when heated and can be
   moulded again and again.
2. become permanently hard during the
   moulding process and cannot be softened
   again.

Back 92

1. Thermoplastic materials
2. Thermosetting materials

Front 93

(Plastics)

PVC is a thermoplastic material often used to replace rubber for making protective gloves and aprons. It is also used to make seat covers in light aircraft. A plasticiser can be added to PVC to soften it. PVC can be shaped by injection moulding and extrusion. It can also be compression moulded without a plasticiser to give a tough rigid material.

Back 93

Polyvinyl Chloride (PVC or Vinyl)

Front 94

(Plastics)

Produced under brand names such as DuPont's 'Teflon', PTFE is a fluorocarbon-based polymer which has a very high resistance to most chemicals at temperatures from -80°C to>200°C and very low friction

Back 94

PolyTetraFluoroEthylene

Front 95

(Plastics)

Laminates are made by pressing together sheets of cotton or linen which have been soaked in a thermosetting plastic resin.
These laminates are tough, have a high electrical resistance and can be drilled and machined successfully. Among other things, they are used to make control system pulleys,

Back 95

Tufnol and Micarta Laminates

Front 96

(Plastic Transparencies - Perspex)

For aircraft purposes, formed Perspex is supplied in two grades:

What is Grade One perspex?

What is Grade Two perspex?

Back 96

Grade one:- which is free from optical distortion on both flat andcurved surfaces. Used for panels where undistorted vision is essential

Grade Two:-which may have slight irregularities and some optical distortion. Used for passenger windows, lamp coversetc., and authorised repairs.

Front 97

(Elastomers)

Elastomers will tolerate repeated ____________ and return to their original size and shape, in a similar way to natural rubber. Some of the more common ______________,

Back 97

• Elongation
• Elastomers

Front 98

(Elastomers)

Some of the more common elastomers, to be found in the aerospace industry include;

Back 98

• Nitrile
• Fluoro-Elastomers
• Neoprene
• Silicone Rubber
• Ethylene-propylene rubbers - (EPM and EPDM)
• Poly-Sulphide Rubber

Front 99

(Ceramics)

for applications where dust and moisture readily collect. These materials can be moulded into special shapes before being fired and glazed rather as crockery is. The porcelain-type insulators on high-voltage transformer and switch gear bushings, and on high-voltage
transmission and distribution overhead lines, are probably their most familiar use... what kind of ceramic is this?

Back 99

Porcelain and Steatite

Front 100

(Ceramics)

have been used for some times for such applications as motor vehicle spark-plug insulators and special electrical components.
Advanced ceramics are under development for use in gas turbine engines for high temperature stators and turbine blades... what kind of ceramic is this?

Back 100

Special ceramics

Front 101

(Ceramics)

is used for flight deck windows. Due to the high impact resistance and low erosion requirements they are usually composed of laminations of soda-lime glass, toughened glass and acrylic material with heating elements built in. The composition varies with type and manufacturer.. what is it?

Back 101

Glass

Front 102

(Ceramics)

compositions are for high temperature insulation applications. what is it?

Back 102

Mica-glass

Front 103

(Ceramics)

Are used in heat resistant blankets and to weave
fireproof cloth for engine and pylon protection

Back 103

Ceramic Fibres

Front 104

(Adhesives)

What kind of adhesive bond is this?

Back 104

Mechanical

Front 105

(Adhesives)

What kind of adhesive bond is this?

Back 105

Chemical

Front 106

(Adhesives)

Types of bond

Mechanical?

Back 106

here the adhesive penetrates into the surface and forms a mechanical lock, by keying into surface irregularities. It also forms re-entrants, where the adhesive penetrates behind parts of the structure, and becomes an integral part of the component to be joined.

Front 107

(Adhesives)

Types of bond

Chemical?

Back 107

in this method of bonding, the adhesive is spread over the surfaces to be joined and forms a chemical bond with the surface, it's molecules diffusing into the substrate.

Front 108

(Adhesives)

Stresses on a bonded joint
Adhesive joints are liable to experience four main types of stress; what are they?

Back 108

1. Tensile
2. Shear
3. Cleavage
4. Peel

Front 109

(Adhesives)

The major disadvantages associated with adhesive bonding are?

Back 109

• Limited heat resistance, normally below 200ºC
• Poor electrical and thermal conductivity
• High thermal expansion
• Limited resistance to certain chemicals such as paint strippers
• Integrity difficult to check with non-destructive testing procedures

Front 110

(Types of adhesive)

Flexible adhesives are used when?

Back 110

Flexible adhesives are used when some flexing, or slight relative movement of the joint, is essential and where high load-carrying properties are not paramount. In general, flexible adhesives are based on flexible plastics or elastomers. They are used for internal decorative trim etc. Examples include Evostik and Tretobond.

Front 111

(Types of adhesive)

Structural adhesives are primarily aimed at?

Back 111

aimed at applications where high loads
must be carried without excessive creep. They are relatively rigid without being excessively hard or brittle. Structural adhesives are based on
resins, (the most common ones being epoxy or polyester). Examples include Scotch-Weld and Hysol products

Front 112

(Adhesives)

Various acids can be used for the etch process including hydroflouric acid and sulphuric acid. Appetures and crevices must be sealed prior
to application.

The Phosphoric Acid Non-Tank Anodising (PANTA) process is commonly used. The prepared area is coated with phosphoric acid gel and layers of gauze and acid gel laid on top. A stainless steel mesh is placed above this and coated with the gel. The work piece and mesh are connected to a DC power source so that the skin forms the anode (+) and the mesh
is the cathode (-). A charge of 6 volts at 1-7 amps/ft2 is applied for 10-12 minutes. The area must be cleaned with running water for 5 minutes with a maximum delay of 21/2 minutes. The area must then be dried for
at least 30 minutes? Name the surface treatment?

Back 112

Acid etching/anodising of existing surface

Front 113

(Adhesives)

The adequacy of the anodising must be checked. This is done by observing the surface through a filter with fluorescent or daylight at a low angle of incidence. Rotating the filter will cause the original colour to change to a complimentary colour. If the colour change is not observed or is patchy, the cleaning and anodising processes must be repeated... what kind of test is this?

Back 113

Polarised light test

Front 114

(Adhesive)

Within 2 hours of anodising, the area must be reprotected with primer. Normally an epoxy based Adhesive Bonding Primer is specified producing a coating 0.00015 - 0.0004 thick. This should be air dried or infrared heated to 93°C (200°F). Some primers require curing at 93°C (200°F) and this should be done within the specified time period... what is this?

Back 114

Epoxy priming

Front 115

(Adhesive)

Repair assembly is similar to ___________ composite lay-up.

and is called?

Back 115

Prepeg

Repair Lay-up

Front 116

(Jointing Compounds)

These materials are sometimes known as 'yellow chromate' or 'zinc chromate' or by trade names such as Duralac, JC5A and more recently Mastinox. They are used for the wet assembly of metallic mating surfaces in non-pressurised areas. Available in tubes, cans and drums, aircraft grade compounds do not dry and remain flexible throughout their working
life.

Back 116

Chromate Based Jointing Compounds

Front 117

(Jointing Compounds)

Hylomar is one of several sealants used on bolted flange joints for engine and component assembly. It seals metal to metal joints and is resistant to water, fuel, oil, most chemicals and combustion products. It seals surfaces with imperfections and withstands vibration, heat and expansion?

Back 117

Hylomar

Front 118

(Sealants)

Typical of the multi part sealants used is _______________. This two part polysulphide compound is comprised of a base and an accelerator and
is used for sealing integral fuel tanks, pressurised cabins, and for faying surfaces. It is resistant to aircraft fuels, lubricating oils, and Skydrol Hydraulic Fluid.

Back 118

PR 1440

Front 119

(Sealant Application)

The length of time it takes for the sealant to be no longer tacky or sticky? is called what?

Back 119

Tack Free Time

Front 120

(Sealant Application)

Application Time for PR 1440

(Type A1/2)

&

(Type A2)

Back 120

(Type A1/2) = 30 mins

(Type A2) = 2 hours

Front 121

(Sealant Application)

Tack free time for PR 1440

(Type A1/2)

&

(Type A2)

Back 121

(Type A1/2) = <10 hours

(Type A2) = < 36 hours

Front 122

(Sealant Application)

Cure time for PR 1440

(Type A1/2)

&

(Type A2)

Back 122

(Type A1/2) = 30 hours

(Type A2) = 72 hours