CHAPTER 13 - BONDING AND SEALANTS Flashcards
IMPORTANCE F SEALANTS
What are sealants used for?
To isolate one environment from another
IMPORTANCE OF SEALANTS
What 2 places are sealants used?
- On faying surfaces
- To form beads and fillets over joints
TYPICAL MULTI PART SEALANT
What is the typically used multi-part sealant?
PR 1440
TYPICAL MULTI PART SEALANT
What is PR 1440?
A two-part polysulphide compound comprised of a base and an accelerator
Used for sealing integral fuel tanks and faying surfaces
TYPICAL MULTI PART SEALANT
How is PR 1440 available?
Type A: ‘Brush’ type sealant
Type B: ‘Non-brush’ for fillet seals and encapsulation
TYPICAL MULTI PART SEALANT
What are the two typical applications times PR 1440 is available in?
30 minutes
2 hours
TYPICAL MULTI PART SEALANT
What is included in a ‘Semkit’ cartridge?
The correct quantities
An integral accelerator
Mixing facility
TYPICAL MULTI PART SEALANT
What is the Application time?
Time it takes for the mixed sealant remains suitable for application
TYPICAL MULTI PART SEALANT
What is the Tack Free Time?
Length of time it takes for the sealant to be no longer tacky or sticky
TYPICAL MULTI PART SEALANT
Define what the Curing Time is..
This is the time it takes for a chemical cure to take place. it depends on temperature and relative humidity
TYPICAL MULTI PART SEALANT
What is Assembly Time?
The time that all riveting/fastening must be completed
TYPICAL MULTI PART SEALANT
What 3 things are ensured with surface preparation before a sealant is applied?
- Surfaces must before cleaned properly
- Products must be corrects prepared
- Products must be applied correctly
TYPICAL MULTI PART SEALANT
What is the maximum thickness a sealant should not exceed?
0.030”
TYPICAL MULTI PART SEALANT
What should be done to ensure a faying surface is completely sealed with sealant?
A small continuous fillet of sealant should be squeezed out on both sides of the overlap and smoothed into the joint when riveting is completely
RTV SEALANT
What does RTV stand for with sealants?
Room Temperate Vulcanising (RTV) silicone rubber
RTV SEALANT
What smell do some RTV sealants give off as they cure?
Acetic Acid (Vinegar) odour
RTV SEALANTS
What are the 5 typical examples of one-part RTVs?
Also state what they would be used for..
- White General Purpose - for general use (with drinking water and food etc.)
- White Electrical Grade - high electrical resistance - used for repair insulation
- Grey High Strength - used where durability is required
- Red High Temperature - used on pipe sleeves and insulation on engines and APUs
- Translucent - Decorative (used on galley and toilet compartment etc.)
RTV SEALANT
What specialist applications are one and two part RTV silicone adhesive/sealants used for?
6 EXAMPLES IN THE TTN
Levelling compounds, potting compounds, heat sinks, thermal barriers, foaming fillers, release against etc.
HYLOMAR
What are the 3 main advantages for using HYLOMAR?
Resistant to water, fuel, oil, most chemicals and combustion products
Seals surfaces with imperfections
Withstands vibration, heat and expansion
REDUX BONDING
What is Redux a generic name for?
A family of certain adhesives
REDUX BONDING
What, how and where is Redux 64 used?
A LIQUID based adhesive used HOT and under pressure for bonding gaskets on STEEL, CAST METAL AND ALUMINIUM
REDUX BONDING
What, how and where is Redux 775R used?
Is a LIQUID and POWDER adhesive used WARM and under pressure for bonding METAL TO ITSELF
REDUX BONDING
How soon should redux be bonded after preparation?
Within 8 hours of preparation
