The subject prepares the student for industry as it specifies all application techniques in surface treatments. These are commonly used in all the paint related industries.
1 Objective of surface preparation and the phenomena, mechanical surface preparation, flame cleaning, blast cleaning etc. chemical surface preparation, solvent wiping and degreasing, alkali cleaning, emulsifiable solvent cleaning, steam cleaning, acid cleaning, pickling, phosphoric acid, electrolytic pickling. (10 hrs)
2 Chemical paint removal such as alkaline and solvent type removers etc. pretreatment chemical conversion coatings based on zinc manganese iron and chromium etc., cromate and other treatments, substrates and their specific preparations.
3 Common application techniques, importance of rheological behavior in paint application, brush application, conventional air spray, airless spray. Hot spray, duel component spray, electrostatic handgun and high speed disc systems dipping roller and coil coating, powder coating, electrode position principles, miscellaneous application techniques, vacuum impregnation, curtain coating, flow coating, silk screen slush coating, knife coating, calendar coating, centrifugal coating etc. (16 hrs)
4: Curing of wet film paint shop services, paint shakers or tumblers, paint and distribution system, waste treatment, paint shop troubles, inspection and service complains, finishing of specific items, motor, body, refrigerator and domestic appliances, machinery and casting. (06 hrs)
5: Paint defects, sources, leveling, sagging, drip marks, crawling, cratering, wrinkling, peeling, classification, defects in the liquid paint, defects during application, defects during drying or curing, defects in the dry film in use, causes and rectification of defects and preventive measures refinishing and maintenance finishing. (06 hrs.)
Practical aspects of surface treatment and application of techniques should be shown by visits to paint auto shop plants.
LIST OF PRACTICALS
1. Study of different surfaces and their preparation for coatings.
2. Removal of paints from different substances:
i) use of sand paper
ii) use of solvents
iii) double coating layers
3. Oil and Cup viscometer, measurements of flow of different formulations vis-à-vis:
i) for different applications
ii) effect of additives
iii) effect of pigments
iv) effect of resins
v) Gardner Tube method Viscosity ( A+OZ)
4. Various application techniques:
iii) Applicator (thin film)
v) Dip coating
vi) Knife coating
5. Analysis of defects in coatings.
Different defects: leveling, sagging, etc. use of microscopy and visual
6. To find the grindness of Paint/Primer