Applications

Domestic appliances are a very important part of these coatings.  In our design-conscious era, they need to be as special in their looks as in their function. This is where Talisman Thermocure Powder Coatings can assist. As the experienced powder paint persons with their long history in Indian powder coatings industries, we have first class expertise in color and color trends.

The product range has been designed to meet the particular demands of the domestic appliance manufacturer: Hot water resistance, durability and scratch-resistance, high performance, UV-protection, corrosion shield, chemicals resistance, coating flexibility, efficient application, easy-clean.

Application of the powder: Substrate Pretreatment Prior to Coating.

The main aims in the preparation of a metal surface prior to powder coating may be defined as follows:
1) The complete elimination of all foreign matter, e.g. Scale, grease, cutting oil, soil, welding splatter, etc.
2) The taming of the surface so as to make it suitable for the coating.
3) The pretreatment should pass on equality throughout all treated surfaces,

Pretreatment stage is essential and critical in order to get the full prospective of the powder coating. Surface pretreatment may vary depending upon the specific end-use of the finished products from a single-step cleansing operation to a multi-stage stylish pretreatment which deposits a conversion coating on the surface of the metal. Application by electro statically charged particles to an earthed metal surface can only be achieved if the surface is free of any composition which has a high electrical resistance. The presence of any resisting film on the surface of the article to be coated will reduce or some times prevent powder deposition on the earthed article.

Substrates/Metals- Steel, aluminum, copper, zinc alloys and galvanized steel are common metals for powder coatings.
Steel - For iron/steel surfaces maximum corrosion and salt spray resistance are given by a zinc phosphate conversion coating.
Aluminum - For aluminum and its alloys, although the clean surfaces are easily coated and adhesion is excellent, performance can be enhanced by a chromate conversion coating.
Zinc alloys - With all zinc based substrates such as Zintec, Mazac and Galvanized Steel a suitable phosphate coating is recommended.

The application of the powder is possible by corona charging and tribo charging also.
The powders are adhered to the substrate due to its mirror charges of the charged particles which acts as two different poles of a capacitor.

COMPARISOM CHART FOR CHEMICAL RESISTANCE

CHEMICAL

EPOXY

HYBRID

PE-TGIC

HCL 20%

EXCELLENT

GOOD

GOOD

HNO3

GOOD

POOR

POOR

SULPHURIC ACID 50%

GOOD

FAIR

FAIR

HF 20%

GOOD

POOR

POOR

FORMIC ACID 90%

EXCELLENT

POOR

POOR

GLACIAL ACETIC ACID

NOT RECOMMENDED

POOR

POOR

CHROMIC ACID 5%

FAIR

POOR

POOR

NH4OH

EXCELLENT

POOR

POOR

NaOH

EXCELLENT

FAIR

POOR

HC SOLVENTS

EXCELLENT

GOOD

GOOD

MEK

FAIR

FAIR

FAIR

ETHANOL

EXCELLENT

EXCELLENT

EXCELLENT

PETROL

EXCELLENT

EXCELLENT

EXCELLENT

MINERAL OILS

EXCELLENT

EXCELLENT

EXCELLENT

CHLORINATED HC

FAIR

POOR

POOR

BENZENE

EXCELLENT

FAIR

FAIR

 

Trouble shooting chart.

TROUBLE SHOOTING GUIDELINES FOR APPLICATION OF POWDER COATINGS.

 

A.      FLUIDISED BED PROCESS IN HOPPER

          

A-1

POWDER BLOWING OUT OF THE HOPPER

 

 

 

 

1 .

AIR PRESSURE TOO HIGH

 

1.  ADJUST THE PRESSURE.

 

 

2 .

TOO FINE POWDER PARTICLES

 

2a. TOO MUCH RECLAIM ADDED TO THE VERGIN

 

 

 

 

 

      POWDER.

 

 

 

 

 

 

 

 

2b. TOO FINE ORIGINALLY MANUFACTURED

 

 

 

 

 

 

      POWDER : CONTACT POWDER MANUFACTURER

A-2

NO AIR PERCOLATION THROUGH

 

 

 

 

 
 

THE POWDER.

              

1 .

INSUFFICIENT AIR PRESSURE

 

1. CHECK AIR SUPPLY LINE.

 

 

2 .

PLUGGRD MEMBRANE

 

 

2a. CHECK THE MEMBRANE

 

 

 

 

 

 

 

2b. CHECK THE AIR PURITY

 

 

3 .

COMPACTED POWDER

 

 

3.   TRY TO LOOSEN THE POWDER MANUALLY

 

4 .

POWDER LIVEL IN THE HOPPER TOO HIGH

 

4.   REMOVE PART OF THE POWDER.

5 .

POWDER PARTICLES TOO FINE

 

5a.  TOO MUCH RECLAIM ADDED IN VERGIN POWDER

 

 

 

 

 

5b. TO FINE VERGIN POWDER: CONTACT PC MFGR.

A-3

AIR BLOWING CANALS (LARGE HOLES) THROUGH THE POWDER

 

 

 

 

1 .

POWDER LEVEL TOO LOW

 

1.   ADD MORE POWDER. KEEP HOPPER 2/3 FULL

2 .

PACKED OR MOIST POWDER

 

2a. TRY TO LOOSEN THE POWDER MANUALLY.

 

 

 

 

 

 

2b. CHECK THE HUMIDITY OF THE COMPRESSDE AIR

3 .

BLOCKED POWDER

 

 

3.   CHECK THE Tg OF THE POWDER COATING , IFTOO LOW CONTACT THE POWDER PRODUCER

4 .

MEMBRANE OBSTUCTED

 

4.  CHECK THE BOTTOM OF THE BED

5 .

PLUGGED OR BROKEN MEMBRANE

 

5.  CHECK THE MEMBRANE.

 

 

 

A-1

FLUCTUATION IN THE COATING THICKNESS

 

 

 

 

1 .

IRREGULAR POWDER FEED.

 

1a.  CLEAN POWDER FEED HOSES,PUMP VENTURIS AND GUN.

 

 

 

 

 

1b.  CHECK THE HUMIDITY OF THE AIR SUPPLY WHICH        CAN CAUSE POWDER COMPACTION.

 

 

 

 

 

1c. CHECK POWDER FREE FLOWING PROPERTIES.

2 .

INADEQUATE GUN DISTANCE TO THE WORKPIECE

2.   READJUST THE DISTANCE BETWEEN GUN AND WORKPIECE

3 .

INADEQUATE CONVEYER SPEED IN RELATION TO THE HIGH VOLTAGE OF THE GUN.

 

3.  READJUST THE CONVEYER SPEED.

 

4 .

HIGH VOLTAGE FLUCTUATIONS

 

4.  SYSTEMATICALLY CHECK ELECTRICAL CONTINUTY      FROM THE VOLTAGE SOURCE TO THE ELECTRODE

5 .

POWDER BLOWN OFF FROM THE WORKPIECE

 

5a. POWDER DELIVERY AIR TOO HIGH. TURN DOWN  AIR SETTING.

 

 

 

 

 

5b. MOVE GUN POSITION FURTHER AWAY FROM   THE WORKPIECE

6 .

PRESSURE FLUCTUATIONS IN THE AIR SUPPLY SYSTEM.

6.  CHECK THE AIR SUPPLY SYSTEM.

 

A-2

POOR POWDER BUILD-UP AND WRAP ON THE WORKPIECE:

 

 

1 .

POOR EARTHING

 

 

1.  CHECK THE EARTH CONNECTIONS. ALL CONTACT      AREAS MUST BE FREE OF POWDER BUILD, GREASE OR OTHER INSULATING MATERIAL.

2 .

POWDER OUTPUT TOO HIGH

 

2.  TURN DOWN POWDER FEED UNTIL ADEQUATE CHARGING IS OBTAINED.

 

3 .

ELECTROD(S) INSULATED BY POWDER LAYER

3.  CLEAN THE ELECTROD(S)

 

 

4 .

PARTICLE SIZE DISTRIBUTION NOT IDEAL

4.  TOO MUCH RECLAIM ADDED TO THE VERGIN POWDER

A-3

POOR PENETRATION INTO RECESSES AND GAPS(FARADAY CAGES)

 

 

1 .

GUN VOLTAGE TOO HIGH

 

1. TURN VOLTAGE SETTING DOWN.

2 .

POWDER DELIVERY TOO LOW

 

2. TURN UP POWDER DELIVERY AIR SETTING

 

3 .

POOR EARTHING

 

 

3. CHECK EARTHING CONNECTIONS AND CONTACT AREAS
.

4 .

INADEQUATE GUN POSITION

 

4. ADJUST THE GUN POSITION SO THAT POWDER CLOUD  HAS A  DIRECT PATH TO THE RECESS AREA.

5 .

THE SPRAY PATTERN IS TOO WIDE

 

5. WRONG DEFLECTOR PLATE.CHANGE IT.

 

6 .

DELIVERY AIR SPEED IN THE GUN TOO HIGH

6. LOWER THE AIR VELOCITY.

 

 

A-4

BACK-IONISATION - POWDER REPELLED FROM THE WORKPIECE IN SPOTE.

 

1 .

VOLTAGE TOO HIGH

 

 

1. TURN DOWN VOLTAGE SETTING

 

 

2 .

GUN TOO CLOSE TO THE WORKPIECE

2. RELOCATE THE GUN.

3 .

TOO FINE POWDER PARTICLE SIZE

 

3a. TOO MUCH RECLAIM ADDED TO THE VERGIN POWDER.

 

 

 

 

 

3b. ORIGINALLY DELIVERED POWDER IS TOO FINE.      CONTACT POWDER SUPPLIER

B.  

PROPERTIES OF THE CURED FILM:

 

 

 

 

 

B-1

POOR IMPACT RESISTANCE.

 

 

 

 

 

 

1 .

UNDER CURED FILM

 

 

1. INCREASE OVEN TEMERATURE OR INCREASE STOVING TIME.

2 .

TOO HIGH FILM THICKNESS

 

2. READJUST THE APPLICATION EQUIPMENT.

 

3 .

POOR CLEANING OF PRETREATMENT

3. CHECK PREPREATEMENT EQUIPMENT AND CHEMICALS.

4 .

POWDER COATING FORMULATION PROBLEM

4. CONTACT POWDER COATING MANUFACTURER.

B-2

POOR ADHESION / POOR COROSION RESISTANT.

      

1 .

POOR CLEANING OF PRETREATMENT

1. CHECK PREPREATEMENT EQUIPMENT AND CHEMICALS.

2 .

UNDER CURED FILM

 

 

2. INCREASE OVEN TEMERATURE OR INCREASE STOVING TIME.

3 .

POWDER COATING FORMULATION PROBLEM

3. CONTACT POWDER COATING MANUFACTURER.

B-3

FILM HARDNESS TOO LOW / POOR CHEMICAL RESISTANCE.

    

1 .

UNDER CURED FILM

 

 

1. INCREASE OVEN TEMERATURE OR INCREASE STOVING TIME.

2 .

POWDER COATING FORMULATION PROBLEM

2. CONTACT POWDER COATING MANUFACTURER.

B-4

POOR FILM FLOW - ORANGE PEEL EFFECT.

        

1 .

TOO  LOW FILM THICKNESS

 

1. INCREASE THE FILM THICKNES.

 

 

2 .

TOO SLOW HEATING RATE

 

2. INCREASE THE HEATING RATE.

 

 

3 .

TOO FAST CURING SYSTEM

 

3. CONTACT POWDER MANUFACTURER.

 

4 .

TOO COARSE POWDER PARTICLES

 

4. CONTACT POWDER MANUFACTURER.

 

B-4

CRATERS IN THE FILM (CISSING)

          

1 .

OIL OR GREASE RESIDUES ON THE METAL SURFACE.

1. CHECK THE PRETREATMENT.

 

 

2 .

OIL IN THE COMPRESSED AIR

 

2. CHECK THE AIR SUPPLY SYSTEM.

 

 

3 .

CONTAMINATION WITH SILICON

 

3. CLEAN THE SPRAYING.

 

 

4 .

CONTAMINATION  WITH SILICON OILS FROM THE CHAIN LUBRICATION

4. CLEAN THE SPRAYING AREA THOROUGHLY

 

5 .

CONTAMINATION WITH THE INCOMPATIBLE POWDER

5. CLEAN THE APPLICATION INSTALATION THOROUGHLY

B-5

PINHOLES IN THE FILM

            

1 .

MOISTURE CONTENT OF THE POWDER TOO HIGH

1a. CHECK THE POWDER STORAGE CONDITIONS.

 

 

 

 

 

 

1b. CHECK HUMIDITY OF THE AIR SUPPLY.

 

2 .

AIR INCLUSIONS(DUE TO POROUS OBJECT)

2. PREHEAT THE WORKPIECE(BEFORE APPLICATION) TO TEMPERATURE JUST ABOVE THE STOVING TEMPERATURE.

B-6

BUBBLES IN THE FILM

            

1 .

WATER ON THE WORKPIECE

 

1. CHECK THE DRIER AND WORKPIECE HANGERS

 

2 .

POWDER FILM TOO THICK(ESPECIALLY IN THE CASE OF POWDERS, CONTAINING CAPROLACTUM BLOCKED ISOCYANATES, PRIMID OR POWDERLINK 1174.

DECREASE FILM THICKNESS.