All parts to be coated will be cleaned by adapted treatment in ALKALINE or acid solution before chemical conversion coating. Chemical conversion coating will be carried out according to DIN
50939. The amount of the conversion coating deposited depends on the type which was used and shall be within the limits specified by the conversion coating of the chemical supplier. The
conversion coating shall be thoroughly raised with demineralised water and then dried at the temperature and for the time specified by the chemical supplier.
The quality control tests shall be carried out on finished products but the full range of test shall be done on test panel processed concurrently with production. The test panel shall be prepared from mill finish aluminium sheet with the size of 200x200x1 mm thickness. Test panel will be processed along with production material in accordance to BS 9596.
BS 3900 : PART D1 / QUALICOAT
When a coated test panel/painted profile is examined under defused day light, the color of
coating shall match the reference color nominated by the supplier or as per TALCO internal
standards. The color difference (E Value) of the painted materials shall be < 1 for the light
shades and < 3 for dark shades W.R.T standard reference nominated by supplier.
In case of metallic coating finishes, the shade can be seen at different angles which is the basic property of the color itself. In such cases, mutual agreement of the process (upon sample approval) by both the parties is carried out further.
The organic coating shall be of even color and gloss with good hiding power. When viewed on
site, these criteria shall be fulfilled as follows.
For parts outside: viewed at a distance of 5mts.
For parts used inside: viewed at a distance of 3mts.
B-2) GLOSS :- ISO-2813
BS 3900 : PART D5
This is when finish on each significant surface of the coated test piece or profile using incident light at 60 normal to the surface, the gloss level of the finish shall be.
FOR MAT. FINISH : gloss level should be less then 30 units.
FOR STAIN FINISH: Gloss level should be 45+5 units.
FOR MEDIUM FINISH: Gloss level should be 70+7 units.
FOR HIGH CLASS: Gloss level should be 95+7 units.
NOTE: If the significant surface is too small or unsustainable for gloss to be measured with the gloss meter, gloss should be compared visually with reference sample.
B-4) COATING THICKNESS:- ISO-2360
BS 3900 : PART C5
The thickness on any significant surface that requires a limited thickness of finish as indicated on suitably marked specimens or on technical drawings shall be not more than 12 microns. The substrate shall not be visible at the edge of any significant surface.
In case of metallic finishes, the coating thickness shall be within 60-70 microns.
When the thickness on each significant surface of the coated test piece is tested with a minimum of three determinations, the substrate shall not be visible, the thickness of point shall be not less than 40 micron and the shade should also match with standard sample panel. In case of 2 coat finishes, the 1st coat thickness shall be within 60-70 micron and 2nd coat (clear Coat) will be 40-50 microns. Two coat PVDF liquid coating: – 35 microns, three-coat metalized PVDF
liquid coating = 45 microns. The powder coating thickness will be less at the corners of the
profiles due to faraday cage effect as indicated next page.
NOTE: The control of the thickness of the finish is technically difficult and is very dependent of the geometry of the sections to be coated, so it may not always be possible to achieve a
specified maximum thickness whilst maintaining a minimum thickness of 40 microns. In case of customer demands to increase lower limits thickness of 40 microns. Then higher limit is ignored attempt will be made to control only after customer’s approval.
As a rule, on second coating should be applied on rejected or rework material, should it become
necessary to apply, a second coating nevertheless adapted pretreatment (before painting) is
necessary to guarantee that the adhesion of second coat is good.
The average coating thickness on any significant surface as indicated on suitably marked
specimens of technical drawing shall not be more than 160-180 micron and 100-120 microns for
metallic finish after re-coating. No over coating is advisable on different shade.
B-4.2) PAINT SURFACE AREA COVERAGE:-
Powder coating shall be done in reference to the EXPOSED SURFACE market on the profile
approved drawing SUPPLIED BY THE CUSTOMERS.
Powder coating cannot be covered in the locking as marked in the figure (1).
If Coating is covered on top, coverage shall not be possible in the bottom as marked in Figure
Coating cannot be covered at the portion indicated in the Figure (3).
Coating coverage as indicated in Figure (4) cannot be assured at the corners.
Coating coverage as indicated in the Figure (5) could be of cloudy coverage only (25-40 microns).
Coating coverage for symmetrical profile in Figure (6) could be of cloudy coverage only.
B-5) SURFACE APPEARANCE:-
In accordance to qualicoat specification for quality label 15th edition September 01, 2017. The
coating on the significant surface must not have any scratches through to the base metal when
the coating listed below must be visible from a distance of 3 meters, excessive roughness, flow
line, bubbles orange peel effect, inclusion rates , blisters dull spots, pinholes, scratches or
another unacceptable flows, the coating must be even and gloss with good coverage.
In accordance to BS 6496 : 1984
The finish on significant surface shall have no scratches through to the substrate. When the
finish on significant surface is illuminated as described in BS 3900: part D1 at an oblique angle
with normal on corrected vision, no blister, crates, pinholes, or scratches shall be visible. In
qualicoat and BS 6496, BS 3900, the subject on seeding was not addressed in details. During the
process, the seeding on the surface are unavoidable. ALTAISEER ALUMINIUM COMPANY offers
and guarantees best quality standards.
AS FOR SURFACE APPEARANCE AS FOLLOWS.
The coating on the significant surface should not have any scratches visible with it is viewed at
right angle with normal or corrective vision from a distance of 1 meters. The coating on exposed
surface as identified by the customer will be even glossy with good coverage, pin holes, die
lines, orange peel shall not be visible from a distance of 1 meters. During the process, there is a
possible of seeding (crates or bits) developing on the painted material which are unavoidable.
The acceptable standard is 5 to 6 bits / one meter but should not exceed 15 to 20 bits/six meter
length viewed from a distance of one meter at oblique angle.
B-6) SOLVENT TEST:-
The profile are tested for polymerization quality using solvent Acetone, MEK or Xylene.
ACCEPTABLE QUALITY: A slight loss of gloss and no perceptible change.
NOT ACCEPTABLE QUALITY: The coating is dull and can be scratched with a finger nail.
B-7) ADHESION:- ISO-2409
BS 3900 : PART E6
When coated piece or panel is tested using a spacing of 2mm between each of 6 parallel cuts,
the result shall be in accordance with classification “0” of the standard BS 3900 : part E6. (the
edges of the cuts are smooth and none of the squares of the lattice are detached). A piece of
adhesive tape is applied firmly to the cut area & removed rapidly at right angles to the test area, no piece of the finish other than debris from the cutting operation shall be removed from the
surface of the finish.
B-8) BEND TEST (REISTANCE TO CRACKING O BENDING):- ISO-1519
BS 3900: PART E11
When the coated test panel is subjected to bend test, there will be no sign of cracking.
B-9) IMPACE RESISTANCE TEST (FALLING WEIGHT):- ISO-6272-2
BS 3900: PART E3
The test panel is subjected to impact test using cylinder of mass 4.76 Kgs to fall freely through a
height of 37cm, the impact energy of the cylinder is transmitted by a 14.00 mm O/ ground steel
hemisphere to the test panel placed over a 18.0mm O/ die, when the reverse surface of tested
panel is examined, there shall be no cracking of the coating nor any detachment from the
substrate. The falling height varies from paint to paint according to their property requirement
as specified by the supplier.
B-10) ACCEPTANCE CRITERIA FOR POWDER COATING OF CUSTOMER SUPPLIED MATERIAL:-
THE FOLLOWING TYPES OF MATERIAL CAN NOT BE ACCEPTED FOR POWDER COATING
If the length of the profile is more than 6.2 meters and 7.0 meters.
If the height of the profile/ part more than 1.2 meters ad 1.6 meters.
Fabricated material that has no water draining provision.
Metals other than aluminium and steel.
Wet painted material
Arches having wood connector inside
Over coating of light color on dark color profile
Water stains material
Profile or accessories that does not have a hanging provision
Hard anodized material
A. THE QUALITY OF POWDER COATING CAN NOT BE ASSURED FOR THE FOLLOWING TYPE OF MATERIALS.
Striped and de-anodising material
Standing work done on water stain material.
Material with welded joints.
Galvanized steel sheets.
Grinding work done on rough surface material.
NOTE: If TALCO extruded a product, then the criteria are automatically covered under internal standard same as above, more or less and or as appropriate.
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