BGAS Short Notes

7/27/2019 BGAS Short Notes

1/2

A B C D

Sa 1 ASa1 BSa1 CSa1 DSa1


Sa 2 1/2 ASa2 1/2 BSa2 1/2 CSa2 1/2 DSa2 1/2


A B C DSt2 ASt2 BSt2 CSt2 DSt2St3 ASt3 BSt3 CSt3 DSt3

A B C DF1 AF1 BF1 CF1 DF1

St 2

St 3

Sa 1

Sa 2

Sa 2-1/2

Sa 3

When viewed without megnification, the surfase shall be free from

visible oil, grease, dirt, from poor adhering millscale rust, paint

coating and foreign materials.

As for St2 but the surface shall be treated much more thorouhly to

give a metallic seen easing from the metallic substrate.

Light Blast

Cleaning.

Thorough Blast

Cleaning.

Very thorough Blast

Cleaning.

Blast Cleaning to

Visualy Clean Steel.

When viewed without magnifacation, the surrface shall be free from

visible oil, grease, grit, from poor adhering mill scale, rust, paint

coatintg and foreinmetter.


visible oil, grease, grit, most of the millscale, rust, paint coatintg

and foreinmetter. Any residual contamination shall be firmaly

adhering.

When viewed without magnifacation, the surrface shall be free from visibleoil, grease, grit, most of the millscale, rust, paint coatintg and foreinmetter.

Any remaining traces of contamination shall show only as slight stain in the

form of spots or stripes.


visible oil, grease, grit and shall be free from millscale, rust, paint

coatintgs and foreignmetter. It shall have a uniform metallic colour.

Rust Grade C

Rust Grade D

Steel surface largely covered with adherent millscale but little if any rust.

Steel surface, which has begun to rust and from which the millscale has begun

to flake.

Steel surface on which the millscale has rusted away or from which it can be

scraped but with slight pitting visible under normal vision.Steel surface on which the mill scale has rusted away and on which general

pitting is visible under normal vision.

Thorough hand &

Power tool cleaning

Very thorough hand &

Power tool cleaning

Total

14

Total6

Total

4

Rust Grade A

Rust Grade B

7/27/2019 BGAS Short Notes

2/2

1

2

3

4

5

67

8

9

10

11

12

13

14

15

16

17

18

19

2021

22

23

24

25

26

lligatering Breaks, which are wide and extensice but do not penetrate to the substrate.

Flaking Mateial progressivelly gets brittle with age, cracks and begins to detach.

Cissing

Cracking

Cratering

Bittiness

Mud Cracking

As defined in BS 2015 Glossary of paint and Related Turms.

The presence of the particals of gel flacculated material or foreign matter in the

coating material. Could be partially cured paint, out of shelf life.The solvent from the top coat softens the under laying material and allows it to

pass into and through the layer, Causing discolouration of new applied paint,

Brown for bitumen, Yellow for coal Tars.

Blisters can be filled with Gas, Liquid or Crystals(Popingup the paint film,Farmation like dome shap).

Degradation of a bonder due to discruptive factors in the environment.Caused by inadequate surface preparation. A difference in surface energy

causes local lack of adhesion. A failure of paint form continuous film due to oil

& grease present on the surface

Coating age and differentional expaian (Breaks extending to the

substrate).

Bown shaped depressions. Caused by escaping solvent or Gases. Paint is of

too low a viscosity to flow and fill the depressions also called a pitting, Smalluniform identification to the substrate.

Slightly breaks in the film that does not penetrate to the substratet.

Algae and Mould

occurre nc em ca cure pa n ng as a resu o a a er or o n e

coating b) Water or oil in the substrate b) Improperly farmulated coating

material.

A void, missed OR an uncoated area.

Caused by slovent strength and also lack of observance of stated overcoating

time. Saftening & expansion of a coating by the solvents a newly applied paint.

Similar appearance to a citrus fruit skin. Caused by paint viscosity

problems or by applicator technique.properties of coating material.

Usually due to the internal formation of the surface skin (Topcoat strong

solvent).

The formation of soap by the reaction of a fetty acid ester and and alkali.

Orange Peel

Ropiness

Wrinkling &

Rivelling

Sponification

Fish Eye

Holiday

Lifting

Curtains. Sags.

Runs and Tears

Grinning

Lapping

Bleeding

Blistering

Blushing Flat finish with milky appearance.

Flocculationseparation of constituentsin the Tie & their refusal to be stirred back to gather

again.

COATING FAULTS

Strokes of paint visible after after the paint has dried.

Seeing the underlaying coats through finish coat.

Blooming Loss of glass & milky appearance due to moisture setting on wett paint.

SaggingToo much paint or thinner per coat, insuficient paint body, temrature too low of

failure to completely mix pigment.

It is due to high film built, Over application on very hot surface, fast

drying coating such as Inorganic Zinc-Rish Primers & Vanyl,s.

Chalking

Checking

Caused by over application. remove offending excess material, lightly abrade &

Recoat.

BGAS Short Notes

Documents

Transcript of BGAS Short Notes