Technical note on Bond It.
Product Information:
Bond it, is a bonding agent, used to bond gypsum plasters on
smooth low suction surfaces and eliminate hacking (making surface rough, by
making impression on to the smooth concrete surface) E.g. Concrete surfaces.
Reason for Introducing Bond it:
Looking at the current scenario of construction market where in
Huge projects with extensive RCC Concrete structures are coming up, market is
shifting from conventional masonry towards Myone shuttering, shear walls.
Hacking of extensive concrete surface becomes quiet time consuming and tedious.
Also adhesion of our plasters to smooth surfaces is always doubt full. In order
to address changing trends and issues of de-bonding we are planning to bring
our own Bond it.
Why at all a Key (grip) is required for application of Gypsum
Plasters on Reinforced Cement Concrete (RCC)
surfaces?
1. Any Concrete surfaces are smooth and slippery.
2. They don’t provide any key (grip) for plasters to adhere to
3. A key (Grip) can be provided in two manners.
1. Hacking – Commonly called as “Tacha” which provides only mechanical
key (Grip)
2.Bonding Agent – Bonding agent provides chemical bonding properties
as well as mechanical bonding to the surface it is coated with.
Pros and Cons of various types of Bonding Methodologies
Hacking Bonding Agent
Hacking
|
Bonding
Agent
|
Mechanical
Bond
|
Chemical Bond
|
Laborious and
Time Consuming
|
Easy and Fast
to apply
|
Adequate hack marks are always
debatable
|
Once coated,
there remains no concern
|
Higher grade
of concrete (Above M-30) difficult to hack after 10 days
|
Can be applied on any surfaces, rough
concrete, honey comb concrete, smooth
concrete,
higher grade of concretes etc.
|
Risk of
debonding, delmaination etc. always persists
|
No risk
involved
|
Fine chipped particles and dust of
concrete
poses a risk of health hazard
|
No health
hazards involved
|
Cheap at cost
- Rs. 1 per sq.ft.
|
Slightly
expensive – Rs. 3 to3.5 per sq.ft.
|
Typical hacked Surface:
Specification for Hacking:
Hack marks should be angular rough impact marks, 50 in no in an
area of 1 Sq Ft. at a depth of ¾ - 1 Inch, clearly exposing the surface
beneath.
Consequences of improper hacking:
- In adequate and improper hacking leads to weak adhesion of plaster on to the RCC surfaces.
- Major portion of RCC. Surfaces are Ceilings, which have large smooth laminar expanse.
- Plaster which adheres to it in a min. thickness of 8 mm and max. thickness ranging between 15 to 22 mm.
- As the ceiling plaster is exposed to gravitational force, (which tends to pull the plaster material down when in wet condition) requires adequate grip, hold to adhere and withstand force of gravity, if that is lacking, plaster may detach itself from the base surface.
- The detached surface which laterally grips adjacent plaster mass, may delaminate itself as a layer of plaster any time without prior notice or deflection seen.
Hence proper firm bonding is most essential
- The headache and pains which one undergoes in repairing and redoing the delaminated surface is beyond explanation, it not only involves cost, time but as well keeps one under a permanent tension of further de lamination in future.
Hence
Bond it:
- Used as a Bonding Agent.
- To apply on all low suction, smooth surfaces before applying gypsum plaster E.g. RCC Ceilings, RCC Shear Walls all surfaces where bonding can be an issue.
- It is a water based emulsion, having pH value within a range of 7 to 9, which makes it neutral non reactive.
- It is non inflammable.
- Eliminates Hacking and ensure strong and firm bond of Gyproc One Coat.
- Gypsum Plaster with substrates.
Substrates
• Low suction and smooth concrete surfaces.
Product Features:
• Ready to apply, not to be mixed or diluted.
• To be applied as a Single Coat.
• Apply with help of a brush (used for
painting) bristles width 4 or 6 Inches.
• Simple paint application.
• Contains fine aggregates to impart better
mechanical bond.
• Bond it is only the bonding agent which
imparts both mechanical and
chemical bond.
a. Mechanical Bond – Imparted by the suspended fine aggregates,
which
are inert, screened on 500 micron sieve, Pure white in color.
b. Chemical Bond – Imparted by dry polymeric film.
• Green in color, easy to identify applied
surfaces.
• One Coat Plaster can be applied any time once
Bond it dries completely on to the surface, approximate time for drying is 24
hours. (Again it would depend on the climatic conditions and location).
• The only Bonding agent specified with One
Coat Plaster.
• Available in 5 Kgs.,10 Kgs. and 20 Kgs. drums.
Coverage:
Approximate Coverage would be 5.0 Sq Mtr.per Kg., depends
Up on background surface and its suction properties.
Application Methodology:
1. Shake & stir thoroughly before use.
2. Single One coat application.
3. Apply evenly all over the surface with even distribution of
fine aggregates.
4. Apply by Paint Brush.
5. Gypsum plaster can be done once surface is dry.
6. Bond it does not require the polymeric film to be tacky during
application.
7. Bond it does not require dilution.
Adhesion Strength (Pull Out strength):
The tensile resistance is tested by help of adhesion test, where
we achieve results of 2.315 KN. (KN – is Kilo Newton).
Caution:
• Wash hands with water after use.
• Keep away from Eye contact, in case of eye contact
wash eye thoroughly with water, if irritation persists kindly consult physician.
• If at all spills on clothes, wash them with
plain water immediately.
GYPROC
ONE COAT ELITE
1. DESCRIPTION
• One coat Elite plaster is white
hemihydrates, gypsum Plaster is used for
Undercoat, finishing coat & levelling.
One coat Elite plaster can be applied over most existing surface
depending upon the suitability of a particular background in relation to
its strength, suction, bonding properties, shrinkage or thermal movement
characteristics, water & soluble salt content. It can applied on RCC surface
with proper hacking & also on brick wall & Block wall. One coat
Elite plaster can be normally applied upto a thickness of approximately 25mm.
2. IDENTIFICATION AND PACKAGING
One coat Elite plaster is packed in
protected bags constructed to an agreed purchasing specification.
One coat Elite plasters are supplied in 25
Kg. HDPE & PP bags & have a shelf life of three months.
To facilitate this, each bag is marked with
the batch no. and the lot no.
The guidance for use and safety
instructions will be printed on the back of
the bag.
Each bag is marked with the words
“Manufactured by Saint Gobain Gyproc
India Ltd” will be printed on the back of the bag.
3. WAREHOUSE AND LOADING
Wooden platform should be used while storing on a floor to avoid
moisture
absorption. Bags should be handled carefully to avoid tearing –
hooks are not
recommended.
5. PRODUCT DISCHARGE SPECIFICATION
When freshly manufactured and packed, One coat Elite plaster is
approved with conformance to specification.Though the limits are given,
non-compliance should not be regarded as necessarily signalling an automatic
rejection criterion. In the case of variation in setting time product
might be put on “QC HOLD “.In the other cases the batch may be processed with modification/changes and approved with deviations.
6. QUALITY CONTROL
SAMPLING FINISHED PRODUCT
Take a bag sample of 25 Kg to allow all the appropriate testing
to be
carried out on the same sample.
TEST METHODS AND TESTING FREQUENCY
Test method Minimum Testing Frequency
Gypsum Purity Loss on Ignition Every two hours.
Coverage Plaster mixing vessel Every two hours.
Combined water Moisture analyser. Every two hours.
Particle size Sieve. Every two hours.
Specific surface Blain’s
apparatus
Every two hours.
Setting time Vicat apparatus Every two hours.
pH
pH meter Every two hours.
NON-COMPLIANCE WITH SPECIFICATION
If any tests show non-compliance with specifications, a further
sample(s) fully representative of all the material in stock will be taken
and tested. If this sample also shows non-compliance, the material will be held
and processed in accordance with the Works Non-Conforming Products Procedure.
Frequency of sampling and testing will be increased until
confidence is restored that the non-conformance was an isolated incident, or
until the source of the non-conformance has been located and corrective action has been taken to remove the cause of the non-conformance
