More Information
UNDERSTANDING PAINT
Your choice of paint has a major impact on many things including the appearance of the finished job, the quality of the work, the cost, the lifespan of the job, and the way in which you do the job.
Paints are used for two main reasons:
- Firstly, to protect the surface onto which they are applied. For instance, they provide a seal against air and water which prevents wood from rotting and metal from rusting.
- Secondly, to decorate or provide colour. Paint plays a crucial role in colour schemes and aesthetics.
Paints are sometimes classified as industrial coatings, e.g. those applied to cars and manufactured goods, and decorative paints, e.g. those used to adorn buildings, which we are more interested in.
What are Paints?
Most paints are a mixture of pigments with liquids, binders, and additives.
- Pigments – protect surfaces and add colour.
- Solvents – used to thin the paint and make it more usable.
- Binders – serve to bind the paint to the surface and to help spread it out.
- Additives – mixed in to improve desirable qualities of the paint.
Pigments
There are two types of pigments: prime or base pigments, and extender pigments.
Different types of prime pigments are used for different types of paints (e.g. metal paint, wood paint, etc.) because they provide protection to the material which is being painted.
Pigments also add colour to the paint. Colour pigments are largely derived from metal compounds, many of which are salts. For example, iron oxide produces reds and browns, and titanium oxide produces white. Pigments are in powder form.
The other pigments, known as extenders, are derived from other materials such as mica, clays, and silicas, and they are generally larger particles.
These are cheaper and can be used to partially replace expensive pigments or binders to keep costs down. However, they also enhance the paint’s adhesion.
Prime pigments include iron oxides which are red or yellow, chrome oxides which are green, and titanium dioxide which is white.
Solvents
Solvents are liquids which the other components dissolve into. They include mineral turpentine (oil paints) and water (emulsion).
Solvents reduce the viscosity of paints and so they are also known as thinners. By thinning the paint, solvents make it easier to apply.
Better quality and more expensive paints usually have a higher proportion of solvent liquid, compared to the solids in the mix. As such they commonly need to be dissolved in additional liquid before use. That means additional cost.
Binders
Binders are adhesives that allow paint to stick to the substrate it is being painted onto. A range of binders may be used including oils, resins, or derivatives of cellulose or bitumen.
In modern paints they are mainly polymers (resins). The three most widely used are alkyd polymers, epoxy polymers, and acrylic polymers.
The choice of binder and the quantity used will affect the quality of the final job. Better quality binders create better quality painted surfaces, which are less susceptible to blisters, cracks, or peeling.
- Latex paints use either acrylics, vinyl acrylics or styrene acrylics as binders.
- Oil paints normally use either linseed oil, soya oil or alkyds. Alkyds are created by mixing an oil modified resins mixed with alcohol and acid. They tend to dry much faster than other oils and produce a hard enamel-like surface. Alkyds are used more in artist paints than house paints.
- Additives
Sometimes additives are used as fillers to give the paint body without affecting its properties, e.g. calcium carbonate, but often they are added to enhance its properties such as improving resistance to mould, controlling drying, reducing susceptibility to marking, or making the paint easier to apply.
Types of additives include:
- Dispersing agents – m ake pigments spread more evenly over a surface.
- Preservatives – prevent paint spoiling in storage.
- Anti-mildew agents – deter mildew.
- Rheology agents – improve durability, affect the flow of liquids
- Stabilisers – deter damage to paint from a variety of things (e.g. temperature extremes, UV light).
- Plasticisers – make paints spread more evenly.
- Curing additives – enable paint to dry quicker.
- Co-solvents – improve viscosity.
The following are examples of typical paint mixes:
White emulsion (acrylic) – solvent 44%, pigment 25%, binder 14%, extender 12%, additives 5%.
White gloss (alkyd) – solvent 40%, pigment 30%, binder 25%, additives 5%.
How Paints Work
Now that you have seen what paints are made of, it is easier to determine how they are able to provide a finish on surfaces. When the individual constituents of paints are mixed, the individual powdered pigment particles become coated in the binder in a process called wetting out. Solvent produces the preferred consistency, and additives are then mixed in.
Paints work by the liquid acting as a carrier fluid carrying the other (dissolved) components onto the painted surface. After painting, the carrier fluid then evaporates and leaves behind the solid components as a thin residue which provides a solid film over the surface which was painted.
There are broadly four types of painted surfaces:
- Solvent-based – uses organic solvents such as esters, hydrocarbons, alcohols, or ketones.
- Water-borne – uses water as a solvent.
- High solid – have a higher proportion of solids.
- Powder-coated – powder only.
The first three use a carrier fluid; but powder coating applies the paint without any carrier fluid. Instead the pigments, binders and additives are applied in a powdered form.
Solvent-based paints are what might be called conventional paints. They are very versatile and have been widely used. However, you need a lot of paint to cover a small area and they also emit a high level of volatile organic compounds (VOCs) due to the solvent being highly atomised.
The other types of paints produce fewer VOCs and are therefore better for the health of those using the paints, and the environment in general. One drawback with other types of paints is that they usually require more surface preparation before painting since the paints don’t spread as easily.
FAQ
FREQUENTLY ASKED QUESTIONS
Here is a list of the most often asked FAQ’s.
General
Q. Why should I enrol with the Academy for Distance Learning?
A. Here at ADL, our students are our priority – we treat everyone as a unique individual.
Q. Do I need to buy text books?
A. No, as each module has been written by highly qualified industry professionals. The content of the material is presented in such a way that text books are not required. However, if you require additional reading your tutor will be able to supply a list.
Q. What happens if I have to stop studying for a while? (eg. become sick, go on holidays, have a baby, move house, etc)
A. It’s OK to take a break and start up your study at a later point in time. Just let us know.
Q. Is there an age limit?
A. There is no maximum age limit. We do however, have a minimum age limit of 18 years. Below that age parental consent would be required.
Q. Are your courses up-to date?
A. Our courses are revised and updated on a rotation system.
Q. Do you have a Cancellation policy?
A. Yes. We have a cancellation policy that is fair and equitable. For further details please click here.
Q. Will I have any opportunity to engage with other students?
A. We have a Student Community group based on facebook! If you don’t have a facebook account already, you could make one just for talking with fellow students on the group.
Enrolment
Q. When can I enrol/start?
A. You may enrol and start at any time of the year – it’s all self- paced.
Q. Can I study from anywhere in the world?
A. Our courses are available to anyone, anywhere in the world from the comfort of your own home. The course content is relevant to any country, culture or economy.
Q. How long do I have to complete the course?
A. You complete the course at any time that is convenient for you.
Q. Completing a 100 hour module – how long will it take?
A. For some students a 100 hour module will take approximately to 3- 6 months to complete. Others take less time and some even longer.
Assessment
Q. Assessment – how does it work?
A. For each 100 hour module you are assessed by assignments (at the end of each lesson) and a final one and a half hour exam (or you may elect to complete a Project, instead of sitting the exam) – the choice is yours – you sit for the exam in your own location.
Q. I don’t cope well with exams – what can I do?
A. You may elect to undertake a Project (set by your tutor) instead of sitting the exam. Projects are completed from your home and can usually take a couple of weeks to complete.
Q. If my assignment is not up to standard is there an opportunity to resubmit my work?
A. Yes –
Q. How many assignments do I need to complete for each module?
A. At the end of each lesson, there is an assignment – so if a course has say, 10 lessons, there would be 10 assignments.
Q. I am having difficulty attending workshops/industry meetings, what can be done?
A. If your course requires attendance at workshops, conferences, or industry meetings; alternative arrangements can be made in your country.
Qualifications
Q. What qualification will I receive?
A. For individual modules, you would be awarded a Certificate endorsed by TQUK (Training Qualifications, UK), providing you complete all assignments and the exam. If you just want to complete only the assignments and not sit for the exam or finish a Project, then a Letter of Achievement would be awarded. For more details on qualifications available please click here.
Q. Can I customize my diploma/higher qualification?
A. Not all educational institution’s certificates /diplomas meet everyone’s needs. The opportunity to Design Your Own Diploma at the Academy (subject to our approval) is an added bonus, not found at other colleges. You choose modules that you think will help you in achieving your goal.
Q. What do I get when I complete the course? Will I receive a transcript?
A. At the completion of all courses and providing all assignments and exam requirements have been met, you will receive your Award and a Transcript.
Tutors
Q. Our tutors – who are they?
A. We appoint Tutors and require that they must be currently active in their industry, with at least 5 years’ experience in their chosen profession.
Q. Can I contact my tutor at any time?
A. Yes – you have unlimited access to your tutor via email through our Online Classroom. You can always leave a message with ADL requesting your tutor to contact you. You decide on how much or how little contact you wish to have.
Q. Practical work – How is this done?
A. To find out more about this part of the course please visit the section on How Our Courses Work here.
