Finishes (Timber and Metals) Flashcards
Why do we use finished for
. Increase durability
. Protect from decay
. Improve the look
. Improve the working properties or performance
Types of timber finishes
. Stains . Preservatives . Varnish . Oils . Paints
Timber stains
. Applied to enhance or change the colour of the natural timber
. Applied with a brush
. Does not give any protection
Timber Preservatives
Are applied to wood to help repel water and moisture, and in some cases resist insect attack
Features of Timber Preservatives
- Traditionally brown colours
* Easy to apply with a brush
Timber Varnish
Varnish can achieve a similar finish look to polish, but gives better protection to the surface
• Different types i.e. Modern Polyurethane, acrylic
• Build up in layers, each layer drying before sanding
• Final coat can have a wax applied for a high quality finish
Timber oils
Applied to enhance the natural oils in the wood already
• applied with a cloth
• built up over layers
• Oils soaks into the timber - enhancing its ability to repel moisture without creating a layer on top of the wood
• Needs to be recoated
Timber paints
Give a solid colour finish to a surface of the wood
• Starts with a primer coat to seal wood, undercoat, then layer up the paint
• Rubbed down between each coat with fine glass paper
• Different finishes e.g matte, gloss or silk
Examples of timber paints
- Oil paints - tougher/durable
- Acrylic paints - dry quickly and non toxic
- Applied - Aerosol and roller. Emulsion often more suitable for brush
- Commercial - spray finishes - specialist equipment
Why is it important to sand timber with the grain before applying a finish?
It ensures that the timber has a smooth finish
Process of preparing a piece of timber before applying a stain
- Remove any dust, stickiness, polish, wax, paint, grease or dirt by sanding
- Provide yourself with a clean surface
Differences between water- based finishes and oil based finishes
- Water based finishes provide a clear finish and have a low odour however oil based finishes give an amber glow and give off strong odours
- Recoating with water based finishes takes less time than oil based finishes - water is 2 hours and oil is 5 hours
Process of paint finishing a metal
- All grease and dirt needs to be removed, surfaces need to be smoothed, dents and holes need to be filled
- Primer can be applied
- Add zinc for extra corrosion protection
Advantages of plate finishing a metal
- Wide Variety e.g colour and pain types
* Excellent protector against harsh elements
Disadvantages of plate finishing a metal
- Paints are typically environmentally unfriendly
* More waste when spraying during application