| Type | | There are two different types of polyurethane polishes, water-based and solvent-based. Both leave a strong protective coat on the wood. PU polish is comparatively expensive compared to Melamine based polish and carpenters prefer this polish as it can give superior shining in shorter time using less labour. The PU polish is available in multiple stains that help getting the desired shade of wood. You can choose from the shades of teak, mahogany finishing, natural veneer style or other shades available. For exterior and interior application, there are different wood stains in the market so make sure you pick the right stain for the application. |
| Raw Material | | A variety of raw materials are used to produce polyurethanes. These include monomers, prepolymers, stabilizers which protect the integrity of the polymer, and colorants. |
| Implementation Raw Material | To apply a PU polish , start by sanding the wood. - FOR best polish results start by sanding the wood with a sandpaper and dust it off. While doing the sandpaper, ask the painter to rub along the grain of wood and not against it.
- Vacuum or wipe the wood to remove all dust and lint from the surface.
- Apply a thin coat of polyurethane and allow it to cure.
- Water-based polyurethane typically takes around one hour to dry, although humidity will increase this time.
- Solvent-based polyurethane needs around four hours to dry.
- Repeat the sanding, cleaning and application step at least three more times.
- For the final application of polyurethane, sand the piece with wet and dry paper.
- After the final coat of polyurethane has dried, buff the wood with a buffing wheel.
- Whether your polyurethane finishes are water- or solvent-based, this process will leave you with a high-gloss finish.
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| Advantages | PU polish can give good finish in a shorter time. - Both water-based and solvent-based polyurethane finishes can provide a beautiful finish in matt, glossy or satin style.
- Water based Polyurethane is the most environmentally friendly finish.
- It is odorless and quick drying.
- It reduces the maintenance requirement in a furniture item as it creates a surface that has excellent resistance to scratches and moisture.
- Water base polyurethane is available in commercial and domestic quality depending on the durability required.
- Solvent-based polyurethane finishes are the older and more established form of finish.
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| Disadvantages | - The main disadvantage with this PU polish is the higher cost of the product.
- In solvent-based, the fumes are generated while the polish is applied so it is important to work in a well-ventilated area and the area will not be usable till the fumes are cleared from the area.
- They can give a slight yellow tone to the wood finish and on extremely light colored wood, it can cause a noticeable color change.
- The PU finish darkens over time.
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| Weather effect | | PU Polish on wood work and furniture protects the wood from all weather. |
| Time interval between TWO coats | | Allow 4-6 hours total, stretched to allow drying time for the finish. |
| Durability | - Polyurethane coatings more resistance to solvent degradation and have good impact resistance.
- These coatings are used on surfaces that require abrasion resistance, flexibility, fast curing, adhesion, and chemical resistance such as bowling alleys and dance floors.
- PU Polish surface is more durable against ultraviolet rays which present in the sun light.
- The ultraviolet radiation is to a great extent absorbed by the Polyurethane coatings and protects the surface from considerable damage.
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| | Type | There are multiple type of polish available for woodwork. French polish and Melamine based polishes are two options. French polish or Spirit polish is very economical and provides good gloss to wood.but it is not that durable and does not resist scratches or stains. It also looses shine quickly.
Melamine-based polish is discussed in this section. It is more expensive than French polish but adds great beauty to the woodwork and resists scratches. The polish is available in multiple stains that help getting the desired shade of wood. You can choose from the shades of teak, mahogany finishing, natural veneer style or other shades available. For exterior and interior application, there are different wood stains in the market so make sure you pick the right stain for the application. |
| Raw Material | | Wood filler/ filling materials, staining, sealing material and top coat as per finish required such as Varnish, Spirit or French polish, Melamine based finish and tools for polishing. |
| Implementation Raw Material | To apply melamine based polish on a surface, remove all dust and dirt from it.
- FOR best polish results start by sanding the wood with a sandpaper and dust it off. While doing the sandpaper, ask the painter to rub along the grain of wood and not against it.
- The cracks and holes should be cleaned of dust and be filled with wood putty.
- The surfaces should be finished smooth with the help of carpenter’s plane.
- For exterior work, a normal dry day should be chosen because exposure to extreme heat, cold or damp atmosphere will spoil the work.
- While applying varnish, care should be taken to avoid forming fume or air bubbles.
- Brushes and containers should be kept clean.
- Once the polish is applied, it should be allowed to dry completely before the next coat of polish is applied.
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| Advantages | - Provides radiant beauty to the wood.
- Helps in protecting the wood by binding the surface.
- Helps to prevent hairline cracks and absorb the effects of scratching and external damage.
- Helps in reducing the transfer of moisture between the wood and the surrounding weather.
- Provides softness and lasting flexibility.
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| Disadvantages | - Become yellowish with age.
- It requires more labour and hard work to achieve a good finish on the furniture.
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| Weather effect | | Polish finish is weak against moisture. Wet weather reduces the life of polish finish. |
| Time interval between TWO coats | | Two coats are recommended at an interval of 6-8 hours between the two coats. |
| Durability | - It dries quicker and becomes harder and more brilliant than oil varnish but cracks and scales off.
- It does not with stand in moist condition.
- Polish finish is generally done on interior surface as there durability on the exterior surface is less in comparison of paint.
- This mainly due to destructive action on the clear finishes by ultraviolet rays present in the sun light.
- Exposure to extreme heat, cold or damp atmosphere will reduce the life of polish finish.
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