Melamine vs PU

Two of the most popular transparent/natural wood finishes are melamine and PU(Polyurethane). Melamine and PU are both synthetic hydrocarbon polymers which form a film over the wood surface that is coated, thus laminating it. The purpose of lamination is to preserve the wood by not allowing the moisture of the wood to escape, preventing it from damage from the elements and protecting it from wear and tear from use. Both finishes enhance the aesthetics of the wood by allowing light to refract inside the transparent layer formed by them. Both the finishes have a similar application procedure by spray. So, what is the difference between the two?

The main difference is in the life of the coatings and its resistance to the elements.

PU Finished Door

Melamine was a great improvement over wood polish as a transparent wood finish when it was introduced in the Indian market in the late 80s and the 90s and is popular to date due to its economy. But melamine has its limitations. The film formed by melamine is only moderately resistant to water. It deteriorates when exposed to sunlight. The film easily yellows and looses lustre. The film begins to crack at the wood joints over time.

With the advent of polyurethane (PU) in the late 90s, most of the shortcomings of melamine were covered. PU forms a tougher film than melamine. It is more scratch resistant. It is flexible and does not crack with the movement of the wood joints. It is UV resistant and can be used on woods that are used in exteriors, such as entrance doors and windows. It does not yellow easily and gives a high lustre. The lustre is also retained longer due to its UV resistance.

PU gives clear advantages over melamine as the application procedure remains the same for both and there is no new skill required to apply PU. Thus the work involved takes the same time and effort on part of the applicator.

Consider wood finishing as a one time investment as reworking of wood finishes takes up lot of resources, skill, time and money. Go for the best coating for your expensive teak or other exotic woods as it will not only preserve the wood but also enhance its aesthetics.

Some things to note when applying Melamine or PU

Melamine or melamatt polish as it is popularly known among the painting contractors is usually sprayed over French/hand polished surfaces, which is not the intended procedure of application.

A study of melamine shows that for all intents and purposes, as in PU, was not originally developed as a wood coating. It is a product of innovation and adaptation that these products are used as wood coatings. The adaptation requires a specific application procedure for the product to perform as a wood coating. These application procedures are grossly ignored by applicators and contractors.

A damaged French Polished door

Applicators apply generous coats of French polish and NC Based Sanding sealers as a preparation for the final coating by melamine or PU. They do this as their skill set for colour matching of wood is based on French polish techniques.

The melamine and PU films often fail as the solvents in the French polish and NC sealers are not compatible with solvents used in PU and melamine coatings. Also, the solvents in the French polish applied under transparent coatings are exposed to light and begin to evaporate and cause blisters in the polymer film formed over it.

It is thus highly recommended that application of French polish be avoided when any such coatings are applied. Wood coated by French polish has its own charm and should not be over coated by polymer coatings.

There are much simpler and compatible colour matching techniques for melamine and PU using wood stains, which we shall discuss in another post.

For a huge range of wood finishes visit http://paintnhardware.com/20-wood-finishes

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Why it is worth investing in quality paint for mild steel fabricated structures

Mild steel fabrications such as entrance gates, safety grills, rolling shutters, collapsible gates, sliding doors etc are known and used for their strength amd durability. They take a short time to be fabricated and can be quickly installed.
They however have a high initial cost and are meant to last a lifetime.

Mild steel has an achilles heel though and it is rust and corrosion. Expose to water, sunlight, dust and pollution cause the structure to corrode and loose its strength and its lifespan quickly shortens. The high initial cost comes to no avail.

It is wise thus to preserve the mild steel structure using anti corrosive paints and coatings.

Normal enamels and metal primers available in the market such as redoxide and zinc chromate primers are prepared using alkyd based binders. These binders typically have a lifespan of 1-2 years on exposure to the elements. The binder being the main film forming and barrier forming medium in the paint heavily influences the life of the paint. Due to the  inferior quality binder, the regular enamels begin flaking and chip off in a short span of time, leaving a small area of mild steel exposed. Smaller areas of exposed mild steel corrode much faster and begin to rust. Rust being more voluminous than mild steel causes the paint in the area around the corroded spot to chip off, causing even more rust, snowballing into a much more serious problem.

To save your invested time and money, it is hence worth investing in a good quality coating for your metal structure. It is also worth following best practices while applying the coating.

To coat any mild steel structure, the following is the best coating procedure.

Start off by removing any corrosion or rust using a rust remover and if necessary use a wire brush. Pay special attention to weld joints and corners as these are the most stressed and are prone to rust. Apply a coat of epoxy based metal primer generously over the surface. Zinc phosphate based epoxy primers are the best ones as the zinc phosphate acts as an active rust inhibitor. Allow the primer to fully cure. Fill dents, crevasses and holes using a polyester based putty, commonly known as a body filler. Give ample time for the putty to set. Apply another coat of the zinc phosphate primer. Allow to cure. To finish the coating aesthetically and to build resistance to deterioration of the coating from exposure to UV, apply a polyurethane based enamel as the final coat. Apply 2 coats of the PU coating, typically using spray equipment.

The above treatment will provide an extremely durable finish and a long life to the mild steel structure.

Special care must also be taken to protect parts that are sunken in the ground. 2-3 coats of the epoxy zinc phosphate primer must be applied before installation. The primer coat must not be damaged during the installation.

Thickness of the coatings on parts that are exposed to hand and foot traffic must be built up using an intermediate hi-build coating to resist wear and tear.

For a wide range of industrial paints and paints meant for mild steel, visit our site : www.paintnhardware.com
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Cement Based Powder Tile Grouts Vs Epoxy Tile Grouts

Tile joint fillers also known as grout are traditionally white cement based powders that are used to fill gaps between tiles and other gaps in bathrooms and flooring. It is common practice even today to use white cement dyed with mineral based powder pigments (known commonly as oxide powders) to fill tile joints in bathrooms, flooring and terraces. While this fills the joints, it is not very long lasting. Being a cement based compound, it is not waterproof. It is absorbent and as a result carries moisture, leading to fungal/algal growth. This is what gives that ugly black/green stain to the tile joints. Also being a lime based product, it is not resistant to common cleaning agents such as acids and bathroom cleaners. This leads to erosion of the grout and ultimately water leakages through the joints.

To cover some shortcomings such as quick discolouration and uniform colour matching, many powder based cement grouts are available. These powder based cement grouts don't do much more that the above. They have no great resistance to cleaning agents and also are not waterproof. Some powder grouts do have additives to enable wide-tile-joint filling where normal grouts tend to crack. SBR based additives are also available to enhance the waterproofing capabilities of powder grouts, but they do nothing to enhance the resistance to cleaning agents.

Epoxy grouts cover all the above shortcomings. They work well as waterproof and chemical resistant tile joint fillers. They also work well on wide tile joints. They have a smooth glossy finish and never loose colour.

Epoxy grouts are supplied as 2 part or 3 part packs. They consist mainly of a resin and a hardner. 2 pack epoxies usually have a coloured resin and 3 part epoxies have clear resins and hardners and a third pigmented powder component used as an opaque filler. 2 part epoxies are easier to use in that they are easier to mix and apply. 3 part epoxies are cumbersome to mix and cause some amount of wastage.

Unlike powder grouts which have to be mixed with water to get a paste like consistency to apply. Epoxy grouts are ready to use once all its components are mixed. The mixed epoxy has a pot life of 25-45 minutes. It is prudent to be cautious while deciding on the quantity of material to be mixed. Mix only so much that can be used within its pot life. The immediate tack free time is about 10-15 minutes after application. The excess grout must be cleaned up before about 20 minutes from application. The only drawback for epoxy grouts is that it can leave behind a mess if not cleaned up properly in time. Epoxy grouts are usually applied using spacers between tiles so as to provide larger surface area for the grout to bond to the substrate. Spacers of 3mm minimum are recommended. Epoxy grout needs a dust and moisture free substrate.

Most bathroom leakages can be arrested using epoxy grouts. Epoxy grouts applied in a contrasting colour to the tiles form a beautiful grid pattern that is both modern and minimalist in design.

Epoxy grouts, as discussed above, out-perform on most criteria and are the future in tile laying.

For Commercially available Epoxy Grouts refer to "Bathroom leakage repairs - Waterproofing Tile Joints using Epoxy Grouts".

What is the Difference Between Duco NC Lacquer and PU?

Duco is a brand owned by Akzo Nobel (formerly ICI) and represents a Nitro Cellulose (NC) Based lacquer available in transparent and opaques. NC lacquers were widely used in the automobile industry to finish vehicle bodies to get a tough weather resistant, glossy film with performance far superior to the then prevalent enamels. But there were a few drawbacks to NC. NC Lacquers are highly viscous and take large amounts of thinner to thin to a sprayable consistency. Nitrocellulose on exposure to sunlight deteriorates, loses gloss and turns yellow. It is also notorious to apply on edges and often begin to peel off at the edges. The NC paints needed to be periodically buffed to remove the yellowed top layer. This leads to reduction of the paint film thickness. NC lacquers are also sensitive to ambient temperature and humidity during application. The temperature and humidity are known to adversely affect the gloss of the finish.

With the advent of Polyurethane coatings, NC began losing popularity as the preferred choice for vehicle body painting. PU as polyurethane is popularly known, has far better technical specifications to NC. PU is colour fast in sunlight and does not deteriorate even on prolonged exposure. PU forms a tougher film than NC due to extensive cross-linking introduced in the polymer. PU does not chip or peel off like NC. No buffing is required to maintain colour and gloss. PU can also be applied in a wide range of atmospheric conditions as compared to NC. PU is also easier to tint and match than NC due to the clarity of its binder and lower viscosity. PU can also be tinted to metallic shades. PU is also available in matt finishes.

Both NC and PU are used to coat wood and metal. These materials are also in wide use in home decor. PU is now the leading coating in the automotive industry and is fast gaining popularity in the decorative segment as well.

With green standards fast becoming the norm, PU is also available in water based variants that can be used to coat wood. They have a comparable performance to Solvent based PUs and are much easier to apply. They don't require elaborate spray equipment and also do not pose a health hazard as they can be brushed on.

For a wide range of lacquers and coatings, visit our online store.

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How to get that Ultimate, Professional Super Glossy Finish for your Car

Ever wonder how The Fast and The Furious are always riding in beautiful, shiny cars, with that bright bling and showroom car finish?

How do they get that ride to be so damn Glossy!!!!! 

How is that black so Black and that metallic so deep???!!

Well, wonder no more, cause here is a step by step guide to that ultimate race car finish. Get that eye-popping gloss and deep colour by following the guide to the Ultimate Professional Super Glossy Finish for your car.

Be prepared for blood, sweat and elbow grease!

Before we flag off, lets look at why you need to put in those hours on your ride.

When the car leaves the showroom for the very first time and is the pride of your life, you see your dreams reflecting off the hood and into the orbit of your fantasies. Scenes of clouds drifting off the car, over the windscreen and over your head give you that high of flying in the open skies.

Those dream slowly loose their sheen as the clear coat of your car begins to loose its gloss.

The rigors of life begin to take a toll on your car. The mud and dust, hail storms and sunny parking lots, that unruly biker, all give your car's paint a really tough time. You take pity on the poor thing and one Sunday, decide to give it a much deserved bath. You use that shampoo that gives you super soft hair and massage it on to the hood as you would on your head. A generous splash of water and a towel down with a cotton/ semi cotton (or who knows what material) cloth in circular motion will get it dry.

The shampoo just killed its sheen and the cloth just made more swirl marks on the paint. Your showroom finish is long gone.

But... is there no anti-ageing Serum you ask???

We have just the prescription for you.

First off, give your car a nice pressure wash using water. No commercial detergents. Make sure all the mud and grime are washed off. Next, wipe your car using a clean, washed, 100% cotton cloth or a chamnois cloth. Wait for it to completely dry. Now, park the car in shade and wait for it to cool off. Make sure there is plenty of ventilation.

Personal safety first. Wear gloves and a mask before the next steps.

Here is the opportunity to introduce you to the trade secrets of the professional car finishers. That dead clear coat can be brought to life by rubbing, buffing and polishing it. How? you ask... The answer is, using specialty rubbing compounds and finishing waxes.

Rubbing compounds and waxes are available in a number of brands and avatars. After a lot of Indian market research, I have found that the ultimate rubbing compound is Meguiar's Diamond Cut 2.0 and the best wax out there is Meguiar's Hi-Tech Yellow Wax.

How do we use them?

On the cool car surface, apply the rubbing compound (Meguiar's Diamond Cut 2.0 is a liquid) with a microfibre cloth. Using a polisher and a wool pad, buff the surface. The speed setting on the polisher must be medium. Work one area at a time. If you do not have access to a polisher, buffing can be done using the microfiber cloth itself. After the buffing is complete, using the used area of the microfiber cloth, wipe off the dust caused by buffing. You will now have lesser swirl marks on the clear coat than before and an enhanced gloss will have developed.

How to maintain this gloss? The gloss thus developed can be protected using a wax polish.

Meguiar's Hi-Tech Yellow Wax is a Carnauba Wax mixed with other high grade ingredients. It adds richness and depth of colour and provides ultimate high gloss protection to any cleaned and polished paint surface. Shake the bottle well. Apply the wax one section at a time. If you are applying the wax by hand, use a 100% cotton terry cloth or sponge applicator. Use light pressure. Spread the wax evenly over the surface using overlapping strokes to ensure complete coverage. Allow the wax to dry to a haze. Now, wipe off excess with a soft cleaning cloth. Turn to clean side of the cloth for a final wipe.

Your car will now be the envy of your neighbors!

After Care 

• Never use commercial detergents and shampoos on your car. 
• Do not use pressure while wiping the car.
• Always use a soft microfiber or cotton cloth for wiping the car.
• Regular re-waxing will maintain the gloss for a long time.
• Your car will again be your pride and joy!

What is Duco Paint? How is it applied?

Duco is a brand marketed by Imperial Chemical Industries (ICI now merged with Akzo Nobel) under which it sells its popular Automotive paints. The Duco brand represents a range of products meant for auto painting and refinishing. The topcoat or the finish coat available under the brand Duco is a Nitro Cellulose (NC) Lacquer. Due to its wide spread use and popularity, the name "Duco" has been genericized to refer to Nitro Cellulose (NC) Lacquers.

Duco was vastly popular as an automotive finish before the advent of Polyurethane paints. Now a days Duco has found a new life as a high quality finish for interiors and other architectural projects. 

NC Lacquers typically are a clear or coloured wood/metal finish that dry by solvent evaporation and produce a hard, durable finish.  (Read more about Lacquers in general here)

Duco being an NC Lacquer has the following properties :

• Fast Drying
• High Solid content 
• Excellent Water Barrier
• Excellent Self Leveling properties
• Takes very well to buffing to give a high sheen 
• Smooth and Hard finish

 Areas of Application :

• Automobile body
• Plywood and MDF
• Sheet Metal
• MS angles and flats
• Architectural and Industrial metal structures

The different surfaces require different preparations. Let us look at the application methods for each of the surfaces mentioned above.


Application method for Sheet Metal and MS Structures :
Materials Required

• Compressor capable of delivering 30-40 psi pressure consistently.
• A good quality spray gun - preferably HVLP type.
• Safety Equipment - Mask, Glasses, Gloves and Overalls.
• Degreaser solvent
• Degreaser Cloth
• Duco Oil Primer / MRF Etch Primer
• Tak Cloths - to remove sanding dust.
• Duco Primer Surfacer - Grey / White - depending on the top coat colour you choose. For Lighter coloured top coats, use Primer Surfacer White and for darker topcoats, use Primer Surfacer Grey.
• Duco Soft Cut Putty 
• Water Emery (Latex paper backed) of grits 220 and 320
• Sanding block
• Duco NC Lacquer
• Duco Thinner
• Rubbing Compund - 3M 1Step is highly recommended.
• Cotton Waste

Application

• Scrap off any loose particles, dirt and old paint from the metal surface to bare metal.
• If the base metal is galvanized, an etch primer is recommended.
• For bare sheet metal, a coat of Duco Oil Primer thinned with a General Purpose thinner in the ratio 5:1 must be applied and allowed to dry overnight. The Duco Oil Primer has excellent adhesion, corrosion resistance and is air drying.
• Apply 2 coats of Duco Primer Surfacer (PS) thinned with Duco Thinner in the ratio 1:1.5 with a flash off interval of 15 minutes between coats.
• Rectify any minor dents and scratches using Duco Soft Cut Putty and a putty knife.
• Wet sand with water emery of grit 220 followed by 320 to level any imperfections.
• Apply a coat of Primer Surfacer on the puttied areas.
• Choose a colour!
• Apply 2 coats of Duco NC Lacquer thinned with Duco Thinner in the ratio 1:2 of the selected colour. Allow flash off interval of 15 minutes between coats.
• Leave to dry overnight.
• Wet sand flat (remove gloss) carefully with emery grits 600/800and apply one mist coat thinned 1:3 with Duco Thinner.
• Allow to dry overnight and polish the surface using 3M 1Step Rubbing compound. 
• For a higher gloss polish use 3M Premium Liquid Wax.

Application for wood and MDF surfaces follows the same procedure as above except for priming using Duco Oil Primer. The Duco Primer Surfacer is applied directly onto the wooden surface.

The finish thus obtained is long lasting and durable.

Duco has the following limitations :

• Requires elaborate equipment to apply - compressor and spray guns are the basic requirements.
• Colour stability on exposure to sunlight is average - easily yellows.
• Attention to surface preparation is required before application - needs a skilled workman.
• Duco is sensitive to the atmospheric conditions during application - A change in temperature can affect the finish.
• Being solvent based, it is not environmentally friendly and precautions must be taken against the health hazards during application. At minimum a respirator mask, gloves and glasses are required. Body overalls are highly recommended. An exhaust system must be in place to extract the solvent flashing off the surface.

 A range of Duco Products is available for delivery across India @ paintnhardware.com

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A Study of Paint Rollers

Introduction to Paint Rollers - A brief history of how the paint roller evolved in India

 

Micro fiber Roller - European Handle

The evolution of the roller has followed the path of evolution of paint in India. Not too closely though. There have been times when the paint technology was far ahead and the roller lagged far behind. As time progressed and paint graduated from lime wash to distempers and emulsions, the transition of brush to roller was a slow one. This was partly due to unavailability of certain roller products and technologies but majorly due to habits of painters and their reluctance to invest in their trade. Painters were usually part time. The finish of emulsions were not up to the mark due to the use of brushes. To counter this, painters began using cheap foam rollers on wet paint after brush application. The finish was better but still not satisfactory and the paint jobs took longer to complete. This system worked for many years until painters began experiencing problems with application of high sheen emulsions. Around the same time, painters also began facing problems with manpower. The modern cloth roller thus began finding acceptance and quickly replaced the brush as a tool of application. This roller not only provided uniform deposition of paint but also reduced the time taken to paint. After some initial resistance - again due to the painters habit and reluctance to invest in trade - the cloth roller is widely used today. 

Variety of Rollers

. Cloth Vs Foam - Cloth rollers are mats of woven or knitted fiber pasted onto plastic tubes and mounted on to handles. The pasting is done in a spiral fashion so as not to leave any marks on the painted surface. Foam rollers are pieces of foam, cut in uniform cylindrical shapes and mounted onto handles.

. A wide variety of sizes are also available. Width x Diameter - 2 " x 1", 4" x 1", 6" x 1", 6" x 2", 7" x 2", 8" x 2", 9" x 2".

Polyester Roller - Cage Handle

. A Wide variety of materials area also available in cloth rollers : Polyester, Acrylic, Micro Fibre, Poly Amide, Natural Hair and Blends of the above. The material is either warp knitted or woven.

Criteria to choosing a roller

With so much variety there is often a confusion as to which roller to choose. The following criteria will make the choice objective :

. Foam Vs Cloth :

 Low density foam rollers pick up a large amount of material and splatter paint onto the surface and are not suitable for application of paint. This leads to a lot of wastage. They can only be used to remove excess paint or smoothen unevenly applied paint. High density foam rollers pick up less material and cause less splatter when placed onto the surface to be painted. They can be used to apply paint. The problem with foam rollers is that they tend to break after usage. They are also very difficult to clean, as the material is absorbed into the entire thickness of the foam.

Cloth rollers on the other hand provide uniform paint deposition and splatter free painting. They are easy to clean as paint is absorbed only into the mat of the material which is on an average only about 0.5" in thickness.

. Pile / Nap of a Cloth Roller :

The roller pile is the length of the fiber. The longer the fiber, the more material it can hold. Also a larger pile will help the roller cover larger surface undulations. But a longer fiber also means a rougher finish. Rollers meant for rough surfaces such as rough plastered exterior walls have a larger pile.

. Material of a Cloth Roller :

Polyester is the cheapest material but has low paint pickup.

Acrylic is a bit more expensive and has better paint pickup.

Micro Fibre is a bit higher in cost and has excellent paint pickup.

Polyamide fibre has equivalent paint pickup and cost to micro fiber but has much longer life.

. Woven Vs Knitted

Woven fibers pickup more material than knitted fibers and also deposit material more uniformly.

. Handles - Cage Style Vs European Style

Cage handles are more expensive than european style handles but have better grip on the roller.

. Lint Free Rollers do not leave behind any fiber on the painted surface. These are generally more expensive.

Considering the finish required, the surface being painted and the paint being used, a suitable roller can be chosen using the above criteria.

A variety of paint rollers available in the Indian market can be bought here..

Happy Painting!!