VARNISH

 

Varnish is clear coating of resin and solvent that dries-hardens to transparent film. Today, Varnish is a generic term for Clear Coatings that provide a colourless (transparent) and (mostly) a glossy surface.

5724760157_96a853be80_z

Clear Coatings are required for several reasons, such as to show-up the surface grain, colour, pattern, or protect artwork or craft pieces. The surface to be coated may not always be perfect or decent. So some form of Conditioning of the substrate surfaces is needed before application of a clear coating.

640px-B._Perat,_Vernissage_au_salon,_Paris_1866

The most common problems with surfaces are like:

1.     uneven colour

2.     unsuitable tone

3.     uneven grain or pattern

4.     patchy absorbency

5.     uneven texture

6.     bleeding or soluble constituents

7.     waxy or oily deposits

8.     alkalinity

9.     acidity

10.   galvanic sensitivity

11.   moisture content and transfer

Varnished Wood Chair

Varnished Wood Folding Chair

The word ‘varnish’ comes from Latin ‘vernix’, meaning an odorous resin, Varnish as word comes from Greek ‘Berenice’, which was the ancient name of modern Benghazi in Libya. Perhaps the first varnishes were produced from resins of local trees of Benghazi.

Wooden Decking Paint Wood House Deck Varnish

Varnishes are clear coatings usually made with oils, oleo-resinous substances and alkyds. Varnishes are comparatively slow drying, high bodied finishes and so can be applied by brush, unlike Lacquer or French polish. Varnish types of finishes have thicker film of high gloss, with better wear and tear resistance.

Kat_004 alt

Varnishes are convertible coatings (materials, which after application change into different but permanent substance), so are more stable.

In the past varnishes were made by boiling linseed or tung oil with modified rosins. Later varnishes were produced from oils with maleic or phenolic modified resins. Nowadays air drying varnishes (oxidation & polymerization) are produced from long oil alkyds, where as baking varnishes (heat polymerization) are produced from medium or short oil alkyds. Often amino resins such as urea and melamine formaldehyde are added to produce a very tough, hard wearing, solvent insoluble, alkali resistant, non yellowing and non degrading film.

Magic Letters Deck

High temperature baking varnishes though superior in many respects have limited use so far as wood, paper and such other surfaces are concerned. Theoretically any film forming medium (used for manufacturing paints -coloured coatings) can be used as a clear coating material, but certain film peculiarities and clarity restrict their use. High grade clear coatings could be of polyurethane, epoxy, polyester, PVA, materials.

Advertisements

3 thoughts on “VARNISH

  1. Pingback: LIST of BLOGS on LACQUERS, PAINTS and THINNERS | Interior Design Assist

  2. Pingback: LIST of BLOGS on COLOURS | Interior Design Assist

  3. Pingback: BLOG LINKS for WOOD and WOOD FINISHING | Interior Design Assist

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s