Trying to determine what finish could be on the furniture before you paint it. You need to read this.

 

cp-determine-your-finish-article-3

FAQs ON PAINTING FURNITURE

We feel there is a need to explain a little about the
types of finishes found on furniture bought in antique
stores, garage sales, even picked out of someone’s
garbage. In the past, many different finishes were
used to protect wood from the day to day spills and
wear and tear. Before painting your furniture piece,
there are some things to look for and be aware of
before using Cottage Paint products. This will help
your project end with success.
The phrase “No Priming, No Sanding, No
Stripping” refers to surfaces that are CLEAN from
contaminants (such as Wax) they must be Sealed
(already have a varnish or lacquer surface) Sound
(no chipping or pealing surfaces). In cases other than
a vanished or lacquered piece prime before painting
with a suitable primer.
To start off, we have outlined the many traditional
finishes commonly found on old furniture.

FRENCH POLISH
What is it? French Polishing is the name given to the
process of coating wood with a solution of shellac
dissolved in alcohol, using a “pad” made of cotton
instead of with a brush. The alcohol evaporates, leaving
the shellac deposited upon the wood.
French polish finish, can be painted over as long as
it has been degreased and all wax has been
removed. Even certain cleaning products (such as
Pledge) contain chemicals that prevent proper
adherence of paint. We are introducing an excellent
water based cleaner and wax remover that leaves
the surface ready to paint without rinsing with water.
In the case of a very shinny surface, we recommend
using a 00 wire wool to etch the surface before
painting and after cleaning. Where the surface is
blistered you can use our texturing paste to smooth
it out. Holes that were for handles should be filled
with a water based wood filler, not solvent based.

SHELLAC
Shellac contains a very small amount of resin from
insects. The type of shellac used can vary
considerably in quality and colour, from 2-4 lb
shellac and pale orange to dark brown in color.

DANISH OIL
In America there are a number of manufacturers of
‘Danish Oil’ and each product has widely varying
ingredients. They are comprised of many different
combinations of natural and synthetic varnishes and
resins, mineral oil, Tung oil, linseed oil, poppy oil,
cotton oil, sunflower oil, white spirit, naphtha, driers,
anti-skin agents, etc. etc. Danish Oil finish is usually
suitable to paint with Cottage paint when pure, but
due to all the varieties on the market it would be
safer to prime with our clear primer sealer 24 hours
prior to painting after cleaning.

TUNG OIL
Tung oil is derived from the nuts and seeds from the
Tung tree, which is primarily found in China. The
nuts and seeds are harvested and pressed to
release the oil, with each nut having about 20
percent oil content.
Tung oil is added to paints and stains to help them
better adhere to an object during application.
The primary drawback to Tung oil is that it is derived
from tree nuts. For some people with allergies, exposure
to Tung oil can be problematic or deadly. This material
also tends to darken to an amber hue over time, which
might be undesirable in some applications.

LINSEED OIL
Linseed oil comes from the seeds of the flax plant,
which is grown in central Europe and Asia. The
seeds are pressed or ground to release the oil, which
has a natural yellow coloring similar to
vegetable oil.

shellac
Linseed oil is highly combustible and poses a fire risk
to users. It is not as waterproof as Tung oil and does
not penetrate wood as well when applied as a finish.
It also tends to turn yellow over time as it interacts
with oxygen in the air. When painted over may cause
a yellowish huge to bleed through the paint.
TEAK OIL
Teak oil is most commonly used on outdoor
furnishings. Teak oil can also be added to some
stains and solvents to add moisture-resistant
properties. Any oil based product poses a potential
failure when using water based paint. Although it
may adhere, yellowing may occur due to the nature
of oil. We recommend priming these surfaces to
block any deterioration of the paint. Shellac primers
such as BIN are an excellent choice.
WAX STAINS
Wax stains are essentially a ready-made mix of
finishing wax and a colored stain. You can use our
cleaner to help remove the wax to render the piece
paintable again. Where the colour is red we advise
priming the whole piece with a shellac sealer after
cleaning.

STAINS
Colored wood such as cedar, redwood, and
mahogany and in some cases other common
softwoods, can show a condition known as ”
bleeding” or ” staining” from the tannins in the wood.
This can appear shortly after painting or months
later.
KNOTS
These tannins are partially water soluble and
become more soluble in alkaline products such as
water based paints.
There are a number of different blocking primers on
the market depending on the stain or wood tannins
you are covering, It is wise to clearly understand
what your surface needs are so that you can
correctly block the stains from penetrating through
the painted surface. Pine is not block-able.
If your furniture was built between 1910 to 1920, and
is red in color it is most probably “blood-red”
mahogany, which was stained with an aniline
alcohol dye. The dye will bleed through shellac,
lacquer, acrylic and oil. Most priming blockers will
not hold back these types of stains. The best
prevention is to strip and bleach the wood with
peroxide wood bleach which will help to remove the
red stain. Failing that, a coat of shellac followed by a
modified oil primer is the best remedy.
It’s actually worse if you sand or strip the surface if it
is already sealed with a clear coat. Opening the
pores to the grain will allow the stains to resurface
when exposed to any kind of paint, including water
based mineral ones.
Painting directly on top of the varnish, or lacquer is
typically the best solution providing it is clean, sealed
and sound. Always clean the surface with the
Cottage Paint ‘Clean and Prep’ to ensure the
removal of wax contaminants. If not removed,
cracking and discoloration may occur in the paint
surface immediately or at a later date.
In our experience, the previous finish is usually to
blame if an undesirable result occurs, not the Paint
products being applied on top. Our paint has been
formulated to bond to surfaces that are clean, sealed
and sound. As we have stated, preparation and in
some cases priming is the best way to isolate those
causes and get near perfect results every time.
If the paint cracked due to unforeseen
circumstances there is a solution. Using our clear
primer it will bridge cracks if fine in one coat large
cracks in two then paint the original colour and
you’re done.
Cottage Paint is one of the few products on the
market selling responsible furniture renewal systems
to the public. We produce data sheets as well as
provide a help line to assist you with specific
problems. While it is sometimes difficult to identify
reasons why the product application has failed, we
can usually work together to solve the problem.
Understanding these situations are simply
unfortunate and are hard to foresee, will keep the
project enjoyable.
This blog is an ongoing project and we appreciate
any input from personal experiences in the field. We
can publish comments we receive to support
furniture finishing problems and the recommended
solutions.

Advertisements