The intention of this session
was to initiate a discussion that would stimulate questions and answers and
share ideas concerning media, methods and technical processes related to
mural painting and attempt to identify and speak directly to any particular
areas of concern that the delegates may have been wrestling with. Often we
find that a discussion of this nature seems to raise as many questions as it
answers, due to the multi-fold approaches and methods that artists employ to
solve their on-site problems; however this seems to be part of the process,
and invites continued discussion and debate. Questions were posed and some
answers were supplied by the group at large.
A question was posed concerning what type of materials were called in for
the creation of “3D murals.” The concern seems to be with methods to erect
supports or surfaces to execute murals that are separate from or raised from
the building surface. Among the solutions discussed for this type of
situation was crezone which is a plywood laminate bonded with adhesives that
make it very stable in exterior applications. Traditionally used by sign
painters for outdoor signage, it is available in different thicknesses and
can be cut with a circular saw. It has smooth heavy paper external skin
which gives a good ground for oil based and acrylic media. There are many
different types of laminated wood based products available from the building
industry, some with resin or synthetic surface treatment that are designed
for exterior cladding use and would lend themselves to erecting mural
panels.
There are a number of critical factors to be considered in the use of such
products, however; firstly laminated products are by definition composed of
a number of layers that have a “sponge-like” effect at the edges of the
panels. Therefore it is of extreme importance to ensure that the edges of
such panels have been carefully and thoroughly sealed with at least one and
preferably two or more coats of a top grade water resistant primer that is
known to be compatible with the panel system you have selected. Sealing the
back of the panels with primer would always be a good method as well.
Employing this procedure will help to prevent the separation of laminations
at the edges of panels, an occurrence that renders a very undesirable
appearance to a mural panel should it occur. Caulking the join lines between
sheets in a mural surface is another important precaution against this type
of damage.
Secondly, it is important to establish the chemical nature of the outer
coating on products that are sold as “pre-primed” or “finished”. Some
coatings are designed to accept paint coatings, whereas some are not . Check
with the distributor or even the manufacturer. Have them send you a spec
sheet on the product and be sure to explain to the supplier the intended use
of the product. Some suppliers are not above selling you a product that is
unsuited for the intended purpose, so it is wise to use a little extra
consideration when obtaining surface building materials. To forestall
disaster, it is very wise to conduct a test of the intended paint media on a
small section of the intended surface material, preferably prior to
installation. Make a thinned solution of the paint media and apply it to the
panel . It should flow smoothly onto the surface and coat evenly and appear
to sink into the surface a little. In the event that the media pools or
beads, or takes on the appearance of water brushed over a waxy surface (the
“wax resist” effect ) then the adhesion of the media is not acceptable. In
this event, check the spec. sheet for an appropriate solvent. Break down the
surface sheen with a light sanding and wipe with an appropriate solvent such
as Varsol, Methyl Hydrate or a well diluted solution of Trisodium Phosphate
(TSP). The effect you want to obtain is to get a matte surface which will
allow thinned coats of paint to bond. Once you have achieved this effect you
may install panels with confidence, but you must apply the same treatment to
the entire surface to be muralized. If you cannot achieve good adhesion with
the test sample, look for a different sheeting material.
Another material that was discussed for these types of application was
Dibond. This is a rubber core sandwiched by aluminum sheets. It is available
in standard sized panels and must be primed prior to painting. Similar
products may be marketed under different trade names. It would have the
advantage of being impervious to cracking and puncturing, but care would
have to be taken to prime with a primer that would adhere sufficiently well
to the aluminum as well as providing an acceptable ground for your top coat
media, whether oil or water based. As with all products, be aware of
manufacturers specs and recommendations for use and follow them closely.
A further product available in Canada under the trade name Hardipanel may be
worthy of consideration for use in such instances. This is a fibre cement
panel composed of Portland cement, sand, cellulose fibres and glue
additives. It is available in 4 foot widths and lengths of 8, 9 and 10 feet.
A 4 x 8 sheet weighs 75lbs. This product comes pre primed and is designed to
accept paint finishes on either a smooth or stucco finish. It is recommended
for 100% acrylic top coats. It is designed to be installed with corrosion
resistant nails, for vertical installation. It can be used like siding in
building construction or can be set into frames for free-standing walls.
Contact James Hardie Building Products Inc. 1-888-JHARDIE (542-7343) for
further information of this product.
Most of the above products would usually be applied to a metal support
structure which had been screwed to the building surface. This support
structure should be constructed by a qualified installer. A wooden support
structure could be employed, but it would have to be primed and sealed
thoroughly to prevent saturation and subsequent transmission of moisture to
the top panels. Again, as with all industrial products, care should be taken
to follow manufacturers recommendations.
A product was discussed for peripheral waterproofing, Atex Novacolor. This
is a water based rubber coating material which is designed for roof
patching. A comprehensive examination of the potential mural site should be
made to observe and detect moisture flow. It may be necessary to take the
step of installing flashing or eaves troughs to divert water flow away from
the surface of an installed mural. Moisture is one of the main causes of
damage to outdoor murals.
The question of alternate materials for indoor large scale mural work was
raised. The use of Bungee Banner was suggested for these applications. This
is a strong canvas anchored and suspended by a bar mechanism and stretched
taut by bungee cords. (a highly elastic tensile cord that clips to the bar
at the edges and pulls the canvas taut). This type of system is widely used
for exterior use where extreme longevity is not required. However, given
that it is sufficiently strong to be erected and operate in wind and weather
suggest that it would be highly permanent in an indoor environment, where
sun and moisture would not cause depredations to the fabric.
A review of the discussion regarding different sorts of elevating mechanisms
follows:
- Scissor lifts:
A type of life truck, electric, gasoline or propane powered, which lifts
by the scissors effect of metal frame arms. Very safe as the weight is
centered over the lifting platform. Not suitable for uneven ground.
Maximum working height on the larger lifts is about fifty or sixty feet.
Easy to learn to operate. Excellent for mural work. There can be an access
gap between the lift’s ground height and the floor, as the work deck of
the lift is about 4-6 feet off the ground in lowered position.
- Scaffold:
Metal frames and plywood covered decks, assembled to different heights.
Can be erected to great heights but especially useful for mural work at
one or two stories. More fatiguing to work than a scissors lift, but
possibly cheaper for long term use and keeps the artist in good shape. Can
be adjusted for use on uneven ground. Anything over three scaffold levels
high must be base plated and jack-screwed to level and requires use of
plastic fencing around the base for safety codes. For a one storey mural,
a single or double cell height on wheels can be rolled along in front of
the mural for a very cost effective work platform solution. A heavy base
frame with automobile wheels and large rubber tires, like a kind of heavy
wagon can be used to erect scaffolding on. This is useful on rough
surfaces, and may be stabilized with outriggers.
- Swing stage:
Typically used by window washers and maintenance crews as well as
muralists, the swing stage is a long narrow platform with safety rails. It
is suspended from metal arms off the roof of the building, by process of
counter weighting, and raised and lowered by electric motors on cables at
either end of the stage. Can be used at skyscraper heights. Good for
height work and safe if set up correctly, but must be installed by a
qualified contractor A mistake in the calculations of the counter
weighting could have disastrous consequences. Relatively easy to learn to
operate from scratch, but more care must be taken in its operation than a
scissor lift. Important to avoid tangling or jamming the cables as they
feed into the electric motors.
Another question raised dealt with the
subject of primers. There is no economy to be gained by using low cost or
economy products in any type of painting but especially with regard to
primers for exterior mural work. The primer is the coat on which all
subsequent treatments depend and as such must be of top quality to ensure a
good life span for the finished work. In short, the use of top quality, top
of the line products is highly recommended for priming applications.
For priming on Masonry or Stucco use the best quality available exterior
latex primer. For situations where there may be holes in pointing or a rough
surface, use a thicker formulation of latex primer known as block filler
intended to fill in holes and cracks in a previously unpainted surface but
may be used over old paint as well. For full treatment use a coat of block
filler then a coat of regular primer. One of the brands of block fuller that
was mentioned was Polycrack (#1 latex or #3 Alkyd). Some of the
manufacturers whose products may be relied upon for quality are Pratt and
Lambert, Pittsburgh Paints, Para, Benjamin Moore. For applications where
stain coverage is required Zinsser Bullseye 1 2 3 is a high hide primer
sealer that will cover fire damage, staining, and resists bleed through to
provide an even topcoat over an uneven base and is a useful product.
Pittsburgh Paints will sometimes send a scientist on site, on request, to
advise appropriate materials, and will willingly provide a catalogue and
material safety data sheet.
The question of sealer (clear) coats over finished murals as a preservative
device was raised. The use of sealers can prove problematic. In the event
that the decision is taken to employ a sealer coat, it must be done with the
strict knowledge that the paint media and sealer coat are chemically
compatible. Check material data sheets or with manufacturers to determine
this information. Sealers tend to be highly non porous which can prove
detrimental over surfaces, especially brick where moisture transfer is
organic to the site. Sealers may change colour over time with a detrimental
effect. Some acrylic varnishes are being manufactured which may prove highly
compatible with acrylic painted murals. Check with Binney and Smith who
manufacture Liquitex acrylics for their recommendations on sealers for
exterior mural work. Acrylic varnishes must be applied with great care as
over-brushing or over- rolling a wet application of clear coat can produce a
milky or grainy effect in the finish which has an undesirable appearance
when dry. If compatible and applied carefully sealers may add some life span
to a finished piece, however, when in doubt avoid an extra coating over your
paint system which may fail.
In order to get the best life span out of exterior mural work, always employ
the following maxim: “sight selection is absolutely critical to the life
span and general success of the mural project”. Check the composition of the
wall in question for efflorescence or signs of conspicuous moisture passage
or damage. Look for a very dry inert site for best results and remember that
a south or east facing site may be warmer to work on than a north or west
exposure, but may exhibit fading comparatively sooner. Murals are more
visually effective in shade than in direct sunlight, especially if there is
a surface texture like brick pointing or stucco. When in doubt about the
physical suitability of a site, consider other sites.
Finally, some of the paint media that were mentioned as tried and tested in
mural application included but are not limited to: Stevenson (acrylic) Nova
(acrylic) Golden, and Liquitex. The above mentioned materials are marketed
as artists material and generally have high viscosity and good light
fastness and mixing capabilities. Many artists paint murals with commercial
latex paints, which are generally lower viscosity and may not mix as readily
as pure pigment to obtain true shades, due to the admission of tertiary
tones into the colour bases. This is not a problem where flat “line and
tone” style of mural is desired and colour matches can be taken from
manufacturers color chips. If a “palette mixing” style of mural is required
where custom shades are mixed on site to render a painterly artwork
following a maquette, then artist materials are probably a better choice.
Commercial latex is generally used for spray applications, but the requisite
thinning of media (and resultant loss of integrity to the binder in the
paint) generally tends to preclude the use of spray technique for long term
on-site murals.
Sady Ducros: An artist with a strong affinity for working with youth and the
community, Sady has completed numerous outdoor murals and community art
projects, as well as doing commercial murals. In the summer of 2001 Sady
worked with Mural Routes as the Youth Coordinator for two murals on Kingston
Road and also traveled to Sudbury where he coordinated a youth mural
entitled Respect for Myths and Mirrors.
John Hood is an accomplished mural artist with numerous outdoor murals to
his credit, John’s work can been seen across Ontario in towns such as
Athens, Collingwood, Fort Frances, Kenora, Toronto and Welland, John has
been affiliated with Mural Routes from its inception and as an ex-officio
member of the board of directors, he continues to provide advice and
assistance to Mural Routes. |
