Here are a few suggestions when prepping and painting foamboards:
By Jim Hingst @hingst_jim
Foam core products consist
of an extruded or expanded polystyrene core covered with any one of a number of
different laminates, including paper, polystyrene, wood-fibre veneer and
anodized aluminium.
These foamboard materials
are commonly shaped using a saw, router or steel rule die. It can also be scored and bent and can be
decorated by painting, screen printing or vinyl decoration. For screen printing and painting, water-based
inks and paints are usually the best choice, although other paints and inks
have been used with success.
Prepping & Painting.
Whenever you are painting,
printing or bonding pieces of foam boards, be sure to read the manufacturer’s
directions. All raw materials used in
conjunction with a foam core material should be thoroughly tested prior to any
production run.
Foam boards laminated with
polystyrene can develop a static charge, which attracts dust and dirt like a
magnet. This can be a problem whether you are painting or applying pressure
sensitive vinyl films. Before painting this substrate, boards should be wiped
down with a damp cellulose sponge to clean off the contaminant and to kill the
static charge.
Many foam-board products can
be painted with a variety of paints including sign enamels, and water-based
paints. While the foamed polystyrene core does a fantastic job of resisting
moisture, solvents can melt the foamed polystyrene core as quickly and easily
as cotton candy melts in a child’s mouth. To prevent damage to the core, when
painting these boards, mask off the core of the board with a plastic tape, such
as RTape’s Blue Block Out.
The foamed styrene core will
also deteriorate, if it is exposed to UV light.
If the board will be exposed to sunlight, you will need to finish the
edges with some type of end cap. Painting the edges with a water-based paint
can provide limited UV protection.
To avoid extra work and
potential problems, do your best to keep the substrate clean in storage and
when handling the material. If the surface is free of dirt and scratches,
surface preparation is merely a process of wiping down the board with a clean
rag.
If the surface is dirty or
scratched, you will need to lightly hand sand the surface with a silicon
carbide dry paper 180 grit or finer. If
you decide to paint the edges of the foam board with water based paint, you can
smooth any rough spots using fine grit sandpaper. After sanding the substrate,
wipe the surface down with a tack rag before painting.
A number of different
methods of application can be used to paint foam board, including painting with
brush, roller or spray gun. To seal the surface and ensure good results, boards
should be primed prior to painting.
Spraying the substrate
generally produces a smooth, uniform finish. When the painted or screen printed
area of the sheet exceeds 60%, the sheet can warp. To prevent this from
occurring, painting the opposite side of the sheet is recommended.
The polystyrene core of foam
board products is a thermoplastic material. This means that when the plastic is
subjected to heat is can remelt. Exposing foam boards to temperatures higher
than 165°F for prolonged periods of time is not recommended. For this
reason, force drying a painted or screen printed sheet in a hot
air oven can cause the sheet to warp.
Some foamboards, such as
Gatorplast®, are faced with solid
styrene film on the board’s surfaces. Before painting, wipe the substrate down
with 70% isopropyl alcohol to clean off any surface dust and dirt.
Some paints with strong
solvents are not compatible with polystyrene. If you are using a solvent based
paint, choose one with a mild solvent. In painting on polystyrene, water based paints
are usually a safer choice.
Before painting this
substrate, be sure to test the paint for compatibility. In testing this
material, check for any adverse reaction on the exterior of the surface, as
well as adhesion of the paint to the substrate. Paints should be applied in
light coatings, so that any solvents will flash off. Heavy coatings of paint
can trap solvents, which can inhibit adhesion.
Vinyl Application Videos
Squeegee Technique. Nothing is more basic in vinyl application than the squeegee. But some squeegees work better than others. And there are right ways and wrong ways to use this simple tool. This video clip reviews squeegee selection, squeegee care and squeegee technique. Click to Link
Wet Applications. Dry applications are typically recommended for most vinyl applications. For those exceptions to the rule, this instructional video explains the right way to perform a wet application. Click to Link
Application of Window Graphics. Installing vinyl graphics on glass can be challenging, because the adhesive aggressively grabs onto this high energy surface. Repositioning graphics on window is generally difficult, if not impossible. This instructional video explains how to dry apply window graphics right the first time. It also describes the necessary steps required for surface preparation. Click to Link
Transferring Frosted Window Graphics Films. Because frosted window films are highly textured, transferring cut vinyl graphics can be problematic. This video provides direction in selection of the right application tape and how to apply these films quickly, easily and without problems. Click to Link
3-Step Surface Prep. This instructional video describes how to properly clean the surface of a vehicle before applying pressure sensitive vinyl graphics to a trailer or doing a full wrap of a car or van. This three step surface prep involves detergent washing, solvent cleaning and a final wipe down with IPA. Click to Link
Vinyl Application Over Rivets. Applying vinyl graphics on vehicle surfaces with rivets is challenging for most sign makers. Vinyl failures to these surfaces are all too common. This video demonstrates some tips and procedures, used by professional decal installers, which will make these demanding applications easier and more trouble-free. Click to Link
Vinyl Application to Corrugations. Learn how to apply vinyl graphics to corrugations in a relaxed state. Forcing films into the valleys of corrugations puts too much mechanical stress on the film. Sooner or later, the vinyl will lift or tent in valleys. Click to Link
Applying Air Egress Vinyls. Vinyl films with air egress release liners have almost eliminated bubbles and wrinkles from applied graphics. Air egress release liners with their highly textured surface structure are problematic. Not much will stick to these liners other than the vinyl film. At RTape our best premask solution for air egress liners is a special Conform® tape called 4761RLA. Click to Link
About Jim Hingst: After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.
Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer. Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.
Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for publications, such as Signs Canada, SignCraft, Signs of the Times, Screen Printing, Sign and Digital Graphics and Sign Builder Illustrated. He also posted more than 325 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published. Vinyl Sign Techniques is available at sign supply distributors and at Amazon.
© 2016 Jim Hingst
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