Aluminum Composite Material (Dibond®, E Panel®, Alucobond®, AlumaComp®, etc.)
Aluminum composite material (ACM), popular in the sign painting industry, is comprised of two prepared sheets of aluminum with a solid polyethylene core. It comes in different finishes, with a polyester-based white or clear coating being the most common. Before priming, lightly sand or abrade and degrease the surface.
When painting with any acrylic, oils, watercolors, or dry drawing media, we recommend a commercial bonding primer or gesso as a base coat. Always follow the manufacturer’s recommended preparation.
Oils and Acrylics can be painted directly on this preparation.
For Watercolors and Dry Drawing Media, an additional acrylic ground appropriate for each media should be applied before painting.
Article: Painting on Dibond
Article: Painting with Oils on Non-porous Substrates
Note: Because there are so many types and levels of quality now available, we always recommend testing the adhesion of the primer to the panel whenever working with a new brand. For information on that, please see our Just Paint article: Will It Stick? Simple Adhesion Testing In Your Studio
Would shellac-based primer (BIN) be suitabe for use a s a primer over Dibond–over a polyester factory finish?
Hello John,
While we suspect that the adhesion would be good with the BIN Shellac based primer on the properly prepared polyester coating on Dibond ( sanded and cleaned ), we have not tested it so cannot say for sure. The other factor is that shellac is alkaline sensitive and so can be affected by the alkalinity of water borne acrylics or other alkaline compounds. We have seen that the white pigmented BIN seems to perform well with waterborne acrylic coatings over it, as it is often used as a stain blocker on house paint projects, but we have seen instances of alkaline sensitivity with plain shellac, and with the pigmented shellac ( BIN ) when used with India ink and our OPEN Acrylics. Here are some links to articles we published with some testing:
Waterproof India Inks and Shellac Based Primers: https://justpaint.org/waterproof-india-inks-and-shellac-based-primers/
Open Acrylics, Shellac and SID: https://justpaint.org/open-acrylics-shellac-and-sid/
So, much will also depend on the specific media you plan to use over the BIN. If using our regular Acrylics, then we think it could work. If using India Ink or OPEN Acrylics we do not recommend using shellac based primers. Oil paints are most likely fine. If in doubt, then we recommend using the alkyd type primers or urethane primers we speak to in the article about painting on Dibond.
If ACM panels are being used for an outdoor mural, primed and painted with acrylic paints, is there any need to protect it with a clear coat of any particular product to withstand the elements?
Hello Cynthia,
We do recommend applying a varnish over exterior murals, regardless of the substrate. GOLDEN MSA Varnish with UVLS in Gloss or Satin sheen can be used for this purpose. We recommend first applying an Isolation Coat over the finished mural, allow that to dry for several days, then the MSA diluted 3 parts varnish to 1 part MSA Solvent for brush application.
Here is a link to our Exterior Mural Guide with some varnish information: https://www.goldenpaints.com/technicalinfo/technicalinfo_murals
Here is our Varnishing Resource with product information about MSA with some videos: https://www.goldenpaints.com/technicalinfo/technicalinfo_varnishresources
We hope this gets you started. please email help@goldenpaints.com or call 800-959-6543 with any questions.
Best wishes!