The sign and visual communications industry places demanding and often underestimated demands on bonding technology. From large-format outdoor signs exposed to UV radiation, thermal cycling and wind stress, to precision indoor projection systems assembled from acrylic and aluminum composite panels, the structural and aesthetic performance of a joint of dissimilar materials is often the determining factor in the quality and lifespan of the product.
In signmaking, the quality of construction is judged at the point of bonding. Whether it’s box-type letters, light pillars or high-end Plexiglass stands, the right adhesive ensures that your project will withstand time, weather conditions and mechanical stress.
At Mercouris, we have a wide range of industrial adhesives, and in the following guide we have compiled the adhesives that are widely used in the construction of signs and their applications.
The 3 “Keys” to Successful Welding
1. Structural Strength with Plexus and Permabond 2-Component Adhesives (Methacrylate)
When construction requires strength that replaces screws and rivets, methacrylate technology is the solution.
- Plexus MA8105: The ultimate ally for fast, structural welding of metals (Aluminum, stainless steel, Galvanized metals, etc.) and plastics (acrylic, polycarbonate, ABS, PVC, etc.).
- Permabond TA4204: A structural acrylic adhesive that provides a clear, crystal clear finish. It is the number one choice for assembling acrylic (plexiglass) to aluminum for boxed letters, without casting shadows when illuminated. Also ideal for Plexiglass stands and displays, as it does not create blisters or the phenomenon of “crazing”.
2. Waterproofing & High Aesthetics: Bostik (MS Polymer) & DowSil (Silicone)
MS Polymer technology combines the strength of polyurethane with the durability of silicone, without the unpleasant odors or painting restrictions:
- Bostik MSP 106 Invisible: The completely transparent material, UV resistant, permanently elastic. Ideal for invisible bonding to glass or Plexiglass, where aesthetics are essential.
- Bostik ISR 70-03:The choice for sealing and bonding. UV-resistant, permanently elastic, ideal for sealing joints in illuminated signs, protecting LEDs and internal circuits from moisture.
Silicone offers great elasticity, resistance to temperature, UV radiation and external conditions.
- DowSil AS 7096 N (Transparent Silicone):It is a neutral, soft silicone. It is the ideal solution for bonding LEDs and sensitive plastics, as it does not corrode surfaces, metals and electronics.
3. Precision, Speed and Clarity with Permabond
- Permabond 790: Low viscous, instant cyanoacrylate adhesive that penetrates cracks and small gaps. Ideal for quick “pinch-ups”.
- Permabond 792: Medium viscosity cyanoacrylate instant adhesive, very fast (2-3 seconds). Ideal for bonding rubber profiles and gaskets.
- Permabond 2011: High viscous cyanoacrylate adhesive (Gel) for controlled application (does not “run” at all) and fills gaps.
Applications by Product – Quick Guide
| Product | Main Application in Sign Making | Advantage |
| Plexus MA8105 | High strength bonding of metal to metal and plastic | Replaces screws & welds. Resistance to vibrations & expansions |
| Bostik 106 | Ultra-transparent waterproofing, UV resistance | Absolute clarity, invisible union |
| Bostik ISR 70-03 | Waterproofing of illuminated signs & sealing | Resistance to sun & rain (UV) |
| Permabond TA4204 | Plexiglass assembly with metal for boxed letters | High aesthetics & durability |
| Permabond 790 | Very fast hold on Plexiglass with Plexiglass | Speed in seconds |
Key Takeaways (What to Remember)
- For Metal to Metal: Choose Plexus MA8105 for maximum structural strength.
- For Invisible Joints: Bostik 106 offers a crystal clear result without yellowing.
- For Outdoor Use: Bostik ISR 70-03 is the leading solution for weather sealing.
- For Plexiglass: Permabond TA4204 ensures clarity and prevents cracking.
- For Sensitive Surfaces (LED/Mirrors/Plastics): DowSil AS 7096 N (Neutral action).
Q&A: Professionals’ Questions
Why should I choose Plexus instead of mechanical fastening (screws, rivets)?
Plexus distributes the tension across the entire bonding surface, instead of isolated points (holes), avoiding corrosion and offering a clean aesthetic result without screw heads.
Can I paint over Bostik 70-03 adhesive?
Yes! MS Polymers like 70-03 are fully paintable with most industrial paints, which is not the case with common silicones.
Can I paint over 7096 silicone?
No, silicones are generally not paintable. If your project requires painting the joint, you should choose Bostik 70-03.
Is Bostik 106 suitable for large constructions?
106 is excellent for bonding and sealing where transparency is required. For heavy structural supports of large panels, we recommend combining it with structural materials such as Plexus.
How do I avoid “fogging” on Plexiglass?
Using Permabond TA4204. Common instant adhesives often release fumes that cloud the plastic. TA4204 is designed to maintain the visual clarity of the material.
Why is Permabond TA4204 considered better than a simple instant adhesive for Plexiglass?
Simple instant adhesives create fumes that leave a “haze” around the bond. TA4204 is a structural material that maintains the clarity of the plastic, making the joint almost seamless with the rest of the piece.
In mercouris.gr, we know that every sign is an advertisement not only for your client, but also for your own business. By using the right materials, you ensure that your reputation will remain “stuck” at the top.