Description
Weld-On 40 (SCIGRIP 40) is a two-component, clear, reactive acrylic adhesive specifically formulated for bonding, fabricating, and casting acrylics and polycarbonates. Unlike solvent cements (which evaporate to fuse parts), Weld-On 40 is a polymerizing resin that fills gaps, cures to a crystal-clear finish, and offers superior structural strength. Its self-leveling, low-viscosity consistency makes it the industry standard for “museum-quality” joints, laminating thick acrylic sheets, and creating seamless bonds in acrylic furniture and high-end displays. (Both parts A & B are included in each container kit size)
Weld-On 40 is widely known as a “Museum Quality” cement. It is optimized for optical clarity and UV stability in clear plastics. It lacks the elastomeric tougheners and adhesion promoters found in structural adhesives, and therefore not great for metals.
Usage Rule of Thumb:
- Weld-On 40 should be used only for Acrylic-to-Acrylic (or Polycarbonate) where a bubble-free, crystal-clear, solid block look is required.
Key Properties
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Chemistry: Reactive Acrylic (Polymer)
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Color: Clear
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Mix Ratio: 20:1 by volume or weight
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Working Time: 20 minutes (at 73F)
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Fixture Time: 2 hours
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Full Cure: 24 – 72 hours (Heat post-cure recommended for max strength)
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Viscosity: Syrupy / Flowable (Self-leveling)
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Shore Hardness: 85 D (Rigid)
Special and Unique Features
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Optical Clarity: Cures to a crystal-clear, transparent finish that can be polished.
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Gap Filling: Unlike solvent cements, it can bridge gaps and fill voids without shrinking or bubbling (if degassed properly).
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High Strength: Provides a structural bond much stronger than standard solvent welding.
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Weather Resistance: Excellent resistance to yellowing and outdoor aging.
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Machinable: Once cured, the adhesive can be sanded, drilled, and polished just like the acrylic sheet itself.
Typical Bond Strength (Acrylic to Acrylic)
| Curing Condition | 24 Hours (psi) | 1 Week (psi) |
| Room Temperature (73F) | 2,600 | 4,000 |
| Heat Cure (120F) | 4,500 | 5,700 |
| Heat Cure (150F) | 5,900 | 7,000 |
Surface Compatibility
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Acrylic (PMMA) – Cast and Extruded
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Polycarbonate
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Polyester (PETG)
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Butyrate
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PVC (Rigid)
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Not for use on foam or cross-linked polymers.
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Weld-On 40 is a Reactive Casting Acrylic, designed almost exclusively for bonding thermoplastics (Acrylic, Polycarbonate).
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It isnot designed for metals. If you use it on Aluminum or Steel, the bond will likely fail or be very weak compared to the table you provided (which looked like data for a structural methacrylate like Weld-On 45).
Trusted By Industries
From high-end retail displays to architectural signage, Weld-On 46C is the industry standard for:
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Sign & Display: Bonding trim caps to polycarbonate letters and attaching aluminum frames to acrylic panels without visible fasteners.
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Plastic Fabrication: Creating seamless shadow boxes, museum cases, and retail fixtures.
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Transportation: Bonding interior lighting components and aesthetic trim in specialty vehicles.
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General Assembly: Joining metal brackets to plastic housings where a clean, professional finish is required.






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