To use plastic glue (specifically liquid plastic cement, as indicated by the brush application method), you get the parts together first, hold them together with a slight gap along the seam, and then touch the brush applicator to the seam. The glue flows into the gap through capillary action, melting the plastic surfaces which then fuse together as the glue evaporates.
Understanding Plastic Model Glue
Plastic model glue, often referred to as plastic cement, isn't actually an adhesive in the traditional sense like wood glue or super glue. Instead, it's a solvent that melts the plastic surface it touches. When two melted plastic surfaces are held together, they fuse into a single piece as the solvent evaporates. This creates a very strong, permanent bond that is essentially welding the plastic.
There are different types, but the method shown in the reference is common for liquid plastic cement.
The Capillary Action Method
Based on the provided reference, a highly effective way to use liquid plastic cement is via capillary action. This technique ensures minimal mess and a strong bond along the entire seam.
Here’s how it works:
- Prepare the Parts: Ensure the parts you want to join are clean and fit together well.
- Join the Parts Dry: According to the reference, the first step is "getting the parts together first." Fit the two pieces you are bonding without applying any glue initially.
- Hold Securely: Hold the parts together firmly. The reference advises holding them "not too tight," suggesting you should "want a little bit of a gap on the seam." This slight gap or joint line is crucial for the next step.
- Apply Glue to Seam: "Then just touch the brush. To the seam." Touch the loaded brush applicator from the plastic cement bottle directly onto the joint line where the two pieces meet.
- Capillary Action: The liquid glue will be pulled into the narrow gap between the parts by capillary action, flowing along the entire length of the seam.
- The Melt and Fuse: As the glue flows into the joint, it slightly melts the plastic on both surfaces.
- Curing: Continue holding the parts together for a few moments as the solvent begins to evaporate and the melted plastic surfaces fuse. The bond will strengthen as the solvent fully evaporates.
Why This Method Works
This method is preferred for many modelers because:
- Less Mess: You apply the glue precisely to the joint line, rather than coating surfaces beforehand.
- Even Coverage: Capillary action pulls the glue along the entire seam, ensuring a consistent melt and bond.
- Strong Bond: The plastic is truly welded together, creating a very durable connection.
Important Considerations
- Ventilation: Plastic cement solvents can be strong. Use in a well-ventilated area.
- Precision: A steady hand is needed to touch the brush only to the seam. Accidental touches on visible surfaces can damage the plastic finish.
- Drying Time: While the initial bond forms quickly, allow sufficient time (hours or even a day) for the glue to fully cure and the plastic to reharden before handling the parts roughly or applying stress.
By following the steps of fitting parts together, holding them securely with a slight gap, and then touching the brush to the seam, you can effectively use liquid plastic cement for strong and clean bonds on your models.
