by Douglas Craig, Structural Adhesives Applications Engineering Manager & Collision Repair Industry Liaison
While making plastic repairs with structural adhesives is relatively simple, it is important to understand the product being used and to carefully follow instructions to guarantee optimal results. Profitability comes from doing repairs properly – the first time.
A good rule of thumb is, “Slow down to go faster!” You only want to make a repair once. There is no profit gained in having to redo a repair, especially since the second repair might have to be done free-of-charge to gain customer satisfaction.
Spend the time needed to make the repair properly and be sure to follow the procedures recommended by the adhesive supplier.
Here are some guidelines to follow when using adhesives to guarantee successful plastic repairs:
- Surface preparation – clean the front and back of the surface using the recommended cleaner.
- Backing patch – a backing patch is required if the damage penetrates through the part, such as a bumper cover.
- Sanding – for certain repairs use a sander or sandpaper to prepare the surface for proper adhesion.
- Surface modifier or adhesion promoter – use the recommended surface modifier or adhesion promoter before applying the adhesive.
- Equal mix – two component adhesives require leveling of the plungers. Typically, a bead of adhesive should be dispensed through the mixer before it is applied to the repair area.
- Curing times – follow the manufacturer’s suggested curing times to guarantee optimal repair adhesion. In some instances, parts may require clamping or taping during the curing process, or the use of a heat gun.
- Sanding – follow the manufacturer’s recommended sand times to finish sanding the adhesive.
One of the biggest failure situations that occur in the automotive repair industry is not allowing the proper time for each procedure to reach its finishing point, before moving to the next step. This is where “Slow down to go faster” can really make a difference in the final outcome. Make sure that cleaning solvents and surface modifiers are allowed to dry for the recommended time. Rushing these procedures or steps may result in failure. If the repair adhesive is applied before the proper drying time is reached, the adhesive may not hold and the repair may fail.
Respect written cure times before sanding or other finishing procedures. Do not rely on observation to determine if the adhesive is cured. Follow the recommended curing time before handling or completing work on the repaired part. When using primer or paint, follow the paint manufacturer’s instructions for proper use.
When used properly, some manufacturers’ repair adhesives carry a lifetime warranty. Repairing plastic car parts is both practical and profitable, and will garner customer satisfaction. It is crucial, though, to respect each adhesive manufacturer’s product line to guarantee the best results.
Do not combine repair products from different suppliers; they could be chemically incompatible and compromise the outcome of the repair or cause harm to repair personnel. Use the complete product line of repair products recommended from the repair product manufacturer. Not doing so could negate the warranty.
Always stay within one manufacturer’s process – bottom-to-top – from surface preparation to final finishing.
Adhesives provide a solution to making durable repairs and increase a body shop’s profitability, all while ensuring customer satisfaction.
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