Before starting a new collision repair job, it’s critical for technicians to understand where to obtain proper repair information and product instructions and how the use – or misuse – of these products can affect the repair’s final outcome and integrity of the vehicle.
"In general, the most common reason for a product failure ties back to the misuse of a product," says Douglas Craig, structural adhesives applications engineering manager & collision repair industry liaison for LORD Corporation. “Simply not reading instructions causes some failures.”
However, the other 90 percent boils down to two factors: Not leveling two-component cartridges before use and not purging enough material in the mixing nozzle before application.
“When a cartridge is filled the A and B sides are not exactly level,” Craig says. “There could also be an air gap at the top of the package.”
Leveling the cartridge
The ratio of Part A to Part B in a two-component cartridge is critical. An unleveled two-component cartridge can throw off the proper ratio. “If you begin using a cartridge without getting everything equalized, you will be off-ratio,” Craig says.
Once it has been equalized, paying careful attention that the proper ratio can be achieved, the mixing nozzle is attached. The nozzle to be used is chosen using a variety of factors, such as length, the material being used, including its chemistry, ideal working temperature, the amount of adhesive being applied per cycle and the number of times the material is being folded back together. Extrude a mixer length of mixed material and dispose of it.
|How to use collision repair adhesives safely|
When working with collision repair adhesives, it is just as important to use proper safety habits as it is to use the correct repair product. Be sure to follow these steps before starting a job with collision repair adhesives:
Practice safe habits: Wear proper safety equipment and keep sparks/flames away from the area.
Skin contact: Wear gloves to avoid product contact with skin to avoid irritation or a skin reaction.
Eye contact: Flush eyes immediately with water if a product gets into your eyes. Contact a physician for follow-up.
Flammability: Most adhesives don’t contain solvents and aren’t flammable, read product literature and Safety Data Sheets (SDS).Common sense: Be mindful of your environment and use common sense. Treat all adhesives with respect.
"However, if we didn't level the cartridge to begin, we will get more of either Part A or Part B," Craig says. "It will coat the inside of the mixer and throw off everything. If you already have more on one side than the other because a material is sticking to the inside wall of the mixer, you may never get on ratio.”
To ensure the cartridge is producing the proper ratio, examine the material as it is coming out of the mixer. It should be a “nice, homogenous mix” without streaks or dark or light spots, he notes.
“If you find you are off ratio, throw away the mixing nozzle and start again,” he says. “That causes the majority of product failures or issues with a product not working properly.”
|When working with two-component adhesives, make sure to level the plungers until both sides dispense evenly. Be sure to dispense a mix tip’s length of adhesive and look for good mixing without any streaks|
Quick doesn’t equal efficiency
As the old adage goes, time is money. So often the mindset that the more quickly a job can be completed, the more jobs can be completed and the more money can be made. However, this doesn’t mean a collision repairer is being efficient and profitable – or doing repairs correctly. Rushing through a job may very well result in the need for a do-over.