Substratum is defined as something that underlies or serves as a basis or foundation. A variation of that noun is substrate and commonly refers to material under the paint. A substrate can be plastic, aluminum or any of a variety of steels. When analyzing damage and deciding how to repair it, how do you know what material is under that paint?
A plastic substrate is fairly easy to identify, and repair/replace decisions are based on the damage along with your shop's abilities to repair it. An aluminum substrate is easily checked with a magnet, and repair/replace decisions are made differently than mild steel.
Steel substrates are more complex, and the consequences of poor or wrong repairs can be severe. For example, applying heat to ultra-high-strength steel changes properties of that metal. Made either stronger or weaker, it won't perform as designed in the next accident. This puts lives at greater risk.
Conforming to multiple priorities in design and production, new vehicles continue to evolve. Customers expect their vehicles to be safer, more fuel efficient and more comfortable while manufacturers continue to look for efficiencies and economies in production. In order to meet such goals, there are new types of steels in different configurations and in different areas to make vehicle structures lighter, stronger and safer. You may not know what they are or where they are. Perhaps you discovered that a Volvo rear body panel was made of boron steel after burning up a few regular spot weld drill bits.
We need to know the substrate type well before burning up drill bits. We should know what metal it is at estimate time. This determines repair options. Maybe the substrate can't be straightened. Maybe it can't be sectioned. Maybe it can't be welded. How would you know?
Experience would be an ideal answer, but the chances of working on the same structural part or reinforcement on the exact same year/make/model become less each model year. Even the same model can change part design, reinforcements or metal composition from year to year.
Your estimating system can be helpful in identifying substrates while writing an estimate. The information providers have made much progress in this direction. All three estimating systems show substrate identification on their parts selection screens. For example, CCC's Pathways identifies high-strength steel (HSS), ultra-high-strength steel (UHSS), aluminum (ALU), boron steel (BOR), hydroformed steel (HYD), magnesium (MAG) and sandwiched steel (SAS). UltraMate, Pathways and Audatex on the Web also show these materials on their estimate print.
This information is not necessarily complete on any of the systems. Manufacturer information may not be complete, may change prior to or during production or may not get updated to the information providers. Absence of substrate identification in your estimating system does not positively identify mild steel. Watch for these identifiers when writing your estimate and make repair decisions accordingly. Note that absence of information can require one more identifying step.
Look for collision repair information on individual manufacturer Web sites. Here you can find the latest information on substrate materials as well as repair procedures. There may be fees involved. General Motors information is no charge, Chrysler is a minor one-time fee, and subscription fees for others are coming down. For easy access, www.oem1stop.com has one-click buttons to get to most manufacturers' collision repair Web sites directly.
In years past, specific repair information was nice to have, but we had general repair procedures that would work. Mild steel throughout the vehicle was workable with or without heat as needed. General sectioning procedures applied unless there was the rare caution on a specific model. Multiple layers of reinforcements were unheard of. This has all changed and the stakes of doing something wrong are ever higher.
Specific repair information and specific procedures are more critical now than ever. What is that substrate? Can it be repaired? Can it be sectioned? Look it up.