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Sometimes going back-to-basics can make the difference between a quality repair and a failed repair. When repairing and refinishing electric vehicles (EVs), unintentional damage to the battery can be avoided by taking the proper steps including researching the paint maker technical data sheets (TDS) for optimal clearcoat baking requirements and vehicle maker service information for temperature and time restrictions.
Each paint maker has different recommendations for optimal clearcoat baking applications. Provided in the paint maker TDS are temperature and time ranges. These ranges may be based on booth air temperature or substrate temperature. How do you determine which temperature measuring method to use? How could the baking operation affect your repair? What other resources are available?

When reviewing a paint maker TDS, you may find statements determining how force dry temperatures are measured. Here are a few examples from product-specific TDS:

AkzoNobel:

“Drying times are stated at recommended application method, film thickness, and object temperature. Drying temperatures provided are for metal or object temperature.”
“Drying times are stated at recommended application method, film thickness, and ambient temperature. The dry times stated may increase with insufficient airflow.”
Axalta:

“10-15 minutes x 160°F (71°C) booth temp”
“Drying time at 140°F (60°C) metal temp 20 to 30 minutes”
“Bake 30 min/140°F (60°C) panel temperature…”
BASF:

In product specific TDS, temperatures and time ranges are stated, but how to measure the temperature is not disclosed. We reached out for clarification. Per the BASF Techline (hotline), BASF uses metal temperatures to measure force dry times.
PPG:

“All force dry times are quoted for metal temperature. Additional time must be allowed during force dry to allow metal to reach recommended temperature.”
Sherwin-Williams:

“Do not exceed 150°F surface temperature while baking. Do not exceed 20 minutes total bake time.”
“Bake 10 minutes at 120°F surface temperature”
Each paint maker has different verbiage to state how to measure recommended bake temperatures and times. Different mixing ratios, solvent selection, or additives can change bake recommendations. Be aware some products do not recommend force drying, this can be found in some air dry or speed clear coats.

How could product selection change the repair process for EVs? When researching repair procedures take note of vehicle maker warnings relating to EV battery temperatures. We have gathered these precautions as part of the OEM Hybrid And Electric Vehicle Disable Search. A simple search can provide vehicle maker, vehicle-specific refinish precaution statements along with additional information.

A vehicle maker might recommend a temperature and time not to exceed when baking refinish products to prevent battery damage. The vehicle being repaired may require alternative paint shop scheduling or clearcoat product selection. A shop might prefer to select a different product or mixture which accommodates air drying and having the car refinished at the end of the day to allow enough time for air drying.

Where to look to find more information related to paint maker recommendations or vehicle maker paint precautions? Paint makers offer technical resources including TDS libraries online or built into their color retrieval software, regional technical representatives and easy to use technical hotlines.

Lastly, do not forget to reference vehicle maker repair manuals to confirm refinishing precautions and other precautions pertaining to the repair.

This article first appeared in the I-CAR USA Collision Repair News.