Lesson Plan Industry Sector

Lesson Plan Originally Created By: Ramon Iniguez

How to make a gasket using a ball-peen hammer (updated) by Ramon C. Iniguez

Part of Unit: Fasteners, Gaskets, & Seals

Lesson Plan Overview / Details

Occasionally, technicians are faced with a situation where a job is being held-up because a simple gasket is on back order.  Rather than wait, technicians can make their own gaskets using a sheet of gasket material and a ball-peen hammer.  

Lesson Time

One class period
100 Minutes

Objectives and Goals

  • Using a sheet of gasket material and a ball peen hammer, students will be able to make a gasket for a thermostat housing.
  • Students will be able to replace a thermostat.

Activities in this Lesson

  • When the class is settled, I tell them, “Yesterday we learned the role of the thermostat and how the thermostat works. Today I am going to show you how to make a gasket and replace the thermostat."  I hold up a pair of scissors, a box cutter (utility knife), and a ball peen hammer. Then I ask the students, “Which one of these three tools do you think I am going to use to make a gasket?” Most will pick the scissors and utility knife. I tell them that although scissors and the box cutter work well, I will show them that the ball peen hammer can be just as effective as the scissors and the box cutter to make a gasket.

  • Demonstration Demo / Modeling

    Using a shop vehicle:

    1. With all students wearing PPE properly, explain to the students that before removing the radiator cap or bolts from the thermostat housing, the cooling system needs to be cool to prevent injury.
    2. Demonstrate how to drain enough coolant from the radiator to remove the thermostat with minimal coolant spill.
    3. HAZMAT: Explain where to properly store the coolant drained from the vehicle.
    4. Disconnect the radiator hose and remove the thermostat housing and the thermostat.

    Note: Explain to the students that other components or brackets may need to be removed to gain access to the thermostat on some vehicles.

    1. Scrape off the old gasket material from the thermostat housing and the engine block. Point out that cleanliness is important to a successful job. Also, point out that the gasket scraper can easily scrape skin off of your hand.
    2. With the thermostat housing clean, place a piece of gasket paper over the housing.
    3. Press the gasket around the thermostat housing bolt holds to make an impression of the hole on the gasket.
    4. Use the ball side of a small ball peen hammer to lightly tap the inside perimeter of the hole, the ball of the hammer will cut the gasket as it strikes on the sharp edge of the thermostat housing. Place the bolts through the holes that you just cut to help hold the gasket in place (see P.P).
    5. Using your thumb and fingers, press the gasket against the inside and outside perimeter of the thermostat housing, this will make an impression on the gasket and also aid in holding the gasket material in place.
    6. Now cut the inside part of the gasket using the ball side of the ball peen hammer (see P.P.).
    7. Next, cut the outside part of the gasket using the ball side of the ball peen hammer around tight curves. You may use the face (flat) side of the ball peen hammer on the wider parts of the housing (see P.P.).
    8. Once the gasket is made with no tears on the sealing surface, install gasket, thermostat, and housing back on the vehicle.
    9. Connect the radiator hose and close the radiator drain valve.
    10.  Add proper coolant amount.
    11. If available, attach coolant pressure tester to check for leaks.

    Resources and Materials

    • Power Point [ Download ] How to make a gasket using a ball peen hammer
  • Lab Group Work
    1. Assign students to groups.
    2. Explain to students how you want the lab to flow e.g. where to get the materials, which vehicle to work on, where to place HAZMAT, etc.
    3. Tell students to stop at specific points and have them call you to evaluate their progress and provide guidance.
    4. Even though each group is working on one vehicle, I require each student to make a gasket using the same thermostat housing. They evaluate each other’s gasket and choose which one of their gaskets will be used to install the thermostat.
    5. Have the scissors and box cutter available for unusual situations.
    6. Monitor progress and provide guidence.
  • Lab review Closure

    Class discussion on what they learned from the lab. I tell the student that in the automotive field, time is money and that sometimes technicians need to improvise to get the job done properly.


Assessment Types:
Projects, Demonstrations, Observations,

During the lab, monitor student progress and provide guidance as needed. I have students call me to assess their progress at designated points of the task sequence.

In the overall assessment I am looking for:

  1. Did the student follow procedures for the task?
  2. Did student follow safety procedures and did the student wear PPE properly?
  3. Did student make a gasket that will seal (no tears on sealing surface)?
  4. Did student contribute to the group?