It is not mandatory
You can purchase a fiberglass patch for a turtle shell at a pet store that sells reptile supplies, an online retailer specializing in turtle supplies, or a hardware store that carries fiberglass repair materials. Be sure to follow the instructions carefully when applying the patch to your turtle's shell.
patch
If it's cracked, it might be made of fiberglass, or plastic. Fiberglass patch or two part epoxy.
The patch will hold better if you remove the existing patch. If you patch over the existing patch, make sure all the edges are sealed off. If you are tired of replacing your vinyl liners, you might want to check out fiberglass as an option. A new fiberglass surface can be applied to your pool, and you will get a much longer life out of it. You can read more at: http://www.advancedpoolcoatings.com
To patch a hole in a moon bounce inflatable, first clean and dry the area around the hole. Apply a vinyl repair patch over the hole following the manufacturer's instructions. Press firmly and ensure the patch adheres completely to seal the hole. Allow time for the patch to set before inflating the moon bounce again.
patch
There was a hole in his trousers, but he got a patch and repaired it.
To repair a crack in fiberglass, you must first sand the area until it is smooth. Then you must apply a patch to the area and bond it with liquid fiberglass. Once it is dry, the patch must be sanded smooth and then finally painted to match.
Cover/fill the hole..
packing tape.
you want to make a hole in a muffler or you want to patch one up. Make a hole you can use a drell patch a hole best use sheet metal and rivets then muffler puddy around that