[size=medium]The way to repair a cracked coil isn't with silicone sealant.
You should seal it the same way the factory did, here's how to do it.
You'll need a container, like one of those small stainless cups for melted butter.
Some MEK, (methyl ethyl ketone), some ABS plastic, a file, a small paint brush, some 320 grit emery paper,
some 99% alcohol, popcicle stick or wooden chopstick, and maybe an eyedropper.
The area to be repiared has to be clean, and fingerprint / oil free,
Use the emery paper and alcohol to get the area super clean.
Make sure the file is clean and not oily.
File the ABS plastic material untill you have about a half a teaspoon of filings.
Pour about three or four tablespoons of MEK into the container.
little by little add some filings to the MEK while stirring.
You want a consistancy of about twice as thick as water.
Use the small paint brush, or the eyedropper if the crack is in a corner, to brush on
and apply the MEK - ABS mix.
Brush the mix over the crack time and time again untill the crack is completely gone.
You're done. [/size]