Patch Hardie Board Cement Fiber Board Siding

Old 01-30-19, 08:08 AM
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Patch Hardie Board Cement Fiber Board Siding

Any recommendations to patch up a square hole that was cut around a copper water pipe for hardie board cement fiber board siding?

I patched a golf ball hole in the hardie board before by using foam spray, then cutting it flush and applying bondo over it then painting with sealer primer and exterior paint.

Given that theres a copper pipe in the patch area I'm concerned the foam would expand when shooting it in and end up moving or breaking the copper pipe.

So what else could I use for backing to be able to then bondo over it?
Old 01-30-19, 08:46 AM
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Spray foam won't hurt a pipe.
Old 01-30-19, 08:47 AM
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How big is the hole compared to the pipe? Low expanding foam might be an option.

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