Fake Boulders- how to make rocks

I would like to add several bolders around my pond and waterfall. Does anyone here have experience making them? I like the idea of covering forms with spray foam then finishing, but I do not know where to get a large amount of the spray foam. The small cans from HD or Lowes would be costly.

Red Barrel Studio® Woodring Weather Resistant Faux Rock & Reviews

Foam Rubber Small 3 Piece Stunt Rock Set in 2023

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Landscape Boulder - Small Beige, Fake Rocks

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Should You Use Artificial Rocks in Landscaping?

Fake Boulders- how to make rocks

21 FAUX ROCKS ideas faux rock, fake rock, landscaping with rocks

21 FAUX ROCKS ideas faux rock, fake rock, landscaping with rocks

Landscape Rocks & Pebbles for sale in Detroit, Michigan

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