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peakpoet

A New Idea(?) Cardboard Mold (image intensive)

peakpoet
19 years ago

I guess I should preface this by saying that my balcony has become way too crowded. I'm now on a mission to make large planters to enable me to move a lot of the big plants off the balcony.

I've grown tired of trying to find large, stable and suitably shaped objects with which to make molds for large planters. And even more tired of struggling to release the planters from the molds after I've casted!

So here's my idea. I decided to make the mold out of cardboard, which is readily available where I work.

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Don't laugh, darn it! I'm just starting.

The planter form is 22" at the top and 20" at the bottom (it's upside down).

It's modeled after the large wooden planters they use in local nurserys here to hold mature palm trees. They're made of scrap wood and secured with some sort of metal ribbon.

Next step: wrap with duct tape to strengthen and protect the cardboard from moisture (another muck up I won't go into here).

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I've found it's good to do the bottom after the sides are complete. Remember the bottom is the top here.

Next is to wrap with my favorite - you guessed it! - drywall tape. :-)

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Here's the secret: next I coat it with plaster of paris.

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The POP is cheap, you can quickly slam it on and it dries quickly. Best of all, it really firms up the mold.

After the POP is dry I apply a thin coat of cement. By thin I mean 1/4" at most. The concrete should be quite wet and creamy; like clay, actually.

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This is really a huge planter but at this stage it still weighs less than five pounds!

peak

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