Maybe you've seen those pots in the stores that look very heavy but are in fact very easy to lift? I think this is a great idea, however their prices are still unreasonably high.
Here's one way to make a large lightweight pot that could pass for being made of concrete on casual inspection.
Here's one way to make a large lightweight pot that could pass for being made of concrete on casual inspection.
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I wanted to plant some things and went to get my favorite large pots from the backyard, but look what happened to them! I pondered how to fix them and decided I would just try to make something new.
Well sure, it's a lot less effort to just go buy a pot, but I always wondered if I could mold things out of spray foam insulation, and after a few tries, I found out that I could.
It remains to be seen how long it will hold up to the elements and whether plants will tolerate being in a pot made of polyurethane foam.
Well sure, it's a lot less effort to just go buy a pot, but I always wondered if I could mold things out of spray foam insulation, and after a few tries, I found out that I could.
It remains to be seen how long it will hold up to the elements and whether plants will tolerate being in a pot made of polyurethane foam.
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I was hoping you could comment on a way to reuse the forms. Perhaps a wooden form covered with wax paper or even plastic (you can get big, cheap rolls of plastic), allowing the wax paper/plastic to be destroyed when you remove the forms, but leaving the wooden forms for use again.
In my case, I was hoping to make about a half a dozen of the same mold, which would be a small trough-like planter about two feet long, but only about 6 inches or so high. I can easily make a mold out of wood from hobby store then cover the wood in wax paper/plastic and make about one or so copies every day. In this manner, each copy would be nearly identical.
In any case, thank you for the wonderful idea.
The problem is I don't really want to buy a jillion cans of "great stuff". Is there a way to get this foam stuff more cheaply -- like by the gallon or something?
I think polyurethane foam is a fantastic material, but you're right, there are some precautions that should be taken, particularly the flammability. Take it from one who has found himself knee deep in a pool of flame - do this outside, with no flames anywhere nearby!
For the curing time, before inserting the inner frustrum, try spraying the foam with water, using one of those misting sprayers you use for ferns and such. Just use a little water. This will speed up the curing time. It may make it foam a little more as well. Reacting with the moisture in the air is what makes it behave the way it does.
Incidentally, for those playing at home, make sure the foam you get is polyurethane. There are water based acrylic foams on the market which, while intended as a non-toxic, water based alternative to the polyurethane, actually behave in a completely different way, and would not be suitable for this particular task. Once dried, (it doesn't "cure" as such) it has the consistency of sponge cake.
BTW I'm not criticizing Space Invader (in case any Selleys people are reading ;-). It's advantages are: non-toxic, non-flammable and easy to clean up using water. You'll probably find these things written on the can. That's how you can tell you got the non-polyurethane one.
However you could of course just put the soil in a plant pot inside this pot to avoid this issue.
If you were so inclined you could also embed LED lights, (or anything really) into the pot prior to forming