On Sep 7, 5:58 am, wrote:
Hello,

I have a design made out of cardboard that I will be keeping outside
in the elements. I need it to be able to hold rain water inside it,
so I'm wondering if there is any way to water proof it? Here are some
ideas:

1) What If I painted it with an oil based paint?
2) How about using epoxy glue and covering the entire inside?
3) What about coating the inside with Portland Cement?
4) I could coat the inside with tin foil, then use epoxy on the
joints?

Is there a much better idea than these?

Thanks

Well "tin foil" is very expensive, I would use "aluminum foil"
instead. You may look into getting waxed cardboard like
what is used to ship iced seafood products. There are also
polyethylene coated cardboard containers available. One
thing I have used to waterproof speaker cones which are
essentially a type of cardboard is a polyurethane spray
produced for protecting circuit boards from moisture. You
can get it from an electronic supply house. A company
called Techspray http://www.techspray.com/ makes
several types of coatings including one made from Acrylic
which may be the least expensive.

[8~{} Uncle Monster