Call your local construction company suppliers or a swimming pool building contractor.
Ask where you can get get ZONOLITE vermiculite.
It is very cheap and available almost everywhere.
A 4 cubic foot bag is less than $15.

I got my BIG bag at our local Nursery.
Paws

Um, wasn't Zonolite the insulation that was on a W5 program about the asbestos that was contained in it???? Be careful what you buy!

Marly

Home building stores like HD and Menard's sell it in huge bags for attic insulation , for about $8 , found in the insulation dept of the store.
Plus you could follow one of those roundy-spinning concrete trucks. Some of them use vermiculite and/or perlite also.

I get mine thru a friend that has a nursery.

Thanks everybody for the input! We're about 100 miles from any big stores or nurseries, but I'll keep hunting.

Contact the University of Wisconsin
Tell them you want to make a concrete canoe.:)

Here is a link that might be useful: Vermiculite canoe anyone?.

I just bought a bag of vermiculite at Steins Garden Center in Waukesha 1 1/2 weeks ago. It was 8 quarts for $3.99. Hope that helps.

Aud

If you find ZONOLITE just make sure the bag isn't over 15 years old.:)