Unfortunately, we ran into some snags with our mold removal process. The foam-release agent didn’t work, so the mold bonded to the concrete and it took three days to get it off… At least we didn’t have a male mold!
We need to make a cross-section of our canoe showing the three layers of concrete and two layers of reinforcement for our canoe display, so we did a mini-pour-day. The one section took only about 90 minutes and just a few people; much more efficiently than pouring the actual canoe.
In order to work within our limited budget, we need to get creative with our materials. So instead of throwing out all of our scraps, we reuse them. This year, our bulkhead molds were built out of the cardboard boxes that our reinforcement shipped in. Our cross-section will be made with a section of last year’s canoe mold. We even re-used bulkhead trimmings to re-fill the holes that we popped in our air pockets in those bulkheads. By recycling our materials, we can maximize our small budget to efficiently build our canoe.
Our canoe’s concrete mix is designed to be less dense than water, in order to ensure that it will float (although other factors also influence whether our canoe floats). This year’s mix is less dense than water, but only just. So as an added precaution, we add foam and air pockets (encased in concrete) to the canoe in the bulkheads (at the bow and stern). This way we have some added flotation factor just in case something goes wrong with our mix design!
Yeah, cardboard’s not sandable…
– Erin Khan, Canoe Captain
Trying to de-mold bulkheads…
Our canoe is curing well (had to rethink our humidifying tent concept). Also starting work on the bulkheads tonight…
The male mold is protecting the female mold, which has our baby in it.
~ Erin Khan, Concrete Canoe Co-Captain, summarizing our tactic of using the spare foam pieces that were cut out of the mold (the male mold) to shelter/hide the female mold, which has the canoe we just poured in it, from passers-by while it cures.
Photos by Nick Halsey, Erin Khan, and Lance Hill. Click on an image to see it full size and scroll through them.
