Dick Robertson wrote:
I need to put some flotation in a kayak I'm building. Once installed
it will be difficult to access so it needs to be permanent. Any
suggestions for a simple inexpensive solution?? Something I might pick
up at Home Depot for example??

The two best options for kayaks are bulkheads and flotation bags. There
are very good reasons why the majority of kayak builders use one or the
other.

You DO NOT want sealed air compartments without access hatches of some
sort, as thermal expansion can easily implode or explode a typical kayak
hull. It's imperative that you be able to vent any compartments.
Bulkheads with hatches add a lot of utility to a kayak, anyway.

You don't want to install foam that cannot be readily removed, either.
Water will get in between it and the hull and eventually work its way
through the epoxy and into the wood. Float bags can be easily removed to
allow the boat to dry.

It's also important that the boat have adequate floatation. In a typical
sea kayak with bulkheads, ~50% of the volume of the boat is floatation.
The skimpy foam pillars seen in some recreational kayaks provide nowhere
near enough floatation. About all they're good for is to keep the kayak
on the surface, so recovery personnel know roughly where to look for
your body.