Seal Balsa before applying epoxy ?
No argument with Ben Diss except...
I have been making a practice of applying 1 coat of 50/50 weak dope and then scuffing the surface fuzz off with #400 w&d. The resulting surface is still "rough" enough for the epoxy to get a first class "key" without the penalty of soakage into the wood.
Savings? Very difficult to determine. But it makes me feel good.