You really don’t want to “burn” out all the wax - you want to melt
out as much as possible.
A procedure starting with wet flasks will help. This may involve a
separate steamer from the kiln or a removable drip pan.
A big problem in dewaxing is getting the mold as clean as possible
before doing any burning. Steaming does this at a lower temperature.
Steaming helps to keep the wax from adsorbing melted wax into the
Industrial investment (different investment) casters melt out in an
autoclave with high pressure (100 psig) and high temperature steam.
This is expensive and impractical at small sizes.
Without the high pressure you don’t get a high enough temperature to
get almost all the wax.
You do not want to actually burn the wax in the kiln ( as much as
possible). The kiln requires oxygen to burn wax and all the excess
wax consumes the oxygen outside the mold.
The mold surfaces are difficult to get oxygen to as it is. Diffusion
in small passages and spaces is difficult at best.
In addition to this problem electric kilns with exposed elements
rely on the atmosphere being oxidizing for long life.
If you are burning all the wax in the kiln you are spending a lot of
time reducing. This reducing atmosphere removes the protective oxide
from the elements shortening their life with each cycle.
If you need I can dig out some book references. You probably won’t
want to buy these $$$$.