Shape your foam tube, cover with wall joint
compound, sand smooth, paint with water
base paint, spray with release agent.
The release agent will ruin the joint
compound if not painted. Allow to dry,
then glass.
When cured, pour gas inside, pull out
the waste.
The inside of the tube will be
smoother than the outside.

Dennis Clark
N4324S

Dennis,

I presumed Ron knew to use Bondo or some other filling material with
release agent after getting the shape prior to glass. I guess I
should have been more clear. Sanding was just to knock off any
residue.

I actually made a quick disconnect aux tank using a foam shape then
Bondo and a release agent which was written up long ago.

Thanks for the clarification.

JP

A lower tech amd less gooey alternative is to wrap the plug with duct
tape, do the layup and excavate the foam with one of those snap off
blade knives fully extended - cut the foam into 1/2 inch squares and
dig it out.

(A bit hard for a fuel tank unless there is a reasonable inspection
panel built into the plan)

John



-- In Q-LIST@..., "Jim Patillo"
<logistics_engineering@m...> wrote:

Dennis,

I presumed Ron knew to use Bondo or some other filling material

with

release agent after getting the shape prior to glass. I guess I
should have been more clear. Sanding was just to knock off any
residue.