REFLECTOR: Leaking sump float switch

[wurzel at alumni.caltech.edu]

So, I started noticing blue dye down the side of (and on the
floor right underneath) the sump tank.  Turns out fuel is
leaking either through or around the float switch.  D'oh,
the one-day annual condition inspection morphs itself
into a full-on project.

Unfortunately, my float switch isn't screwed into a hard point
as seems to be the standard these days.  I'm not sure if
Rick L rolled his own low fuel sensor, or if Velocity
used to recommend just glassing the switch directly into
the side of the tank, but in any event it is, in fact, just
glassed right into the side and providing a lovely 100LL
aroma to my cabin.

So, I'd like to convert this to a threaded installation.

1) Any ideas on the easiest way to do this?  My current
thought is to remove the current switch while taking as
little of the surrounding material off as possible.  Then,
sand the outside of the sump tank so it's flat in the area
where the switch was.  Next, coat the hard point and the tank
with epoxy and press them together... finally put some glass
over the outside of the hard point as well (making sure not to
get any in the threads!)

2) What do I need to know about fuel and epoxy?  Is there a
particular epoxy I need to use for this application?  Flox?
Micro?  Do I have to put some kind of sealant on the inside
after the epoxy has cured to prevent leaks or deterioration?
I saw some comments in old posts on using a shop vac to draw a
vacuum and suck the epoxy in around things, and that sounds
like a good idea as long as I'm using the right epoxy and it
doesn't dissolve as soon as the fuel hits it.  :-)

Thanks in advance for the help!