Interesting, John.

After my DAR finished the final (and only) inspection of my fresh 235 in
1993, we spent a lot of time discussing care and maintenance of my engine
systems (including fuel), among other things, since he maintained a trainer
fleet that used my type of engine. When he was done, he handed me a short
squawk list - too many/too few threads showing on a bolt or two, replace a
plastic insert nut with an all-steel one, things like that - and in that
list, he noted that a couple of fuel line fittings were showing a little
color right at the thread-to-thread interface. In each case, these were at
the pipe threads, not at the flared junctions.

Also, in each case, all the pipe-thread fittings had been tightened
carefully per the appropriate AC but a couple still showed some seepage. The
DAR recommended that I use Baker Seal on the pipe-threads and suggested
that, if used per the instructions, it would solve the problem. I did so and
it did. I figured that an old-time wrench like him ought to know.

To be sure, I ran a substantial quantity of fuel through the system (about
30 gallons) and out through a filter (three layers of a paper filter
material, liberated from a lab at my work, that caught everything larger
than micron range gunk) and found NO contaminant from the Baker Seal. I did
find a bit of other stuff, mainly a tiny amount of dirt and building debris,
but no sealant.

I guess if you slop the stuff on you could create a problem. Similar to the
anti-seize compound used on the threads of spark plugs, if it's not applied
correctly, e.g., starting a couple of threads back from the end, you've got
a problem - and that stuff is used by every AP I have had work on my engine.
Go figure.

Dan Schaefer