"Tim Wescott" wrote in message
...
So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.


Tim,

I am not sure exactly, but I might try two different things.

The first would be methylene chloride (Jasco paint remover.)

The second would be either lye or automatic dishwasher soap (cascade).

The latter might be the best choice as it should rinse clean.

I would test this on a couple of older copper pennies. Heat them and
slather some flux on till it sizzles and them let them cool then dunk them
in hot water and the alkaline solution of either the lye or the dishwashing
powder.

You might also do a test on some scrap copper pipe and fittings. This then
can be cut open after cleaning so you can judge how it will work on the
inside of your fuel tank

I use the dishwashing powder to soak nasty cleaning jobs like Pyrex roasting
pans that have that burned on grease that seems to defy all other ordinary
dishwashing attempts, and it works wonders, with no scrubbing needed.

I suspect that your flux residue is a lot like the burned on crud on the
baking dish

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.