[R-390] RTV for sealing, what we used before, the black stuff

[Tisha Hayes]

In old electronics the black stuff was either pitch or bitumen. There is a
difference; pitch is a rendered down product of pine tar and bitumen is a
petrochemical solid left over in refining.

Bitumen is a type of asphalt where pitch is a very baked down version of
rosin.

I buy big cast blocks of pitch to make "fat wood" and fire-starting
supplies for wilderness survival kits that I give away to youth. it is
pretty nasty stuff and a tub of it smells like a tornado that has gone
through a pine forest.

(I learned such fine distinctions after I sent my ex-hubby out to get
charcoal for a cookout. He decided to load up a big bag of coal from the
pile of a nearby power plant and to spend the charcoal money on more
beer... Since he was responsible for fire (you guys like that stuff) it
seemed to take lots of gasoline for him to get the BBQ going. Those were
the worst tasting steaks we ever had! High sulphur coal is not good for
cooking over! It tasted like something that the devil would have at a
cookout.)

If you ever have to remove the pitch or bitumen you can do it either by
heating or the use of solvents. Both have some serious disadvantages, the
combustibility point for both is pretty close to the melting point and you
will end up with a roaring fire if you are not careful (live steam might be
a good way to melt it, but how many of us have pressurized boilers?).
Solvents have issues as well as it will dissolve the lacquer in a
transformer, break down Bakelite or unwind paper caps.

*Ms. Tisha Hayes, AA4HA*
*"*There are many who live in the mountains and behave as if they were in **the
town; they are wasting their time.*
* It is possible to be a solitary in one's mind while living in a crowd;
and it is possible for those who are **solitary to live in the crowd of
their own thoughts.*"*
**-Amma Syncletica of Alexandria**