[VAC] Pop Rivet retraction

[Lashway <rlashway@xxxxxxxx>]

  A few days ago in a message about Vulkem I made the statement that pop 
rivets left a hole down the center and thus  advisable  to seal this  
hole to keep moisture from entering.  I was  wisely reminded by another 
list member off line that this is not so.  That the nature of pop rivets 
is  there is   ball at the end of the mandrel (shaft) of the pop rivet 
and, when the rivet gun is activated,  it is pulled into the interior of 
the rivet, thus spreading it out to create the holding power.  At the 
same time this ball plugs and seals the hole.  My original opinion was 
mislead by  my observing the pop rivets used on the interior panels of 
the '56 Bubble A/S I have been rebuilding.  These pop rivets all have  a 
distinct hole in them and do not use/have the "ball" feature. I had not  
really observed how the current pop rivets  functions until I was 
reminded and observed them    today.   There may be some pop rivets out 
there that are same as the ones original used on my unit but they are not 
what you find on the hardware store shelves.

Roy