Exhaust donut sealing

["Allan Weidenheimer" <allanw@domain.elided>]

For years, my truck has had a problem with the exhaust leaking
where it meets the donuts.  Partially due to the last miffler shop
welding them crooked, but also the sealing surface was not perfect.
Now, I could have had a shop make new ones, but there was no
guarantee those would work better.  So I set about finding a
solution.  First, I cut a round piece of wood (3/4" thick) at a
10 degree angle that fit part way in the donut.  Then put a
1/4" bolt through the center and chuck it in a drill.
Apply valve lapping compound to the sealing surface of the 
pipe, then set the donut in it.  Put the wood disk in the 
donut, and turn the drill on slow.  Periodically, lift everything 
out, apply more compound, etc.  Continue until there is
a nice, smooth, freshly machined surface on the pipe.  Just like
lapping a valve, for anyone that has done it

This procedure, along with welding the pipes so they
meet the manifold straight, seems to have helped 
tremendously.  Just thought some other might be
able to benefit by using this procedure.

Allan Weidenheimer
72 1210 Pickup