Fellow listers,
Bob Rich's post on copper head gaskets reminded me I could use some advice on
annealing, too. When Mike Allison returned my PA engine which he had rebuilt he
included a comment that the external copper pipes should be annealed and
specifically noted that "polished pipes are not annealed!". I Googled
"annealing copper" and must have found the same pages Bob did. However, in
thinking about how I might do what they said (not having oxy-acetylene, only a
propane torch) it occurred to me that "cherry red" would surely be hot enough
to melt the silver solder (or braze - not sure what the factory used) that
holds the brass end fittings on all the external pipes.
So, I tried with the propane and saw an interesting phenomenon - as the pipes
came up to temperature, they started emitting some gas or another which burned
a noticeably different color than initially seen when I was heating the pipes.
Does anyone know if this indicates that I did something harmful to the copper?
I never was able to get a cherry red color with the propane torch but the pipes
were sort of glowing at that point. This is when I again began to wonder about
the brass ends falling off so I stopped heating and water-quenched the pipe
immediately. After the quench, the pipe was just as inflexible as before and
now an ugly sort of burnt copper color - very much in need of polishing (or,
perhaps, painting engine color and just polishing the brass ends).
I'm sure many of you have had experience with copper pipes on MMM engines
(polished or not, any fractures, etc.?) so if anyone has any comments to offer,
suggestions as to whether my remaining pipes should be subjected to any
attempts to anneal them or be left as they are (there are no signs of stress
cracks in them and they won't need to be bent to be installed), or polished,
painted or left "ugly", I'd be very grateful.
By the way, just for the record, (and without intending to raise an old
argument!) even though Mike painted my engine red, I found traces of the green
paint I remember PA engines being painted around the oil sump flange, the oil
pump, the water pump and the studs on the exterior of the block ..... !
TIA,
Lawrie Alexander
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