[PSUBS-MAILIST] concret sub thermal expansion - glass domes

[diagroto@ibague.cetcol.net.co]

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to: personal_submersibles@psubs.org
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concret sub thermal expansion glass domes 

A question was:
concret sub is thermal expansion a problem ?

As Marsee Skidmore explains in this thread at 17 Nov 1998 19:16:54 -0800 

Thermal expansion in steel and concrete is nealy exactly identical. (only this 
makes concret with steel reinforcement possible)
So you need not worry about it in a concrete sub where you don't worry in a 
steel sub.(effect is almost exactly same size)
This is no concret specific problem ALL material has it. Be careful about it if 
you glue 2 different materials (with different expansion coefficient)
together like glass domes with expoxy (unflexible) to a steel ring, or a 
concrete hull. This can bring tension in your dome.
better to have a silicon (flexible) or rubber seat.
I did it this way on my concrete sub - no problem at all during 15 years.


Wilfried Ellmer
(did concret submarine -9m - in 1994 - worked perfectly - )