worthwhile read

[tbro]

http://www.google.com.au/url?sa=t&rct=j ... lZ6l3LLajw

Especially seals , Fluoroelastomer read before you touch these. The pretty blue valve stem seals everyone is using
A Special Caution on Fluoroelastomers –
Fluoroelastomer is a synthetic material
containing fluorine used for gaskets, o-rings
and seals. When used within design
specifications it is completely safe however if
exposed to high temperatures the material
decomposes and one of the by products formed
is hydrofluoric acid. This acid is extremely
corrosive and is almost impossible to remove
especially from human tissue. When inspecting
equipment which has been exposed to high
temperatures check if any gaskets, o rings or
seals have suffered from decomposition which
will appear as charred or black and sticky. DO
NOT under any circumstances touch either the
seal or the area containing the seal until a
substantial cooling period has been allowed. The
affected area should be decontaminated before
undertaking any further work.