On Thu, 24 Mar 2005 14:12:54 +0000 (UTC),
(Paul Tomblin) wrote:

In a previous article, Dave said:
Ans , yes, I have seen many examples of this "delamination" of
composiets...

It would be easier to understand or give credence to your points if you
knew how to spell or punctuate.



Agreed, (I hate laptop keyboards!) Fortunately, I am a better with
survey tools than a keyboard.

I see you have a similar problem...

"and tougher inspections that your boats."

(your paragraph below)



....many cause factors, osmosis being the most common, poor
quality control/contamination during layup are others....

Osmosis happens to things immersed in salt water, which hopefully isn't
the case with aircraft rudders. And the "poor quality
control/contamination during layup" are why I specified that these things
would be caught in the initial inspection. Aircraft parts are subject to
a lot more quality control and tougher inspections that your boats.

Osmosis causes problems in salt, brackish and fresh water. If freeze /
thaw cycles are present after ANY moisture penetrates, delamination
will continue, and can cause structural damage in any composite.

Anyway, I suspect you are seeing cosmetic flaws in the gelcoat, not full
on structural failures.

Unfortunately, no. Entire hulls/boats have been condemmed due to this
problem in severe cases. Most are repairable, although repairs are
very costly. Physical inspection can uncover most problems, but the
x-ray equipment tells the whole story...

And the inspection process for high performance racing hulls rivals
the aircraft testing techniques, including full hull x-ray
inspections...

Thanks for your reply..

Dave