WIX Archives

Re: Corrosion Issues...

Posted by Dave Robinson on Thu Aug 07, 2003 07:05:37 AM

In reply top Re: Corrosion Issues... posted by John Parker on Wed Aug 06, 2003 06:55:05 PM

: : John,
: :
: : I saw in your post that you have information on saltwate
: r
: : & corrosion...do you have any information on fresh water
: a
: : nd shallow wrecks? What are the problems faced when the
: se
: : are recovered (if any). There are numerous recoveries
: of
: : fresh water wrecks and their condition is amazing but I
: h
: : ave yet to come across the issues they faced after raisi
: ng
: : them and during restoration...
:
: Hi Dave
:
: The simple answer is that there is no simple answer!!!!!
:
: Whilst it is true that salt water is much more of a proble
: m than fresh this not the only factor. Corrosion occurs in
: all water and in the air for that matter. The main issue
: other than salt water is the chemical composition of the w
: ater in general. Fresh water can be corrosive if the PH ba
: lance is too acid or alkaline for instance or if the water
: contains corrosive chemicals or minerals. You often hear
: that an aircraft recovered from water is put into a bath o
: f fresh water for a time before it is worked on- this is l
: argely in an effort to stop the process of corrosion and r
: emove any build up of corrosive material.
:
: A couple of other factors involved here are the fact that
: a wreck also rests on the floor of a lake , river or the s
: ea and the composition of the sediments it is in contact w
: ith here are another problem as the water may be OK but th
: e mud rots the parts it is in contact with or visa versa.
:
: I am no expert on any of this but generally anybody who ha
: s been involved will tell you that the sooner you can get
: a recovered aircraft treated, cleaned and properly dismant
: led the better the chance of a high quality restoration ar
: e with the smallest loss of material. Exposure to air with
: out treatment straight out of water hastends the corrosive
: reaction as oxygen accelerates the process. Unfortunately
: this is exactly what happens in countless cases and a gre
: at recovery often turns to powder in a short period of tim
: e. I think this is what is worrying a lot of people about
: the Brewster Buffalo recovered in the lake a few years bac
: k as it is still sitting around.
:
: I will try to get you some whitepapers from a couple of Un
: iversities here in Australia that I have read that might b
: e of use to read.
:
: Regards
: John P
: :
: : Cheers
: : Dave

John,

Although you say you are not an expert do you happen to know what affect a thin coating of oil applied to an airframe will have on the corrosive process? Will this slow it down and buy time for the aircraft?

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