WIX Archives

Re: Corrosion Issues...

Posted by John Parker on Wed Aug 06, 2003 06:55:05 PM

In reply top Corrosion Issues... posted by Dave Robinson on Wed Aug 06, 2003 05:52:28 AM

: John,
:
: I saw in your post that you have information on saltwater
: & corrosion...do you have any information on fresh water a
: nd shallow wrecks? What are the problems faced when these
: 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 raising
: 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 problem 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 water in general. Fresh water can be corrosive if the PH balance 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 of fresh water for a time before it is worked on- this is largely in an effort to stop the process of corrosion and remove 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 sea and the composition of the sediments it is in contact with here are another problem as the water may be OK but the mud rots the parts it is in contact with or visa versa.

I am no expert on any of this but generally anybody who has been involved will tell you that the sooner you can get a recovered aircraft treated, cleaned and properly dismantled the better the chance of a high quality restoration are with the smallest loss of material. Exposure to air without 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 great recovery often turns to powder in a short period of time. I think this is what is worrying a lot of people about the Brewster Buffalo recovered in the lake a few years back as it is still sitting around.

I will try to get you some whitepapers from a couple of Universities here in Australia that I have read that might be of use to read.

Regards
John P
:
: Cheers
: Dave

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