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I'm joined here now by Ian McLeod, who's senior conservator at museums
Western Australia. That's right. That's right. Could you tell us just to start
off with Ian, what is it exactly that you do? Well my day job is
running the Shipwreck Museum and the Maritime Museum and occasionally I get
to do real work, which is solving problems of shipwreck artefacts that
wonderful the part. In a museum we don't like artefacts dying on us so sometimes
they call in me as the sort of triage specialist that sort of allow we have a
dead object. Can you bring it back to life and so that's what I do. That's
wonderful. Now your science background is actually in chemistry. Can you tell us a
little bit about that and how that works in this conservation approach? Yeah
well I'm I did my PhD in electrochemistry and so that's that's all
about studying electrons wanting to leap off metals into some oxidizing
medium and how fast it happens. So I've been studying electrons and their love
hate relationship with metals and oxygen since well the early 1970s so I've been
in the game for a while and I'm just beginning to get it. Well that's very
interesting when we first spoke I actually asked how you made the jump from
I guess an academic or scientific background to such an interesting and
challenging position and you told me that there are a few issues with your CV
originally? Yeah I was I was I was told that my CV was so utterly boring that I
would never get a job in academia and so I thought well maybe I shouldn't be an
academic and I was looking for other jobs and one came up just down the road at
the museum in Fremantle which was to look at corrosion of copper on historic
shipwrecks for a year and so about 12 jobs later and 33 years later I'm sort
of running the place. Okay well there's that's a great career path for anyone who's
wanting to take I guess an interesting path forward but on that you could
perhaps then tell us a little bit more about those rivets explain a little bit
more about what actually happened with them? Yeah the thing with metals is
that their structure is very much dependent on composition and the
mechanical stress and the work history of the object and rivets are
absolutely brilliant bits of metallurgy because as you belt the red
hot metal together and it and it tightens and it cools and really pulls the
metal together however anything that's under stress that's the that's the
challenge because so long as you're in an even environment like like a
metallurgist said wonderful but when you get pinpoint stress that's when things
can unzip because if you get a brittle fracture occurring in one of the phases
which the slag is boom at the all of a sudden the force begins to unzip and you
just go pop pop pop pop pop and then so in that case so literally the ship
actually fell to pieces? Well enough of it opened up and I've worked on West
Australia's first colonial steamship the Xantho and the reason why it sank was
that it seems began to open up during the storm and everything's fine until you
just get pushed that teeny little bit too far and then boom you either sink or
fall apart it's the same with people. Okay very true very true now you've
actually done a lot of conservation work with artifacts from the Titanic yeah
that's right. Would you like to take us through a bit of a presentation on some
of the things that you've done? Yeah well why don't why don't we begin and and so
all I'm going to do is just give you a bit of a run-through on some of the
things that I've worked on from the Titanic and a couple of my former
interns Stefan Panek was French more particularly he was Breton and if any of
you know French people they definitely they are not French they're Celtic they
are Breton and Rhonda Wozniak she was from America and they worked with me and
then it was through them that I got my connection with artifacts from the
Titanic because they said hey Ian we've got this stuff that's falling apart
can you come and solve the problem and one one of the things is that as Emily
said when you go down you know 3.8 kilometers a lot of funny things start
happening materials just behave differently under that huge pressure and
so ceramic plates they can get fishes and cracks developing in them and when
you bring them up unless you're very careful if you ever let them dry out
before the salts have got out they fall apart okay and it is a very special
environment down where the Titanic rests yeah because our people say oh well
it's just seawater but at seawater with a difference because when you have 400
atmospheres pressure gases in seawater behave very differently and it's Mr.
carbon dioxide that really undergoes big changes and therefore the whole
carbonate chemistry of seawater fundamentally changes with pressure
okay and you the main issue with the Titanic is you've got the so-called
film-free corrosion in our shallow water wrecks down to about three four hundred
meters calcium carbonate puts a nice protective skin over the metal and so
you get a barrier for the electrons to have to jump through before they get out
to the ever-loving oxygen that just wants to rip electrons out of iron and so
what happens is that with the Titanic doesn't although there's only point to
parts per million oxygen compared with in golf's and Vincent or Spencer golf
don't matter which one you take it's about nine parts per million and so it's
still you know reason amount of corrosion can go there but because there's no
barrier between the metal on the Titanic and the oxygen it goes a lot faster
than you would expect so Titanic is in fact corroding at a much faster rate
than you would normally expect for a shallower wreck at two degrees okay and
you get you get a lot of interesting corrosion products that you haven't been
found minerals but are normally found in in a very different environment and for
example on the on my right of that that screen you've got a view of typical
marine wrecks covered with concretion but on the left you've got a view of HMA
Sydney tomb which is sunk off the WA coast at two thousand four hundred and
eighty meters it is so easy to remember the depth to for you leave out the six
and you got an eight and then but at that depth the sodability of calcium
carbonate is so high you don't get any anything forming no concretion and so the
Sydney is a bit like our own Titanic I mean it's not as good but it's it's
pretty cool and and you can see on on the view of the Sydney that you've got
paint paint is still on the Sydney as more or less as it was when it was sunk
you know nearly 70 years ago and but because of the change in chemistry at
depth I said to make McCarthy before he went on that expedition you will find
their bodies because they'll all be dissolved and it's the same on the
Titanic and so if you want an EK friendly burial just be deposited and if you
in a couple of kilometers of seawater and you will all dissolve in a very
systematic fashion so so what actually does the dissolving because it's quite
interesting as I found researching and we'll see shortly a number of artifacts
that you probably wouldn't expect to find are preserved those depths and human
remains just vanish yeah it's it's it's all due to the way in which calcium
minerals behave under under pressure and as as you go down calcium is one of
those things calcium carbonate that it is but behavior is totally different it's
like the wild child its sodability goes up as the temperature goes down which is
the reverse of normal and the sodability goes up as the pressure goes up
so Titanic had two things going for it in terms of dissolving people it was
really cold and really deep now just on the on the fact that there's no
concretion there to protect the Titanic it is in a big brine solution would it
be possible to perhaps park a ship up on the surface and electro plate it no no
a because even though if you temporarily put a current in it would make the
surface a sufficiently cathodic or sufficiently alkaline to precipitate out
the calcium carbonate as soon as you turned off the current it would just say
bye bye and and go and re-dissolve okay and so you'd need to have a lot of
current going into the ship all the time and as Emily will tell you getting
cables down in an untwisted fashion four kilometers down you're really
pushing it okay and there's a view of a really lovely nickel pot and make that
French of course because they know how to cook and the in in the handle there
was a bronze handle but it corroded in a different way to the nickel and so the
electrochemistry of the different components changes with depth and and
therefore things that appear to be good and stable on the surface can just go
an unzip as you go down and that that's an image of of the whole matrix of the
bronze with copper corrosion products lead impurities and everything in there
but I was able to look at that and work out backwards what had been going on
because metals when they corrode are beautiful things they they leave a
story behind and it's up to us as conservators to come along and say to an
object how are you today and it's just which means thank goodness someone's
come along who understands what I've been going through for the last so tell
me tell them what I've put what I have to put up with and so that's why you
people might say oh it's boring looking at corrosion products but it's like
reading back pulling back the pages of a real book and that's what electro
chemistry does for corroding metals it enables us to tell the story and then
we can put it together and put on exhibitions like down in the South
Australian Maritime Museum which everybody should go and visit yes
absolutely we'll get Emily to point that up in a bit now just just on that
these are all artifacts that we're looking at now that have been recovered
from the Titanic yes how as a conservator have you come across them have
they been farmed out to well that I I came across for example this bit of a
Sydney newspaper from 1911 I was at a meeting with colleagues in
France and at Stefan's lab they had all this rust in crusted newspaper and they
said can you treat this and I said yes and they said well rude words I don't
believe you and so I made up a brew with ammonium citrate and a little bit of
sodium diethionite to get the reaction going you make it sound so simple and and
and I went gently swish swish with the solution and and they said how long will
this take we're going to be here all night and I looked at my watch and I
said the corrosion products will be dissolved in approximately 18 minutes and
after 15 minutes all was dissolved and we ended up with this piece of newspaper
looking like that and the amazing thing Steve was it was a Sydney newspaper the
one fragment that they got me to treat from the Titanic was from a Sydney
newspaper from a year before the shipwreck and it appears to have been
wrapped around some kangaroo skins that one of the passengers was taking to
New York to try and set up an export business Wow so these are the sorts of
stories that we can unravel through conservation yeah yeah and we even found
the blokes glasses and we're able to identify from his medical records in
the prescription that the person to whom the glasses belonged Wow and many of you
may not be familiar with the spittoon there's a spittoon with a white star
lion stamp on it was a genuine product but you know they were for people just
going quietly thawing and it was publicly acceptable to spit into these
receptacles but you see a gap in the edge of the spittoon and that is where
that little bit of this object had been in the mud and the anaerobic bacteria
went into the object so when it was recovered that bit fell out but the
bit that had been in the oxygenated water was fine so even in the small
distance of that much space you can have completely different environments and
so a metal can either live or die and that's that's part of the death of of
an object and one one of the things was that we found these huge accounts of
sulfates as corrosion products now normally you don't get them on a rec
site I thought why and Titanic gave me the answer it's cold and when you go
down to almost zero degrees if you're a sulfate iron normally at room temperature
you'll sit around hi I'm fat sulfate now I'm happy and and if you go to two
degrees you go it's cold and you shrink and you shrink much more than the
chloride so although the analytical concentration is the same the size is
less so more of us fat so thin sulfates can sneak up and a higher effective
concentration causes all these sulfate corrosion products to come on the
Titanic so there is a massive example of just how temperature affects corrosion
and this is a view of some EPNS electroplated nickel silver plates and in
this case the silver there was no no silver sulfide no silver chloride the
silver didn't corrode why because in those waters all the copper rich phases in
the nickel silver corroded and the silver was protected and so the actual
objects when they're brought up are all fluffy and you've got to be careful that
you don't lose the fluff because it's all the silver plating wow and so you get
layers and layers and layers of different corrosion products and every
single one is telling you another story and you get funny objects like they had
modern clocks electric clocks and people say how do you conserve an aluminium
alloy clock from the Titanic and the answer is you don't because it's all
just a powder a mass of corrosion products but even in the aluminium decay
it's decayed in a Titanic fashion and so when you get the particular corrosion
products found on a wreck you say haha this can have only corroded at a depth
of greater than a couple of kilometres so it's it's a bit like building up your
detective you know list of when you've got this and this corrosion product you
say I know where you've been you can't treat me yes you were there because your
corrosion products tell you and one of the things is that under these
environments you see in the bottom part of the image I think you can see it
there a fork from the Titanic and my colleague said these forks are creating
they're fooling apart and I said it's because of all the copper chloride the
make corrosion products you can see above there that's that's what's causing
the problem and he said fix it or you get nothing to eat for a week and I like
food and I like French food and I said that you tried my method with the
pseudo nitrile and he said we did not use that stuff and I said look the only
solution is use my stuff or it'll fall apart so we treated these forks over
night and the next morning they were stable and it's because you use an
organic solvent that is 10 million times more soluble for taking out the
time bomb element of the copper one chlorides and within 24 hours these
rapidly corroding objects were stable so I reckon that was worth a meal
absolutely and I guess this is the last image and it's of one of the cherubs
from the staircase that was being electrolyzed so corrosion is when
electrons come off a thing and interact with the environment electrolysis it
isn't hair removal it's it's when you pour electrons back into the object and
the corrosion products go oops and nearly got rid of Emily's object and and so
with the corrosion gone the objects relax and they get a new life wow well
that's fascinating how many objects have been recovered so many hundreds of
objects and we've been able to stabilize them all and through different
chemical and sometimes physical methods and if you've seen the Titanic
exhibition the massive bit called the big piece that was actually part of the
side of the hull and I think that's one of the most evocative elements in that
traveling exhibition because you can actually go up and if you're lucky touch
it and it's pretty pretty compelling well on that the Titanic is decomposing
quite rapidly yes how long has it got in this current state well as a geo
article you video said probably between 50 and 80 years but one of the things
that people go and say oh it's suddenly collapsed no it's all planned decay you
iron as it corrodes the metal gets starts that thick figuratively they get
thinner and thinner and thinner and thinner until the point where it says I
can't stand this anymore the weight on top of him is too much and it just goes
and so all of a sudden a whole deck can collapse and it's a bit like as a kid
when you build up a big castle of cards one month when one deck goes boom boom
boom boom and so it can appear to be undergoing rapid collapse and people say
it's rapidly corroding but remember we've only been watching it for the last 15
or so years and all that corrosion has been steadily eating away and it's only
when corrosion eats in to leave you with very little to support a structure that
it suddenly appears to be collapsing okay well on that then should we be doing
more should we be trying to conserve more artifacts or trying to conserve the
ship as it is today well it's a bit difficult to work down there you need to
be inside obviously as submersible but the the real reason why expeditions
should still be going there is you can learn an awful lot about the complex
biology because you've got people think it's just a wreck oh no no no no no it is
a wreck that is dynamically interacting with the marine environment and there's
a huge amount that we can learn about the nature of the interaction with the
bacteria with the marine life and what impact that's having and what impact the
Titanic is having on the bacteria that live in the sediment that live in the
ocean at that depth and the more you can understand the better we'll be able to
manage the world not just of shipwrecks but of this incredible thing that keeps
us alive which is the world's oceans well that is fascinating I think what we
might do now is might just ask Emily to come back up if that's okay we'll start
just a bit of a general discussion sure but in the meantime in what I'd be
quite interested in just building on with this is you do talk about the marine
environment down there and the fact that most people think it's quite dead but in
fact it's quite alive with bacteria oh you bet people think that come on come
on up because this is entirely relevant for all maritime archaeologists and I
think Emily will agree that you've got a real biodynamic that's the word we use
biodynamic interaction of particularly iron wrecks with the marine
environment for example on the shallow Japanese World War two shipwrecks in
Chukla Goon where a ship might be over at say 30 degrees you've got a sunny side
and a dark side and on the sunny side the corals grow because they like the
light and they branch out and as they branch it causes the localized water to
increase the flux of nutrients to them and that's why nature branches our
corals because it's minuses I can't get up and move but I can have a complex
structure and it causes localized turbulence and that brings the nutrients
and so the colon says I'm happy but meanwhile that flux causes increased
oxygen to come into the metal and so it corrodes so we can pick up the
difference in corrosion rate between the light side and the dark side of a wreck
and while I can do those measurements in nice 25 30 meters of water can't do that
easily on the Titanic but I want to take my lab down there and do measurements
with little ROVs holding my electrodes for me because if we could understand
what is actually happening with the bacteria living above the surface and
just in the sediment the huge power that we could tap into in understanding
what what is happening for example when you get problems like oil wells going
pop and and oil being deposited on the seabed because bacteria opportunistic
if something comes along they go oh try this and and so when the Titanic comes
whack and and dumps itself on the seafloor all those bacteria that was
starved of iron for their mitochondria all of a sudden endless supply of iron
and they just eat well well they use it as an energy source and so because the
the iron is being consumed it pushes the equilibrium the other way so you could
say that the bacteria are eating the Titanic or you could say that the
Titanic is feeding the bacteria I mean it's carts and horses it's a matter of
perspective
