Hello in this video we going to discuss
the basics procedures for preserving
historic iron fencing. Two things to
keep in mind are to first do no harm to
the artifact itself and secondly always
exercise personal safety.
The first step before beginning any restoration
project is documentation. It is important to
document the fence as you found
it before any work begins. This may be done
by filling out a survey form or just
writing a narrative description of the
fence’s condition. It is always a good
idea to take lots of before, during and
after pictures of the project Keep in
mind to take pictures of both the details
and the overall area.
One detail to keep in mind when documenting
your fence is to look carefully on the
ironwork for any remnants of the original or
older paint. On a heavily weathered
fence these may be found underneath the
rails or where parts connect.
Generally, we think of fences
as painted black but historically
a fence could have been painted a variety
of colors such as green, white, or even
have metallic plating. If any remnants
of the older paint are left this should
be photographed and included in the
documentation. This may also help you
decide what color to paint the fence.
While we are writing our documentation let
us discuss ways to distinguish between
cast and wrought iron- Cast iron is made by
heating iron to a fluid state and then pouring
it into a mold. It is fabricated in sections
that are then bolted together. Cast
iron is heavier but cheaper to make.
The molds allow for more intricate details.
However Wrought iron is iron
drawn and worked slowly
with continual heat and pressure.
Since it is shaped by forging,
this allows for simpler, more delicate pieces
and is lighter than cast iron.
The pieces are put together with rivets
or fused together. The fence that
we will be working on in this video
is a wrought iron fence that has
cast iron corner posts.
Now that we have documented the project,
the next step is to always cover up
any objects in the area where
the work will take place.
It is particularly important
to cover up any stone grave markers.
As well as any stone or masonry
curbing that may be under the iron work.
Rust, chemicals and the paint will all
cause damage to the stone.
Another important thing to check
on the fence is that the bottoms
of the iron panels are free from
the ground. Only the corner
posts and support brackets should be
in direct contact with the soil.
Any unnecessary ground contact will
cause the iron to corrode.
If the fence panels are in contact
with the ground they may need to be
raised for most likely the soil should
be dug out from underneath them.
Now that you have been paying particular
attention to the fence you may have noticed
loose, disconnected or broken connections.
It is important to fix these so that the
fence will be properly supported.
Tighten all loose bolts first;
use of a lubricant. If any bolts
are missing these will need to be
replaced at this time, you may want
to remove one of the original bolts
to match the size and style for the
replacement.
Iron bolts are the best
replacement but stainless steel may
also be used.
Occasionally, bolts are
broken off or rusted in the brackets.
These will need to be carefully drilled
out and the hole re-tapped to its
original size if possible.
It is important to center punch the hole
and use a drill bit smaller than
the original hole.
Ok, lets get started checking
to see if the fence panels and posts
are straight and level.
If they are not you may want to lift
or lower the corner posts.
This is only important if the
panels are so far out of alignment that
they are not fitting together correctly.
In some cases posts may be set in stone
or concrete. If the base of the post is
too heavy or large to dig around
then it should be left alone.
Otherwise the base of the post will need
to be exposed and lifted to the desired height.
Gravel or dirt can then be placed under
the base to stabilize it at the needed level.
The next order of your project is
to check if any of the wrought iron parts
are bent or damaged.
If there are any bent elements on your fence,
these can be easily straightened with little effort
and the right tools.
Now that we have addressed all of
our structural issues lets work toward
stabilizing the iron.
We want to remove only the loose
powdery oxidation and any rust scale
that is on the surface.
Keep in mind that we are going
to treat this fence with a rust
converter so some rust must remain.
To do this we are going to use a
stainless steel fine wire brush.
Heavy corded or twisted wire brushes
are too aggressive for historic iron work
and can easily remove too much material.
When selecting a wire brush you
want to choose a finer wire.
The fine wire lasts longer and is
more flexibility to reach tough
spots and corners
I do not recommend sandblasting
since some of the fences' detail
could be lost and the iron will get
over cleaned.
Once the surface has been wire brushed
you will need to remove all
the loose rust and dirt.
Washing the surface with a
solvent or a non-ionic detergent that
can be mixed with a solvent will
clean and prepare the surface for painting.
This wash will also remove any oil
left behind around the bolts.
After the surface is completely
dried of all moister,
we then treat it with a rust converter.
Keep in mind this is a rust converter;
not a rust inhibitor or rust dissolver
but a converter.
A converter works by chemically changing
the iron oxide into a more stable iron
tannate or iron phosphate.
Most commercially available rust converters
are phosphoric acid or tannic acid based;
some are even a combination of the two.
The only word of warning if using a
phosphoric acid based converter is that
moisture including high humidity
can not come in contact with the surface
until the treatment has completely cured.
If affected by moisture the surface
will turn a chalky white and
must be re-cleaned.
Keep in mind that when using any chemical
to follow the manufactures recommendations
for safety and personal protective equipment.
The rust converter must be brushed
or sprayed on all surfaces of the iron,
paying attention to coat any
under surfaces and crevices.
Use extreme caution if spraying
the converter because any contact with
stone will cause a irreversible black staining.
Once all iron surfaces have been treated
with the rust converter it must have
adequate time to cure before
you can move forward with the restoration.
Check the manufactures label for
the curing time of the converter
that you are using.
Once your surface has dried
and the converter has had time
to properly cure you can
begin priming the fence.
You want to choose an oil
based primer that is specifically
designed for use with metal.
Some primers have rust prevention
additives these are good but not
necessary since you have already
used a rust converter.
One to two coats may be needed
depending on the coverage.
You want a nice even coating that
is free of any gaps.
It is recommended that all primer
and paint be applied by brush to
prevent over spray and staining
in the cemetery.
Now that your primer has had time
to dry we can begin our top coat.
The color that you choose to paint
the fence is your own choice that
may be affected by the fences original
color or colors commonly used when the
fence was originally installed.
You may need to consult local ordinances
to see if there are any color
restrictions in your cemetery.
When choosing paint you want an
oil based paint designed
specifically for use with metal.
Two coats of paint are preferable to
get a good solid surface coating.
Now that you've watched this video,
hopefully you'll have all the basics
you need to preserve a historic
iron fence.
one thing to keep in mind:
if your fence is heavily damaged
or corroded is to consult a
professional conservator.
And always remember to exercise personal
safety and to do no harm to the object itself.
And good luck.