The subject of this edition is the use of Eastwood's Blackening System to restore
the look and protection level to parts and fasteners that originally had a black
oxide finish. The bolts used in this edition are the ones that bolt on the structural
cross member under the transmission which is used on convertible Falcons. As can
be seen in the photos, these bolts with integrated conical washers are quite unique.
I had tried to replace them, but was unable to find exact, or even suitable replacements
(other than standard zinc plated bolts with large zinc coated washers and lock washers,
which I thought would look pretty cheesy and probably wouldn't do the job as well
as the original fasteners). Other than being very greasy with light surface rust,
these original bolts were in generally very good physical condition, with only some
minor physical damage to some of the heads and very light pitting on the conical
washers. The threads were in excellent shape.
As will be seen below, these bolts were dipped in the blackening solution, but the
solution can also be brushed on larger items if necessary. All parts to be blackened
must be steel or iron. The system will not blacken stainless steel, aluminum, or
any plated or otherwise coated steel or iron part. Only ferrous metals will blacken
with this system and they must be completely stripped of rust, paint, old blackening
oxide, grease, oils, etc., until only bare metal is exposed. As mentioned in part
one of this edition, the blackening process actually oxidizes the surface metal and
seals it with a coat of its own relatively stable oxide which is quite hard and fairly
resilient. This system also uses a sealer solution that the blackened part is dipped
into or coated with which ultimately determines the corrosion resistance and good
looks of the part over time. I discussed this procedure with a metallurgical engineer
friend and need to pass along his thoughts. First off, black oxidization is certainly
more stable than plain rust oxidization. However, when viewed microscopically, the
black looks like a bunch of tiny black balls stacked on top of each other. Without
some sort of sealer, water would seep between the “balls” and get to the bare metal
and cause rust oxidization. Thus, this system uses both a black oxidizer, and a sealer
to keep the metal corrosion resistant.
I first degreased these bolts using solvent (paint thinner also works well) and then
used a media blasting cabinet to strip these bolts to bare metal. I then degreased
them one last time with acetone before blackening them.
Before and after views. The bolts were very greasy and dirty with gritty road grime.
The left photo shows them after being degreased with solvent and dried with compressed
air. The right photo is after the process is complete.
This is one of the bolts after media blasting & degreasing, ready for blackening.
Items for blackening must be blackened immediately after stripping or the "flash
rusting" that occurs from humidity in the air will interfere with the blackening
process and the finish will not look as good, or perform as well as designed. Don't
strip parts today and plan on blackening them tomorrow. Wait until you are ready
to blacken them before you strip them. The blackening process is very quick (about
five minutes) so it can easily be done right after stripping & cleaning.
As mentioned above Eastwood's system consists of two solutions. The blue solution
on the right is the blackening solution. The orange solution on the left is the sealant.
The blue solution comes as a concentrate in a separate bottle and is poured into
the container shown above. It is then diluted with distilled water till it is two
inches from the top of the container. As seen in the photo I marked a spot two inches
below the top for ease in setting the system up. The sealant comes ready to use and
needs no dilution.
For several days before actually using the system I considered the best way to dip
parts in the blackening solution. Dipping them while holding on with some sort of
tweezers or pliers wouldn't work since the place where the part was gripped wouldn't
get any solution on it and therefore wouldn't blacken. I thought of suspending the
parts with a wire but also worried about the wire blocking complete solution coverage.
I looked at small kitchen-type strainers and even small fish nets from an aquarium
store. I finally settled, believe it or not, on an old plastic Kraft grated Parmesan
cheese container as seen above. It fit perfectly onto the opening of the bottle provided
with the blackening system. After washing it in the dishwasher, I drilled holes all
over in the sides and bottom to make a sort of "strainer basket".
This shows the stripped and cleaned bolts in the new "strainer basket" and better
shows the holes drilled in the sides and bottom.
The left photo shows the bolts about to go into the solution. The right photo shows
the bolts completely blackened after just 30 seconds in the solution (Eastwood says
20 to 60 seconds depending on the part). To make sure each bolt got full coverage,
I jostled the bolts around inside the container during blackening.
After blackening, the parts are rinsed in distilled water for 10 to 20 seconds (again
jostling them around while in the water).
The parts are then dipped in the sealer for one to two minutes (again jostling them
around occasionally while in the sealer).
When the parts come out of the sealer they are left to dry with no rinsing. Eastwood
says it can take anywhere from one hour to overnight to dry depending on the part,
the temperature, and the humidity. These bolts took about five hours to fully dry
at about 70 degrees Fahrenheit (20 degrees Celsius) and about 60% humidity with a
light breeze blowing on them (I put them by an open window in the shop, both for
the help of the breeze in drying them and to allow the slight fumes from the sealer
to escape outside during drying).
These are the finished product. They look and feel like brand-new black oxide bolts
(the slight variance of color on the finished bolts in these photos is due to the
high level of JPEG compression algorithms in the digital camera I used -- the bolts
really have a uniform satin black appearance just as new ones do). Of course, any
damage to heads or other parts of bolts, nuts and screws that was not taken care
of prior to blackening will still be there, and the underside of several of these
conical washers have minor but visible pitting from the previous rust. But they should
now function as well as they did when they were new, which means they should last
at least another 45+ years. Again, this is a lot of work when compared to just buying
new bolts. This whole process, including degreasing, media blasting, and blackening
took about two hours -- for just six bolts. There are hundreds of nuts, bolts and
screws for this car and if I took this amount of time to restore all of them this
project would drag on a lot longer than I want it to, which is why I decided to replace
all the fasteners that I could. However, if you would need to replace some of your
original black oxide fasteners or other black oxide parts with something less desirable
than the stock item, and they are in generally good condition, then this blackening
system may be just the ticket. If you process a lot of fasteners and/or parts it
will even save you money over buying new replacements. I've spent over $150 on new
replacement fasteners for this car. However, right now I am anxious to get this project
finished, so if I can save time buying new fasteners I will most likely do so. But
I am finding that there are many specific fasteners (such as these shown here) and
other small parts that originally had a black oxide coating that no one is presently
reproducing so this system gives me a way to still get the job done, and done right.
Discussion & Procedure
Bolts & Fasteners
This is the end of the Restoring Nuts, Bolts, & Fasteners Edition
Feel free to save this page to your computer for your personal use and future reference--no
other use is authorized without prior written permission from me. All illustrations
from the 1964 or 1965 Falcon Shop Manuals used pursuant to permission granted by
Ford Motor Company. Disclaimer: This site is not intended to instruct or teach anyone
in proper or safe methods of working on or maintaining any type of vehicle or use
of any tool and the author takes no responsibility for the use of the information