Carbon8

iTrader: (4)

Intro (Cadmium vs Zinc vs Black Oxide)

If your like me and are meticulous about your car, only to find that 10+ years on the road has not been so kind to your nuts and bolts then I have found a viable option to easily restore them.

Mazda originally built the Rx8 using all cadmium coated hardware (the gold coating) they have then since over the last decade switched over to zinc coated hardware. If you ever noticed your replacement bolts are silver and not gold.

Both are great coatings, the only draw back on cadmium is that it is designed to fail. Cadmium coating is designed to take the corrosion to protect the steel bolt by first corroding itself. This is a process and some of your current hardware may already show signs of this. Only drawback is once the cadmium corrodes it leaves the steel fastener helpless against the elements. Hence the switch to zinc which is designed to prohibit corrosion altogether.

Now both cadmium and zinc platting is done using an electrical charge etc.... so it is not a viable option to set up at home just to do a couple hundred bolts. The investment is to large, it would be cheaper just to by all new OE replacements.

Because of that I stumbled upon a black oxide plating process which can be done cold and requires very little investment and experience. Now black oxide is a chemically induced controlled corrosion plating process. The platting solution oxidizes the steel leaving it a black to a dark brown/grey appearance state. Now because you are corroding the metal during the plating process black oxide coating is not ideal for automotive fasteners that will see much elemental abuse, unless it is sealed in which case it will hold a substantial rust prohibition.

Now even with the sealant, I do not strongly urge this plating process on anyone that daily drives their car in a climate that requires road salt. Being that my car never sees those conditions I decided to give this process a shot and see how it works.

What You Will Need

CasWell Supplies

• Wire wheel ( I used a bench grinder with a brass wheel)
• Gloves
• Steel Wool (000 Grade)
• 6 Buckets 2qt or bigger
• 5 Baskets (Large enough to hold hardware but small enough to fit inside the buckets)
• Towels
• De-greaser (Liquid Degreaser Concentrate - Caswell Inc)
• Rust Remover (Evapo-Rust Rust Remover - Restoration Aids - Caswell Inc)

Black Oxide Platting Kit ( I got mine from CasWell Plating, I ordered the 2.5 gallon kit and have enough left over to make 2-3 more platting sessions)
Black Oxide Kits - Metal Finishing Solutions - Caswell Inc

The kit only comes with the penetrating sealer (Basically WD40) you will want the CasWell Sealer as well
Caswell Sealer - 1 Quart - Black Oxide Kits - Metal Finishing Solutions - Caswell Inc

All in all it ran me $400, which seems like a lot but I have enough supplies to do every nut and bolt on 4-5 cars if I need to. Also the solutions have a shelf life of 10 years as long as they are covered and in a climate controlled environment.

Process

Step 1-Cleaning

Start with your rusted/dirty hardware and using the wirewheel clean all debree off the parts. Now is using a bench grinder wear gloves and eye wear and for the love of god use vice grips!!! I don't know how many times I have seen hardware become a projectile because someone used their fingers.

Before Cleaning

After Cleaning

Step 2-Prep

Now that the hardware is free of physical contaminates it is time to prep the pieces for coating. In this stage you will need to place the parts in the basket and place the basket in the rust removing solvent. You can leave the part in as long as needed, even over night if it is really bad still.

Rust Remover

Take the basket out of the solvent and rinse it using tap water, you will then immediately place the rinsed parts into the degreaser for 5-10 minutes.

De-Greaser

Again rinse the hardware after taking it out of the solvent and notice if the water is beading off of the pieces and flowing smoothly to determine that the parts are contaminant free.

Step 3-Black Oxide Platting

Now that the parts are properly cleaned and prepped they are ready to be dipped into the oxide concentrate. Leave the parts in the oxide for 2 minutes, then remove and rinse. Once rinsed lay the parts out on a towel and place the basket back into the oxide solution. Now take your steel wool and scuff and pieces that do not have even coverage. after they are all scuffed place them back into the oxide solution for another 3 minutes, rinse and lay on a towel when complete.

Black Oxide Solution

Black Oxide Rinse

****Do not leave parts in solution for more than 5 minutes****

Step 4-Sealing

Now that the parts are coated and have dried they can be sealed. This process is the same as the rest, place the parts in a basket and into the CasWell Sealer first. This process is a dipping only 2-3 dips to ensure an even coat the parts do not need to sit in the sealer. Lay the parts out on a towel again to dry (10 Minutes). Once they are dry you can then repeat this process for the penetrating sealer.

The penetrating sealer is an oil, and as such will take days to fully dry.

Black Oxide Sealer

Notes

This process can be adapted using brushes, sponges and towel to coat studs that are attached to a coated piece. For instance I did the studs on my coil bracket. The solutions will not degreade of damage existing coatings. So it can be applied easily with a brush and then wipped away without concern at the end.

Coil Bracket Before

Coil Bracket After

logalinipoo

Looks good carbon