Black Oxide Coating

[Cudajason]

Hey guys,

after seeing Cody's video I am thinking of trying some black oxide coating on my transmission bolts.

How durable is a black oxide treatment, against rusting etc. ?  Will it hold up after the case is assembled and the bolts are hit with a wrench / ratchet.

Jason

[YellowThumper]

Curious on this myself.

[rebelyell]

It's not that great. Black ox is more of a vanity coating than it is hard corrosion resistance. Phosphate is what you'd want if you're looking for corrosion resistance.

[Burdar]

Black oxide is just black rust.  It's for looks only.  Parts will start to develop "red" rust if the black oxide is not sealed.  If you are buying it from Caswell, you can use their sealer but it stays tacky.(doesn't completely dry...which might not be an issue on trans bolts)  You can use RPM but a trans gets really hot.  The RPM coating will melt and re-harden every time the car is driven.(not sure how long that would last)  You can also spray them down with WD-40.  That will eventually dry too.  Then there is always a matte clear.

[Mrbill426]

POR-15 makes a product called Metal Prep (used to be Metal Ready) that sets up a phosphate coating.  Depending on the type metal and time of exposure to the solution it turns the surface to a medium gray to almost black.

It's not that great. Black ox is more of a vanity coating than it is hard corrosion resistance. Phosphate is what you'd want if you're looking for corrosion resistance.