How to protect bare metal fastners

[Troy P.]

Quite a few fastners on our cars came without a plating or black oxide finish. Seems that bare metal was quite common.

When restoring these fastners what process do you use and how do you protect them from rusting? Looking for some good ideas from those with experience.

[Michael G.]

Re: How to protect bare metal fastners

Depends on what you are going to do with the car. If its a trailer queen, or your drive it rarely and only in dry weather, a thorough cleaning of all rust, then just an oil dip before assembly will last a long, long time. If your going to drive it in the rain or you live in a very humid area, you can try a satin or flat clear-coat to prevent rust for a while. For what its worth, a flat clear-coat looks very much like plain steel. I wouldn't put paint on the threads, though, as that'll bugger up the assembly clamp-load.

[Troy P.]

Re: How to protect bare metal fastners

Have you ever heard of heating the part and dipping it in oil? Theory is it will suck oil into the pores.

[Kurt G.]

Re: How to protect bare metal fastners

Heating the part then dipping it in oil will work. One thing I do is use anti-seize compound, the silver stuff. Coat the part in a light film of the compound, let it set for about a half hour then wipe it clean. I don't know how it works on a daily driver, but on my occassional sunny day avoiding water puddles car it works pretty well. Got the trick from a friend down in Dallas.

[Ronald L.]

Re: How to protect bare metal fastners

The heat and oil dip could change the strength properties, maybe not the right thing to do if the bolts are grade 5 or 8 to begin with, and the process its self is basically an oil quench that will result with a part darkish brown, close to the black oxide which as much as I write it, no one gets the idea it does not provide corrosion protection. Black oxide is rust, the colors of which range from black to umber to orange and red, depending upon how its combined with oxygen.

[Rich G.]

Re: How to protect bare metal fastners

Corrosion X is a liquid product that works well, but may have to be re-applied once in a while. It's electric friendly so it can be sprayed or brushed without worry about wires and switches and works great on battery terminals.

Rich

[Troy P.]

Re: How to protect bare metal fastners

Worth a try. Any other ideas out there?

[Troy P.]

Re: How to protect bare metal fastners

So you are saying black oxide is not a corrosion portection. Then why did they use it?

[Chris S.]

Re: How to protect bare metal fastners

Sharkskin and RPM
there are others out there

[Steven B.]

Re: How to protect bare metal fastners

Troy, Gibbs Brand is excellent for protecting non-ferrous and ferrous metals. I have used it for years and found nothing better. Steve

[Glen C.]

Re: How to protect bare metal fastners

I've been using Gibbs for a couple years now. Search Gibbs on this site for more information.

[Michael G.]

Re: How to protect bare metal fastners

Black oxide was purely decorative, it provides no corrosion protection.

Many here think that the finish on GM's black (actually dark grey) fasteners of the sixties was black oxide. The vast majority were not black oxide, usually they were zinc phosphate with an oil dip. The phosphate was there to absorb the oil, the oil was the corrosion preventative. Oil-coated steel fasteners, without phosphate to hold the oil, will rust quickly when exposed to water, no matter what magic oil you use.

[Gene M.]

Re: How to protect bare metal fastners

For the trailer queens rub the bare metal down with STP oil treatment it lasts for years. But be advised it makes handling the bolt to start them by hand a slippery task!

[John H.]

Re: How to protect bare metal fastners

So you are saying black oxide is not a corrosion portection. Then why did they use it?

Troy -

They didn't - for all practical purposes, no black oxide-finished fasteners were used on Corvettes. Most fasteners that folks think are black oxide are actually phosphate and oil.

[Donald H.]

Re: How to protect bare metal fastners

Troy -

They didn't - for all practical purposes, no black oxide-finished fasteners were used on Corvettes. Most fasteners that folks think are black oxide are actually phosphate and oil.

John, is the phosphate you mention the zinc or manganese phosphate treatment or Parkerizing? I just ordered some manganese phosphate to try to Parkerizing some bolts.