I am a stickler for details, not show car level but if I’m doing a project I plan ahead. I powder coated some valve covers and noticed the hardware was oxidized and crusty. I am using caswell black oxide and sealer. I also noticed how crazy expensive new hardware is. 1. Clean. I soaked in vinegar for a couple days. Then to a wire wheel on the bench grinder. The better the prep the better the finish. Like any other job. 2. clean again. A dip in a degreaser or other cleaner will do. Dry completely. Compressed air or heat gun will do. 3. Sit in the caswell black oxide in a 1:9 ration with oxide to distilled water. 4. The bolts will turn black before your eyes. Move around and wiggle to release air bubbles. No longer than 5 minutes in the solution. 5. rinse in clean water 6. dip in caswell sealer and let air dry. gloves should be worn at all times. If there are spots that did not take the black coating, it means it was still dirty. Enjoy!
they came out pretty good, but it is labor intensive, but all labor, my finger are killing me stripping the grommets then holding each one for the wire brush. I have seen better results with sand blasting the bolt heads and mixed reviews on media tumbilng the hardware, keep in mind these are some of the most difficult pieces of hardware to do because of how they are built, standard bolts will be much easier
after working at Fastenal for 12 years and seeing what the margin is on hardware, I cringe whenever I have to go somewhere to buy nuts and bolts. It's beyond highway robbery.
Several years ago I bought two large racks of nuts and bolts, $1500 worth. I have metric and USS course thread. I skipped the SAE fine thread rack for another $750. But I have hardware from 1/4" to 3/4" and metric 6mm to 20mm. Never mind the ridiculous cost of nuts and bolts at the hardware store, just the time savings is worth it for me.
It's absolutely worth it. Before I left Fastenal I got 2 72 hole bins with a stand for employee discount. I also got 4 boxes that each hold 4 pull out drawers for small stuff (electrical connectors, tiny hardware, cotter pins, etc) for free. One of my customers knocked the tower over and wanted them all replaced, so I got the original stuff. It's worked out great. Luckily, I still know people at the fastenal branch I work at, and the job I have (local government) has an account there, so I get hardware super cheap, but not employee discount cheap.
I got to figure out a jig to hold these, the few i did killed my fingers. so coming up with something to screw them into to make holding them to the wire wheel easier. since i have a few sets of valve cover bolts i picked up from the junkyard
I ended making a jig using a nylon spacer and tapped it using my m6x1.0 tap. Threaded the bolt in with a jam nut. Allowed me to clamp down with vice grips and not damage the threads. And much easier on the hands/fingers. I did a few more tonight. Just wanted to show what happens when the surface is not clean enough for the black dip. I’m not sure what was on this particular bolt but it turned rust brown. Back to the vinegar dip and wire wheel
I used to use muriatic acid and ospho. Now it’s heavy gloves and a wire wheel bench grinder. if I had to clean hundreds of these I would invest in a media blaster or ultra sonic bath but I only do few of them every year so no big deal.
Heh, story of my life, for 25+ years. I wire wheel as little as possible, just get the rust off, then hit with phosphoric acid, then put them in cardboard and coat the heads with spray on zinc. Good enough. Just throwing new bolts at everything is bad for the environment! Reduce, reuse...
do you think a soak in muriatic acid will prep the surface enough for the black oxide dip? Is it the same muriatic acid used for pools? I have gallons of that
I used to use it to get surface rust off. Came in a red gallon from the chemical store. Try it on a surplus rusted bolt first.
