Prepping and Painting Fasteners

9

95YJLS

My 95 Jeep Wrangler is in the middle of a frame-off. The exterior door & windshield hinges had countersunk Torx fasteners, and several of them were seized due to paint getting in the threads, or in one case cross-threaded. I had to drill them out and find a replacement fastener.

What I ended up with is Allen-head countersunk machine screws, finished in black oxide.

My question is, what do I need to do to these to prep for paint? I believe black-oxide finish is soaked in oil, which works its way into the porous coating. Brake cleaner? Soak in denatured alcohol? Dawn & water? If I can get the oil out of it, the black oxide should drink up epoxy primer for a very strong bond.

For painting, I'm thinking:
1) Stab them in a piece of cardboard
2) Epoxy primer - two coats
3) Base - two coats
4) Clear - two coats

Is that too much paint?

Thanks
 
Someone on another car-specific forum mentioned coating bolts using Cerakote which is typically a gun coating. I'm not familiar with the product, but it seemed like an interesting option. My concern with painting bolts using traditional paints and epoxies would give too much build up on the bolt. This could lead to damage of the coating from the tool during installation or removal. I'm not sure if Cerakote would be thinner or more forgiving.
 
I recently tried epoxy only on a handful of fasteners, if there's a trick I do not know it. As mentioned as soon as I started putting them in place the socket started taking the epoxy off. It still looked better than nothing at all, but that doesn't sound like what you're looking for.
 
I am doing a frame off restoration of a ’55 Studebaker. It is not a frame off, every bolt and nut replaced but is a frame off and every nut and bolt at least painted. I read on a forum that someone had pretty good success with a Harbor Freight tumbler. I bought the cheapest one along with some pyramid shaped medium to use in it.

It has served me well. I put a cup full of nuts, bolts and about anything else that will fit in it and turn it on and let it do its thing for 24 hours or so. Most of the surface rust is taken off. I then replace that medium with crushed walnut shells that the pet stores sell for lizard habitat. Many re-loaders use it to polish their brass. I put the small parts in that and let them run another 24 hours. I then clean them, epoxy prime them and paint them.

Charlie D.
 
Most factory nuts, bolts and washers that were not shiny from silver zinc plating were treated with zinc phosphate. Black oxide isn't use because it is only a thin surface coating whereas zinc phosphate reacts with and deposits a layer on the surface. With the zinc phosphate coating you can apply oil like the auto manufactures or paint them. It's very easy to do at home (zinc phosphate or bright zinc plating).

Mike
 
Most all of the cars I do get the fasteners re-cadium plated. The black fasteners go through a black chromate to change the silver cad to the color black. This process lasts much longer than the black oxide dips.

When I rarely do have to paint some fasteneres like on 40's GM door hinge screws. I blast just the head with 80 grit aluminum oxide. Then I spray the epoxy. The epoxy needs that rough bite or it can flake off when a wrench is applied. I just poke them in a carboard box and spray them.

That is a good setup Charlie and you don't want to replace every nut and bolt on that Studebaker. The new hardware doesn't look the same or have the right markings. Leave the new nuts and bolts to the rod guys.
 
Brad J.;n83137 said:
Most all of the cars I do get the fasteners re-cadium plated. The black fasteners go through a black chromate to change the silver cad to the color black. This process lasts much longer than the black oxide dips.

When I rarely do have to paint some fasteneres like on 40's GM door hinge screws. I blast just the head with 80 grit aluminum oxide. Then I spray the epoxy. The epoxy needs that rough bite or it can flake off when a wrench is applied. I just poke them in a carboard box and spray them.

That is a good setup Charlie and you don't want to replace every nut and bolt on that Studebaker. The new hardware doesn't look the same or have the right markings. Leave the new nuts and bolts to the rod guys.

Who do you use for the plating? Local place or?

Also, yeah I only cleaned the hardware I did not blast it, I bet that's why I had issues.
 
Another thing about the epoxy, it's best to let it cure a few days if you can before using.
I have even baked them in an oven at 200 deg.
 
I have the Caswell Cadium plate system and it works pretty good. For years it was all I used but we have a Plater in Michigan that does them cheaper than I can. They do work for and ship all over but I drive my parts there and home. 1.5 hour drive but most of the hardware I'm playing with is irreplacable and I don't want to lose it.

He doesn't do the prep though. That means I have to glass bead everything or tumbler. Tumbler doesn't work good for me and I end up at the blast cabinet. Usually an entire cars worth of fasteners is 8 hours at the blast cabinet and $200-400 at the plater depending on how much stuff. I'm doing all the carb linkages, hood hinges, everything that is plated. I've been looking at used commercial tumblers but haven't done it yet.

PlymouthLandinc. is the plater. Plymouth Plating is the company and the owner spun the Plymouthlandinc. to seperate the resto work from the production.
 
I just went with the 316 stainless steel allens when we did the 90. Dont use 18-8, they will rust. They have some black oxide stainless at McMaster Carr as well, but those also rusted. It just made sense, especially with Allens, there is no way that paint is gonna be in there after you assemble. You can use a baggie over the hex head to protect the hex bolts, but allens are tough on the fastener.
 
I'm in the resto crowd so OEM finish is essential. I do all my own plating at home because I control the quality and there always seems to be a nut or bolt that was missed when doing a batch. For all parts I'll glass bead using a Harbor Freight media cabinet, or in the case of bright zinc, strip in muriatic acid, prior to plating (phosphate or bright zinc). For zinc phosphate I have a pint of Brownells Zinc Phosphate Parkerizing (#082-091-016) and that is more than enough to do a couple of cars. For bright zinc plating I use home products (ex: white vinegar, corn syrup, etc) and zinc anodes you can buy on eBay or Home Depot. I'll also give the bright zinc parts a 10 second clear zinc dichromate bath to increase the rust protection. I have a write-up for bright zinc that works excellent but this site will not let me upload a Word document as an attachment so if you are interested in it just send me your email and I'll send it out. I attached a picture from the Camaro restoration scrap book showing some hardware plated at home. bolts_sample.JPG

hardware.JPG
 
Good info! After the epoxy not working that well (definitely my fault) I started picking up ARP stainless hardware and for sure blew by 200.00. So that plating company sounds like a deal honestly.

MikeS, I'll PM you my email, I'd like to see your write-up!
 
Head markings and correct nut shapes are essential to a factory restoration so replating your hardware is the way to go especially when you do it yourself.
One thing I left out was just before I put the parts in the zinc solution, I will boil them to float off any remaining oils that may get past the denatured alcohol bath. Also, boiling the parts to be zinc phosphated will also raise the temperature and make them plate sooner when putting them from the boiling water into the pot (stainless steel you can get at a dollar store) containing the phosphate solution, which should be approximately 160-190 degrees. Just don't let the solution boil, so use a meat type of thermometer that goespast 220 degrees (another dollar store item).
I sent you the document.

Mike
 
Raymond_B;n83100 said:
I recently tried epoxy only on a handful of fasteners, if there's a trick I do not know it. As mentioned as soon as I started putting them in place the socket started taking the epoxy off. It still looked better than nothing at all, but that doesn't sound like what you're looking for.

If you'll put a thin piece of plastic over the bolt head then put the socket over it, the paint won't crack as bad. I'd be interested to know how the folks that paint in pieces and then assemble handle this, especially if the bolt needs to be body color.
 
A few notes:
-These fasteners are flathead cap screws which were used to install the door and windshield hinges.
-They sit flush in a countersunk hole in an exterior hinge.
-The factory assembled the doors and windshield before painting. I would like to match that look.
-The OEM fasteners were cheese-grade steel, T40 Torx. Several of them had to be drilled out because they were too seized, and the Torx splines twisted right out. They are being replaced with a superior fastener of hardened alloy steel. With extreme prejudice.

It sounds like nobody has tried painting directly over black oxide. I may have to do a few experiments and see if it will work. If the epoxy primer won't take to the black oxide, I'll throw them in with the other bits and pieces that are going out for media blasting.
 
If providing a base for epoxy to grab into is your goal then I would just use a media blasted part and skip the oxide treatment. If the paint chips off the part that has an oxide layer under it, it still may rust because black oxide by itself (with no oils) provides very little corrosion protection. If it were mine I would use sand as a blasting media to get a course surface and keep the layers of epoxy and paints thin so as to reduce the risk of chipping when torquing.

Mike
 
I have an older Porsche that has painted door hinge bolts. During restoration the PO did not paint the bolts so I need to go back and paint them. I figure I will have to paint them off the car and them hope the don't chip during installation. From what I read above, it sounds like I should media blast for tooth, prime and paint. If I media blast, won't that break the surface protection provided by plating and open up possibility of rust? Obviously, if I get a small chip, I would simply touch it up, but hoping the color coat will hold up. The other option would be to mask off the hinge and paint it as a unit, but more work for sure.
 
merbesfield;n83234 said:
I have an older Porsche that has painted door hinge bolts. During restoration the PO did not paint the bolts so I need to go back and paint them. I figure I will have to paint them off the car and them hope the don't chip during installation. From what I read above, it sounds like I should media blast for tooth, prime and paint. If I media blast, won't that break the surface protection provided by plating and open up possibility of rust? Obviously, if I get a small chip, I would simply touch it up, but hoping the color coat will hold up. The other option would be to mask off the hinge and paint it as a unit, but more work for sure.

The factory bolt base finish is more likely zinc phosphate but without the preservation oils.Though much better than a black oxide finish, even an unprotected zinc phosphate coating is subject to corrosion without some type of preservation on it (oil, paint, etc....). If it were my car and I had good access to the bolt/hinge area, I would mount the hinge with the bolts and mask it off then use a touchup gun or an airbrush to spray the bolts. I'd start outlining the bolt edge with an 1/8" pinstripe tape to get a tape edge established around the bolts then add another layer using a 1/4" masking tape overlapping the pinstripe to build it out more then mask with paper or plastic and spray.
 
MikeS;n83219 said:
If providing a base for epoxy to grab into is your goal then I would just use a media blasted part and skip the oxide treatment. If the paint chips off the part that has an oxide layer under it, it still may rust because black oxide by itself (with no oils) provides very little corrosion protection. If it were mine I would use sand as a blasting media to get a course surface and keep the layers of epoxy and paints thin so as to reduce the risk of chipping when torquing.

Mike

On these particular bolts, they came finished in black oxide with light machine oil from the manufacturer. I was hoping I could skip the media blasting step and just give them a good wash/soak in some solvent, shake them up for a rinse in Wax & Grease remover, and paint right over the oxide. The black oxide on these has decent roughness to it, about what you would see from fine grit media blasting. Next time I mix up a batch of epoxy primer, I may just shoot a few prepped this way and abuse them a bit to see if there are chipping issues. If that doesn't pan out I'll media blast.

So, should I do all three steps, prime/BC/CC before assembly, and touch up after assembly? Or maybe it would be better to prime > assemble > BC > CC (with the understanding that I've glued all my hinges to the body, and will have a hard time if I ever need to take it apart again).
 
old thread but i tried with some success is to get a cup of motor oil then take your hardware and heat it up with a torch or put them on a cooking sheet and get them real hot so the metals pores open up some. then go ahead and cool them off in the motor oil. the oil gets into the open pores of the metal and will turn them black too
 
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