jacksonwest

For the last couple of months I've been building up an old Mercier 100 frame after earning digging rights as a volunteer at San Francisco's bike kitchen. I chose it in part because the frame paint wasn't in great condition, making it presumably less attractive to potential thieves and less of a tragedy if I screwed it up during restoration.



In some places it's been worn to bare steel, in others just the primer, in yet others it's crazed (suggesting it once lived somewhere with cold winters and hot summers). But there was no flaking and what discolored metal there was peaking through the paint seemed more like a "browned" patina, and no loose rust came off onto my rags when I cleaned it up with water and degreaser.





After cleaning, I did give it a wax. The bottom bracket also showed little if any rust, so after flushing the tubes with water and degreaser and treating it with a mild phosphoric acid solution, I hit it with Frame Saver and then started the assembly.

Now, a few weeks later, having done a good deal of wrenching and a few dozen miles of riding, the exterior of the frame looks none the worse. But having accomplished all my mechanical goals, the only things left to do are to preserve and beautify. This is my first build from a bare frame, and I built it specifically to be a daily city bike. In theory we still have a rainy season, and in practice pretty much every road leads to a coastline, so I'd like to do everything I can to prevent corrosion and maybe keep this bike boom survivor rolling for another 40-plus years.



As far as I can tell, the original paint job wasn't exactly top-grade -- I'm guessing a baked enamel, with sprayed stencil artwork and a little brushwork on the lug lining. No clear top coat like on my Raleigh-Carlton. I could continue to just wash it after wet or dirty rides, wipe it down and spray with furniture polish for regular upkeep and treating it with paste wax during annual or semi-annual servicing.

But I also live on a block surrounded by auto-body shops with spray rooms, and thought I could maybe get one of them to include it in a batch to get an epoxy clear coat spray after I'd prepped it. My idea for prep is to first treat any existing surface rust by wrapping it in shop towels soaked in Evapo-Rust, then priming the bare metal with Testors model enamel (I'm currently testing a mix of Flat Black with a touch of Chrome to approximately match the dark silver of bare steel). Once I've got enough coats of primer that the chipped and scratched areas are flush with the painted surface, and it's had two days to cure, I'd give it a light sanding with 600 or 1000 grit sand paper and a light buff with polishing compound. Then I'd give it all a good wash with degreaser followed by a 3M "No Scratch" sponge and alcohol rubdown before turning it over to the body shop.

My questions are: Has anyone gotten a clear coat spray over existing paint? Could there be problems with the epoxy bonding to the ancient enamel? If I don't get all the rust, or get flash rust in the time it takes to apply primer, would the clear coat simply create the kind of anaerobic environment under which corrosion would fester? If I do get the clear coat, should I mask what's left of the decals or have those sealed under epoxy as well? (Naturally I'd mask the chromed parts of the rear stays and the headtube/bottom bracket.)

Of course I could simply get the clear coat and the old paint stripped later, but this is not exactly a vintage bike that's worth a full re-paint, at least not until I've had few years for it to prove its utility and for me to form even more of a sentimental bond with it. And the shinier it gets, the more likely a potential thief might actually mistake it for something truly valuable. I could certainly start the prep process and get it all the way to the polishing compound and final buff before deciding to just keep washing and waxing it as necessary.

Any experience or advice greatly appreciated!

Grand Bois

I would wax it and ride it, but if I had it clear coated it would be with a two part urethane.

Bad Lag

The rust will continue to corrode the steel beneath the paint (clear coat). Rust never sleeps.

jacksonwest

Thanks. I might have mistaken "epoxy" for "urethane," being more familiar with the two-part adhesives. The one body shop I chatted with someone at mentioned I could get some mixed up at City Paints, but not having a sprayer (or a shed), that wouldn't be much use to me. Assuming this isn't the kind of thing that you can brush on with decent results. They do sell rattle cans of 2K, and I do have a somewhat enclosed but well ventilated outdoor area, so if I was willing to accept some dust and bugs I could probably swing it. I will probably swing by City Paints just to clarify specifically what to ask for in any case.

As for the rust, is there no way to completely eliminate it? Are all steel frames and components rusting - if only in trace, microscopic amounts - before ever leaving the shop?

Grand Bois

It will slow down the rusting process because it deprives it of oxygen, but there is no stopping it. All of our steel bikes will be orange stains in the soil some day.

jacksonwest

Went down to City Paints, and the incredibly helpful Rodrigo answered a lot of questions. Will probably go ahead do some surface rust treatment, a little touch-up with my enamel "primer," buff it level then polish, wax and see how it looks. If it looks better, and not too sad compared to polished components, might hold on through the winter to see if I'm still riding it and if it holds up well enough to exposure.

This is partly just experimental, though, to see how much I can learn and how far I can take this frame makeover. So if some money comes my way I may just attempt a DIY rattle can job with Rodrigo's recommended 2K because why not? That said, I'm so happy with how solid I've gotten the ride, my eagerness to disassemble it again is waning. And I'd need a 23.35mm puller to get the old Stronglight cranks off in any case.

Lascauxcaveman 

Does this mean you haven't serviced the bottom bracket yet? You should buy, borrow or rent the correct puller and get that done, regardless of what else you do to protect the frame.

It does have a nicely grungy patina to it; I like it a lot.

Wulf

If you use a 2 part paint; epoxy or urethane, you MUST use a quality respirator mask. Adjust it tight and ir you can smell the paint, its not on correctly.

jacksonwest

Yeah, one of the disposable (72 hour use) respirators is on the list. I figured out a place I could hang the bike and some tarps outdoors behind the trash cans underneath my building that I could sneak in the work without giving my neighbors or landlord anything to be concerned about.

I serviced the BB first thing, since when I found it there was a Stronglight spindle with pitted races and for one of the 73mm BB Raleighs that someone had tried to install (with JB Weld on the Imperial-thread adjustable bearing cup for good measure). The Peugeot-branded Stronglight cranks pictured did for a while, but the left was so badly deformed from repeated installations it was nearly bottomed-out on a correctly-sized spindle. So when I found some 49D cranks with Lyotard 460 pedals in the parts bin last week, I went ahead and modified it into a single with chainguard.



The headbadge decal was missing, leaving only a "Made in France" sticker, so I've been trying to fit as many French-made or at least French-branded components I can find. Michelin tires and tubes, Velox tape, Wolber rims, Robergel spokes and Maillard hub front, Mafac brake, Zefal rear fender, Peugeot saddle, Huret shifter, a Simplex downtube clamp I found with the boss filed off that I'm using for a cable stop, a Clement silk sew-up recycled into wraps for the rando bars (I know, I know, actually Italian). The pedals only had one dust cap, so for now I'm running champagne cork cages in their place.


Only new part is a Ritchey headset for the 1" threadless steerer. The only Shimano part is the rear hub, a Nexus Inter-3 with coaster brake -- though I'm building a Sturmey-Archer S3C tricoaster into a Mavic MA 2 and I have an old "Schwinn-approved" trigger shifter from Austria to match the front brake lever.

My "steel" colored enamel touch-up paint actually dried to proper dark sheen, so it's not like I'm trying to hide its age or condition. The hope is it might catch the eye of discerning C&V nerds, but look like just another frankenbike beater to opportunists.

The Golden Boy 

Nice, it looks good, yet sufficiently... purposeful!

oddjob2

Epoxy paints apparently yellows with prolonged exposure to UV.

jacksonwest

Thanks again for everybody's feedback! Have the frame hanging from my stand, curing, and I feel like it turned out pretty well, and should only look better when it's polished. Definitely didn't spray epoxy! Actually ended up using Dupli-Color Professional Enamel, which was pretty straightforward.

After the teardown, wrapped the frame in shop towels soaked with Evapo-Rust 1:1 with tap water and set it next to a space heater in my apartment for, oh, three hours or so. Unwrapped it to find the bare metal was still bare and the dark red "rust" is actually the first coat of primer, since it didn't go anywhere. Also meant more of the frame was still under paint, and under more paint (three coats) than I thought. The worst of the bare metal exposure on the drops also seem to be nickel plated, because was the same color as the spots on the socks where I'm guessing the famous French chrome has worn off. Also much lighter than the other bad spots were, like near the seat post clamp nut, the braze-on housing and clamp stops, the nubs where the pump hooks used to be and the corner edges of the lug joints. I mixed my Testors Model Master Enamel chrome and black to approximate both, and mostly touched up to fill the low spots and smooth the rough edges of the chips. Spent much of Saturday evening and Sunday afternoon carefully spot painting with a 00 brush while I rust blued my forks.



Having given that about 48 hours, went ahead and polished the entire frame, starting with a clay bar, approximately 500 grit Scotch Brite, #0000 steel wool, 1000 grit aluminum oxide on wet paper, a couple of melamine sponges (the 3M erasers were 6 for $4 on sale), Turtle Wax polishing compound applied with a raw wool mitt, then washed it with rubbing alcohol and buffed dry with cotton percale. Finally went over it with a little paint thinner to catch any drips or overpaint from my touch-up and to smooth it in a bit further. While the factory paint wasn't particularly well-applied, it was generously applied -- I found a couple of lumps from overpaint drips on the seat tube and down tube near the bottom bracket. So while I'm sure I lost a little of the stencil work to abrasives, it wasn't much, and I didn't wear through the orange topcoat to the greenish-white undercoat or expose more metal.

The polish looked nice, with the significantly brightened up in both color and gloss, but the paint still got chalky when damp. While wax helped with that, it meant that even polished down the surface was pretty porous and prone to oxidation and moisture retention. Having found a bit of budget, I decided to go ahead and clear coat figuring that it would shed water better once cured, keeping everything brighter and drier. So I masked the rear drops, bottom bracket, seat post and head tube; scuffed up the finish with the steel wool and Scotch Bright back down to a nearly matte finish; did another pass on the touch up with my paint thinner and a final alcohol bath to make sure it was open, neat and clean then headed down to City Paints.



I was ready to buy a proper respirator and the SprayMax 2K Clear, but there was some concern that between the enamel I used for touch up and the possibility the original paint was lacquer, that it would be better to stick with an enamel clear. Which was also cheaper, more straightforward, and considerably less potentially toxic. So I ended up only spending about $10 for two tack cloths and a can of Dupli-Color Professional Enamel.

They've been clearing the rubble from a demolished warehouse a couple of doors down, so I set about setting up my work area while I waited for their dust to settle. First, cleared out a space facing a corner in my building's exposed basement area. Then gave it a spray down with a hose to wet the area to flood any loose dust from the area. Laid an old tent I've lost the poles to as a floor drop, wrapped my stand in plastic wrap, and hung an old duvet for a back drop. Eventually decided to use a coat hanger affixed to the drops and a pipe in the ceiling to get the work as high off the ground as possible. Ended up hanging vertically, first from the drops, eventually from the coat hanger run through the head tube--horizontal would have probably been easier, especially if I could have rotated it on the BB spindle axis or lifted it easily.



Checked with the demo crew to confirm they were done, and while I was pretty nervous, eventually got around to painting. One last alcohol rubdown and dry with a microfiber cloth, a tack cloth for dust once the frame was hung in place, shook the can for a good minute, did some test sprays, then applied a very light coat by holding the can near the back of its range (10" or so) and letting the frame "get in the way" as I weaved the upright can back and forth. Day couldn't have been better for it -- 65 degrees with 72% humidity -- so I inspected my work for overspray using a very bright LED bike light and gave the first tack coat 15 minutes to flash. My goal was to fit four coats close to within the recommended 1 hour recoat window (though I think you have an hour after each coat to re-apply, give or take, I also wanted to limit bug exposure and get the work done before neighbors started getting home and knocking about or asking awkward questions).

No tack cloth for the second or following rounds, and not much heavier of a coat than the first, another 15 minutes to flash. Third coat was shot for longer and at closer range, and was possibly the heaviest coat. Gave it 20 minutes. Inspection revealed no drips, just a light dapple of overspray. Final coat I rotated the frame 180 degrees and finished the can, paying particular attention to the head tube and the lug joints that were now more accessible. I was probably wasted a good deal of paint as I overshot on the passes across target, but I figured better than getting hot spots by starting the spray on target or trying to strafe a straight line down a tube. In the future, might see about a different nozzle than the default fan tip.



Once the spraying was done, hung the frame back on the stand and then tented it all with the back drop. Left it an hour, then brought it indoors to hang by the masked drops before opening all the windows in the apartment and heading to a volunteer shift at the Bike Kitchen. Instructions said it would be safe to handle after an hour, but besides a quick check to make sure it wasn't still tacky, waited until after I got back home to try running a finger over it. There's a bit of dapple from overspray, and you can feel the depressions over the deeper chips, but it's definitely smoother overall. And much more shiny! What dappling there is also seems to be confined to that from the last coat -- presuming any from early coats were leveled by later ones.


According to Dupli-Color, I can cut it level as early as Friday morning. But I still have a big tray full of alloy components to wet sand, plastic bits to buff and bars that should get a proper French Polish before I can shoot any centerfolds, so it'll probably be more like Monday. Luckily I have two days of actual work to keep me busy enough to forget my impatience.