umi

Hi guys!
I just bought this old road bike that needed a new paint job, so
after blasting it i discovered it is beautifully built. I checked out this forum and it seems it is not uncommon people want to keep the bare metal look. What are my options? I cannot braze but i know the guy who can, i guess if i try to get brazed the entire frame, it would get twisted, old brazing would get loose and it would never coat thin and even, am i right? I don't want to chrome, don't like the look of it. Gibbs wouldn't work either for outdoors it seems, any other option, silver, gold? I bought clear primer in rattle can but this is my last option. Sorry for a long post.
Cheers

Falanx

Have a look around your local area and see if there are any small finishing shop businesses that can phosphate it for you?

Buy a very, very zinc-rich primer and put down a few good coats, then polish the primer - if you're above about 85% zinc in the finished layer, the paint will polish like pure metal but it's an intensive job.

Otherwise, be prepared that if you clear-coat a steel frame, it will begin to corrode under the clear coat, and sooner than if you'd got primer and paint between the steel and the gloss.

randomgear

Falanx, Wouldn't you still need to clear coat the zinc? Without a coating I would expect zinc to oxidize just like hot dipped galvanizing. I also think that many manufacturers recommend a coating over any zinc-rich primer that is less than 94% zinc in it's dry state.
The zinc-rich primer would also cover up all the brazing that I expect the OP would still want to see.

lverhagen

I have heard of oiled steel being fairly resilient and resistant to corrosion, but the process for achieving a truly "oiled" finish is time consuming. Basically, you wipe down the entire frame with a light-to-mid weight oil pretty much every day over the course of a month or so; in this time, a light oxidized patina will form from very light rust. This light rust holds oil much better than regular bare steel, so the frame can be wiped completely free of surface oils and enough will be left behind, impregnated in the steel.

I have never actually taken this approach myself, but i have heard of it and seen it and it seems like it might be worth a shot sometime. Good luck!

Cheers
lverhagen

Falanx

My bad, yes. I meant to explicitly state clear-coating over the zinc.

However, yes, without good masking, it wouldn't expose the brazing filler. I'm always verywarey of intentionally exposing galvanic couple sin load-bearing structures.

fietsbob

Consider having it plated, Brass, an alloy of Copper and Zinc will not electro plate,
but copper, an elemental metal will plate steel readily.
then you can have the copper given a patina treatment.

lverhagen

Or you can pee on it.

But seriously, electroplating is your best bet if you want a metal coating on your frame.

Cheers
lverhagen

ftwelder

My painter does spray metal arc coating or something like that. "longwoodsmetalfinishing.com" 'pretty amazing process. I have seen his restore the metal to car bodies that were so badly rusted they looked like lace and regain a decent surface.

Falanx

You can plate alloys. It's done all the time. Bliss plating offer it not far from you, and that's about ten seconds with Google.

umi

Hey guys, thanx for all your answers!
The frame is going to get zinc plated on monday, then sprayed transparent primer and then 2k semi gloss- that should do.
Right now i got another problem, don't know if i should start a new topic on this..
Brake bridge was messed around (lousy welded) so i removed it. As i'm fitting hydraulic rim brakes i don't really need it.
So the question is: is structural integrity really compromised without it?
It's ugly plate type, can i get brazed in some tube instead of it?
Thanx

LesterOfPuppets

Zinc Phosphate? Or Zinc with a chromate conversion layer? Zinc with chromate doesn't really need clear coat although I guess that would help with fingerprints.

All this for a cheep-o bike? Wow!

If it's a small frame and you're a light rider I'd just clean up the area with a file and ride without. Hydraulic rim brakes? Like Maguras? Are you getting some Canti bosses welded on also?

And I'd Framesaver the frame. Even though Zinc and Zinc phosphate are rust preventatives it's tough to get all the pickle out of the chainstays, etc so they maybe vulnerable to rust.

umi

I will try to get conversion layer, will see on monday what they can do, if it comes out really good then i won't paint it.
I'm light, brake bridge is history
I'm about to weld canti bosses with stainless on 'middle' stays (there are stays between seat and chain stays) for HS33.
Yep, all this for a bike i paid 35 euro!!!
Anyway, anybody ever heard of barbican? That's what decals said.
I will post a photo when finished.
Cheers

Falanx

Zinc phosphate is deposited as a salt from a bath, not as a metal, and is soluble in even slightly-basic water - like road salt-contaminated rain spray, for example. Zinc chromate is horrible, nasty, toxic and water-soluble stuff, that's why they use it for etch priming aluminium in the UK, but zinc metal with a chromate conversion layer is relatively safe - it converts to a chromate hydroxide which is insoluble.



If he's getting it *zinc* plated, not phosphated or chromated, then the pickle solution will be washed out by the zinc plating solution and zinc will go down on the inside of the tubes, too. That's how all plating systems work. There's only an issue if the plating bath of a metal deposit is acidic, the deposit metal or alloy is cathodic to steel and then the solution not properly rinsed off.

LesterOfPuppets

We often had troubles with intricate tube structures (like a bike frame) on the zinc line. If bubbles are trapped in the frame while in the zinc tank then those areas are prone to rust. I never ran any parts that didn't get chromate after zinc. Some clear chromate, some yellow. Zinc plate will quickly oxidize without a conversion layer.

The worst was these shopping cart guards we did for grocery stores. They were 6" diameter and 20' long with a 1" hole on either end. It took forever letting the contents drain out and you had to rinse two or three times after each tank. No matter what you still had stains from a nasty combination of solutions dripping out. We ran three stacked up on either side of the rack. Totally wrecked the tank solutions too.

It's been a while but IIRC the zinc bath was acidic (pH somewhere around 3 perhaps, oh my I'm really stretching the brain cells here). I know I had to dump a BUNCH of boric acid in there from time to time.

LesterOfPuppets

Oh, I also did zinc phosphate on my line. Yep, no electroplating there. It was usually done as a primer, not a final finish.

Falanx

Did you not have any way of agitating the frame in the solution, or some heavy-duty wetting agents in the tank? I assume there was a mixer/aerator somewhere in it but that's hardly perfect for ensuring the solution entering the tubes is under pressure or well mixed and feeding through one hole and out the other...

Most plating shops I've seen tend to let the part just hang in solution, but they tend not to be tubular... It's almost owrth it if you'r egoin to do a lot of such work, to find a method to keep agitating the workpieces and almost forcing solution through them...

Wulf

Get some Cold Blue at a gun shop and blue it. It becomes somewhat resistant to rust like a phosphat coating. Or Parkerize it.

umi

Just a quick update.
You know that feeling when you want to get something right, but you go too far into unknown thinking you can do better than it's done...
Well i welded canti bolts in place with inox for strength and then tried to get the welds brazed for extra sleek look. Big mistake! Apparently you can NOT braze inox. If only i knew. Now it looks extra tatty. Same thing happened on two small holes, seat stays and fork. Tomorrow it finally goes on galvanization, with my luck zinc probably won't stick on inox either. N.B. lesson learned: brass and inox hate each other!

Cassave

INOX is a generic term for corrosion resisting steel if I'm not mistaken. I haven't encountered a stainless alloy that couldn't be brazed assuming use of the right flux.
Perhaps you didn't flux the weld area you were trying or braze over?

umi

I used borax...is there something better?

Falanx

I wouldn't do either, They're intended for gun barrels. Firearms tend not to be ridden through muddy puddles and left in a garage.

umi

Guy in galvanising business did it in no time and free of charge, i had to pursue him to take some money. He also told me it's not durable enough for outdoor, that i have to clear coat it. So i did, another good thing is that clear removes that pink-greenish opalescent glow so it looks more like brass. This is before clear coat:

It may look girlish and flashy for now, but it's not finished yet...

Allen

I have to admit that looks better than I thought.
Nice frame.

randomgear

Wow, that"s purdy! Now what are you going to do for components, polished, clear or color anodized?

umi

Thanx, i got this special translucent yellow glass paint i will try on maguras, also will get cnc cut brake boosters out of brass plate, i made really nice brass mudguards today. Other trash components will probably be matte black. It would be finished already but i got some exams this week...