Help--brazing onto to a chromed frame
11-16-23, 02:53 PM
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Help--brazing onto to a chromed frame
Hi all,
I'm just starting out, and my primary interest is mostly modifications to older frames.
I have a 1976 Centurion Semi-Pro (full Tange Champion #1), and I'm pretty sure it's fully chromed under paint (we'll find out soon enough). I've been kicking around the idea of stripping the paint and adding a few modifications: 2 or 3 water bottle mounts, a mid-fork mount for a front rack, and maybe DT cable stops to reroute the cables under the BB. Yes, all of these can be clamped on, but the silkscreened decals are largely gone and the paint is in rough shape anyway, and it seems a great frameset for a restomod/repaint to give it a new life as a randonneur/credit-card tourer.
Are there issues with brazing onto a chromed surface; e.g., do I need to remove the chrome, or are there any other major considerations I should know about before modifying a chromed frameset? Thanks!
I'm just starting out, and my primary interest is mostly modifications to older frames.
I have a 1976 Centurion Semi-Pro (full Tange Champion #1), and I'm pretty sure it's fully chromed under paint (we'll find out soon enough). I've been kicking around the idea of stripping the paint and adding a few modifications: 2 or 3 water bottle mounts, a mid-fork mount for a front rack, and maybe DT cable stops to reroute the cables under the BB. Yes, all of these can be clamped on, but the silkscreened decals are largely gone and the paint is in rough shape anyway, and it seems a great frameset for a restomod/repaint to give it a new life as a randonneur/credit-card tourer.
Are there issues with brazing onto a chromed surface; e.g., do I need to remove the chrome, or are there any other major considerations I should know about before modifying a chromed frameset? Thanks!
11-16-23, 04:11 PM
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Yes I think you will need to remove the chrome. Certainly you would for welding. It will also produce somewhat toxic fumes. So remove a bit more than you need, wear a respirator, and keep the place well ventilated!
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11-16-23, 05:52 PM
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IIRC silver brazing to chrome is OK and if done properly non toxic. But some braze ons like bronze filler more, and for that you'll need to remove the chrome. What you do to refinish will also have some influence to how you deal with the chrome plate.
I had a 1972ish Fuji Finest which was fully chromed under the paint. In my youthful dream eyes I stripped off the paint thinking I would have a shinny chrome frame. What I had ended up being a dull and in places rough surfaced chromed bike. The effort to remove the really thick layers of primer/paint from the rough surfaces was nowhere near balanced by what it looked like after. I hope you find a nicer under the paint condition that I did. Andy
I had a 1972ish Fuji Finest which was fully chromed under the paint. In my youthful dream eyes I stripped off the paint thinking I would have a shinny chrome frame. What I had ended up being a dull and in places rough surfaced chromed bike. The effort to remove the really thick layers of primer/paint from the rough surfaces was nowhere near balanced by what it looked like after. I hope you find a nicer under the paint condition that I did. Andy
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AndrewRStewart
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11-16-23, 06:52 PM
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I asked a framebuilder about replacing a broken cantilever posts on a chrome fork. He's said I could do the prep work, but as I remember he wanted all the chrome removed 2" back on both sides from where the the post was going. I assumed the way to remove it is with sand paper, outside with a mask, gloves and down stream from the tomatoes.
11-17-23, 12:17 PM
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A set of files would probably work better for chrome removal than sandpaper. Just avoid gouging deep into the steel tube. I wouldn't be overly worried about toxicity of the chrome particulates, so long as you do not snort them, vaporize, or dissolve in solution the solid material fines should be fairly inert.
Brazing over chrome (with silver) seem structural questionable, I have seen plenty of chrome flake-off of the base steel tube in large chips. If you braze to bad chrome then the connection is only as strong as the underlying strength of the chrome/steel bond.
Brazing over chrome (with silver) seem structural questionable, I have seen plenty of chrome flake-off of the base steel tube in large chips. If you braze to bad chrome then the connection is only as strong as the underlying strength of the chrome/steel bond.
