Aluminum frame modification/repair - is it possible?

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prendrefeu
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by prendrefeu

Hello,

I've been holding on to a fairly rare aluminum frame for a long-planned build, but at a bit of a crux, hoping I can get some ideas or insights from the community here. The frame itself has no structural damage, no signs of cracking and is in overall great condition, but it is fairly rare so getting any information - at all - from the manufacturer has been akin to talking into a cave.

Without getting into details, at one point it suffered a little scrape-up, so the surface on a chainstay and on the outer lip of the BB shell were gouged or scratched. Right now there is a bondo-smooth-out on that area, but I'm hoping to remove the bondo and find a way to smooth it over.

Questions -

-Can minor gouges/scratches into an aluminum frame be filled in and then smoothed out? The frame needs to be polished as part of its ultimate finish process, so painting over these things is not an option and it needs to be as continuous of a surface as possible.

-The frame currently has external cable routing. Is it possible to add internal routing points to the frame?

-The frame is currently traditional in having the rear brake on the seatstays. It would be great (for this frame's shape) to have a brake mount placed below the bottom bracket, similar to what a few TT bikes do. Is this possible?

...and, finally, for any of these things, do you have a recommendation of someone to send it to? There are a few welders in my area although they seem to specialize in automobiles not bicycle frames, and the majority of frame builders in Southern California (however scarse they may be) specialize in steel.

Thank you.
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stella-azzurra
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by stella-azzurra

Q1 = yes you can clean up the area and tig weld new aluminum. It depends how deep the scratch is.

If they are not deep then http://www.youtube.com/watch?v=-jM-5qNb6sw


Q2 = no you would have to take the frame tubes apart
Q3 = yes you can

someone that knows how to use a tig welder can do this.
I never took drugs to improve my performance at any time. I will be willing to stick my finger into a polygraph test if anyone with big media pull wants to take issue. If you buy a signed poster now it will not be tarnished later. --Graeme Obree

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fa63
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by fa63

Contact Joe at Tsunami. He will tell you straight up whether or not these can safely be done, and give you a price if he can do it. Shipping from California to Arizona and back shouldn't be too bad either.

boolinwall
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by boolinwall

Depends on the aluminum. If it's 7000 series. No biggie. Just be careful and keep in mind that the tubes were butted for the welds to be where they are. If it's 6000 aluminum. Not likely. Any weld, no matter how insignificant, will require heat treating and aging afterwards. Basically, if the aluminum has "T" rating after it, you shouldn't try to weld it. for example 6061 "T"6. I believe, but don't quote me on this, that the 2000 alloys that principia used also require an after weld heat treatment.

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prendrefeu
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by prendrefeu

Thanks for the replies everyone.

@Boolinwall is there any method to determine what aluminum was used? I've tried calling up the mfg but it seems like anyone who works there now can be bothered to give an answer, most I've spoken go blank when I tell them that their company once produced a great road frame. (Emphasis on once).
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boolinwall
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by boolinwall

Whenever I'm stuck. I do a google search. You can usually turn up abit of info. What kind of frame is it?

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prendrefeu
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by prendrefeu

Santa Cruz Roadster.
Rare. Near-pristine condition. Except for those scratches/gouges. :lol:
Google search reveals a lot of forum posts circa 2004-2006, but I haven't spotted what type of alloy was used.
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stella-azzurra
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by stella-azzurra

I never took drugs to improve my performance at any time. I will be willing to stick my finger into a polygraph test if anyone with big media pull wants to take issue. If you buy a signed poster now it will not be tarnished later. --Graeme Obree

boolinwall
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by boolinwall

So yes. If it is in fact 7000 series, you should have no issues moding it. Just don't ride it for like a month afterwards. 7000 alloys take about a month to cure after welding.

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prendrefeu
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by prendrefeu

Thanks stella, must've missed that forum thread.

I'll have it mod'ed and let it rest. This is going to be a very, very slow build as I'm in no rush for yet-another-bike in the stable and I want to make this one really special with a lot of custom parts to it, many of which I hope to be making myself in my own workshop. I'm excited. You could say I'm stoked. :twisted:
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boolinwall
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by boolinwall

As for the scratches on the chainstay, I wouldn't bother traumatizing the alloy over them by re-heating them to the point of melting (welding for example) On most alloy frames, the tubes are twice as thick in that area. It's done for two reasons. 1. Chain suck. It's bound to happen at some point. 2. It's a tough section to weld correctly. Look at frame cutaways. The chainstays around the BB, the seat tube around the top tube junction and the downtube at both junctions are usually pretty beefy, but nowhere near as thick as the around the chainstay. I once read that the most traumatizing thing a metal frame will ever go through during a normal life, is being welded. I wouldn't do it twice for no real reason.lol

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HammerTime2
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by HammerTime2

Try PM'ing Wildabeast. He's apparently had at least 3 of them, so maybe he knows.
In What's your worst purchase?, Wildabeast wrote:Santa Cruz Roadster road frames- Ripped the bottom bracket out of 3 of them, the first resulted in the only crash on the road in 15 years of racing. 14 stitches in my right knee from the chain ring. The other 2 failed while leaving stop lights.


Well, he hasn't logged in for a year, so who knows.

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stella-azzurra
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by stella-azzurra

Yeah that guy eats frames for some reason. Last time I knew he was looking for custom steel. I don't think it will happen with Prendrefeu
I never took drugs to improve my performance at any time. I will be willing to stick my finger into a polygraph test if anyone with big media pull wants to take issue. If you buy a signed poster now it will not be tarnished later. --Graeme Obree

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prendrefeu
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by prendrefeu

:lol:

Yeah, I don't think I'll be ripping out the BB shells with my enduro-climber power output. And Wildabeast apparently went through bikes and parts like Chris Hoy trying on skinny jeans in the shopping mall. The first run of Roadsters had some reports of problems, later runs (my frame is, I believe, a later run) are still going to this day.

The build - whenever it gets done as there is no time limit - will be purely for local rides up to 62mi and mostly flat or rolling terrain and those occasional 'holiday' club rides where everyone brings out the fancy bikes.
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HillRPete
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by HillRPete

Off topic, sorry, but if it's such a rare classic, why would you mod it?

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