# Aluminum heat treating/aging



## pvd (Jan 4, 2006)

So...

I was planning and preping to do a 7005 hardtail as practice before doing some honest FS bikes. I've basically given up finding that the only choices available to a tiny builder are just lame. Basically nobody in the US makes 7005 and it all has to be imported from taiwan. Easton offshored everything a few years ago.

Now I'm changing material to 6061, which gives me zillions of choices of stock, but puts the whole quenching and aging front row center.

I spoke to my local heat treater (http://www.garnerheattreatinc.com/) and picked his brain and shopped pricing. This was the only place I could find with ovens and baths large enough for bicycles. It's going to cost around $400 per run. A run will be anything from 1 to 10 frames. 3 at a time will be a strech for me and will really limit testing and prototyping possibilities. Also, a holding fixture will need to be fabricated for each frame going through the process.

After quencing in the fixture I need to pick up the frames, the frames need to get alligned then returned in the fixture for heat treating/aging. Time consuming to say the least.

I would love some input from people that have gone throught this process.

Fixturing examples?

What temper did you go for?

Can test rides be done prior to heat treatment with minimal risk to body or bike?

Ever mix 6061 and 7005? (literature says it's a no no)

What kind of deals are you getting and by who?

Have you broken the rules and how did it turn out?

see also:

http://www.eastonbike.com/downloadable_files_unprotected/fab_instr/fab_instructions-7005_6061.pdf


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## coconinocycles (Sep 23, 2006)

pvd said:


> So...
> 
> I was planning and preping to do a 7005 hardtail as practice before doing some honest FS bikes. I've basically given up finding that the only choices available to a tiny builder are just lame. Basically nobody in the US makes 7005 and it all has to be imported from taiwan. Easton offshored everything a few years ago.
> 
> ...


paul sadoff has all his al. stuff done in santa cruz, and i think the company does a great job {from paul's testimony} and is affordable. i saw some polishing they did too, and it was top notch. as a side note, at the aluminum whitewater raft co. i worked at, we MIG'd 6000 series bent corners that had been expanded as well to accept 7000 series straight sections, but it's apples and oranges, this stuff was 2" x 1/4" kinda material.


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## klondikebike (Jul 11, 2006)

Out of curiosity, why not stick with the Easton 7005 tubes Nova sells? Then you can just stick with the simpler heat treating.
They seem to have a pile of stock in both alloys.
Anyone know why the 7005 alloy in the Easton tubes IS weldable, but a lot of the literature you see states that most 7005 is NOT weldable.
You look at the prices of the Easton main tubes; like $20.00 for a DT as opposed to 30-40 and up for steel. Makes the whole heat treatment thing start to look appealing...
Find an old electric pizza oven, get some good PID type controls and sensors, bingo, heat treatment.


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## pvd (Jan 4, 2006)

I have bought a lot of 7005 tubes and stock, of what is available. While it is possible to build a bike using these parts, the bike will not be up to my standards. I am very specific about what I want and how to do it, that's why I started framebuilding. I want it EXACTLY the way I want it. What is available of 7005 for small fries will not do this for me.

6061 will provide the opportunities I need. It's just the heat treat that I need to work out.


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## BrendanC (Aug 11, 2005)

As you point out, 6061 can be less expensive if you're running a good batch size.
I've done a few 6xxx frames & sent them to a heat treating outfit that has done bikes before, such as http://www.newtonheattreating.com/ Quite a few smaller companies (and bigger ones, too) have used them or are still using them. You may even have them do the straightening for you.


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## dr.welby (Jan 6, 2004)

When I was at UC Davis we got our HPV frames heat treated by Ventana. I don't remember if we piggybacked on one of their runs or if they do it in-house, but if anything you might want to see what they're doing. At least they're pretty close to you.


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## klondikebike (Jul 11, 2006)

You would "probably" be safe on an un-treated frame set for test pilot purposes. It won't fail catastrophically right away , keep an eye out for cracks developing while you hone the design. Just wear a full face and a Dainese!:thumbsup: 
Whats Eastons minimums?
Getting back to the 6061/heat treating biz. I used to make Al and CroMo suspension components for mountain snowmobiles. The Al components were 6061, usually 1" sched. 40 and thinner A-arms etc. The tubeing would bend long before i would get cracks developing, and they weren't heat treated.
Once you get the design nailed down, more or less, you could then build up the prototype, get it treated, and test to destruction:madman: 
Yeah baby yeah!


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## Thylacine (Feb 29, 2004)

Pete,
I can offer a little bit of insight here. Experience was limited, but it was a great learning experience and good to experience firsthand all the proceedures when dealing with a material I didn't have much complicated fab'ing experience with short of machining the stuff.

"_After quenching in the fixture I need to pick up the frames, the frames need to get alligned then returned in the fixture for heat treating/aging. Time consuming to say the least."_

When I did my FS bike, I solutioned it off the jig and then artificially aged it in a fixture. The thing that freaked me out the most is that the billet moves more than the tubing does. In the end, I didn't fixture the shock mount because it had 'grown' about 1.5mm forward, so I just made sure the main pivot to the dropouts were square to eachother and left it at that, fixtured it, and the chucked it in to be aged.

_"Can test rides be done prior to heat treatment with minimal risk to body or bike?"_

6061 is as soft as butter prior to heat treatment, so I wouldn't. but Klondike seems to have had limited success with it so who knows?

_"Ever mix 6061 and 7005? (literature says it's a no no)"_

It's completely possible. The heat treater we used was very open minded and creative, and when we looked at both the graphs there was a point in the solution cycle where both alloys reached a good compromise point. Not having spent the last 25 years heat treating stuff, I naturally only understood about half of what the guy was saying, but it made perfect sense at the time and 5 years later the frame is still bomber.

Having said that, I wouldn't do it in a production setting, but for prototyping I'd do it in a heartbeat.

Aluminium is a whole new kettle of fish, Pete. Have fun with it!


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## BrendanC (Aug 11, 2005)

I'd add that if you're going to cheat a bit with mixing the alloys, treat the frame as if it were all 6x, ie quench the 7x along with it. I've seen this done in prototyping many times without a problem. In fact, I rode a 6x bike with a 7x BB shell for months before hanging it up. There was nothing wrong with the bike at that point.


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## klondikebike (Jul 11, 2006)

To clarify, the Al i used was T-6, but i did not heat treat it after welding, and had no issues later on around the HAZ.
Obviously nobody will build a frame out of 6061-T6 material, but even the Easton bike tubing _*should*_ hold together long enough w/o heat treatment for a designer to get an idea if the design "works" and warrant a prototype with heat treatment.
I still keep my eyes open for a used electric pizza oven. Assuming the stars lined up right, i figure a guy could get the heat treatment equipment for 7075 for under a grand. Its a pretty straight forward process really.


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