K2 / Proflex Riders Group
General => Tech Forum => Topic started by: JPSeuropa on September 20, 2007, 05:17:35 am
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I went out for my noontime ride and the seatpost tube to toptube weld failed and the seatpost tube tore out...
Now I know what that creak was.
I may consider getting it welded back together. What is the frame material? Otherwise, it is new bike or frame time. I am too upset about it all at the moment to be rational...OK, I am never completely rational.
SOOOOOOOO Sad...................
So many rides, so many memories....sniff.
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Deepest sympathy mate,always sad when your bike dies.Maybe you can repair it though.
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Ouch ouch ouch.
If you're in the states, Terry (Shovelon) is a terrific aluminum frame welder who will do right by you on quality and price. (I bet!)
If you don't want to fix it, I really need a rear ODS shock - or equivalent - for my "good" 856.
Alternatively, I'll sell you my "good" 856 sans a rear shock.
Third alternative, there's an 856 frame on ebay, but the price is kinda high.
Regards, Will
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You can try www.craigslist.com for the cities near you. There are a 756 and a 856 for sale near me for a decent price so you may find one near you. Search under not just proflex but pro flex, girvin, noleen. You never know quite how the seller will have it listed. If you don't have any sucess with repairing it.
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what size is it? Is it interchangeable with an 856 main frame?
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I went out for my noontime ride and the seatpost tube to toptube weld failed and the seatpost tube tore out...
Now I know what that creak was.
I may consider getting it welded back together. What is the frame material? Otherwise, it is new bike or frame time. I am too upset about it all at the moment to be rational...OK, I am never completely rational.
SOOOOOOOO Sad...................
So many rides, so many memories....sniff.
Oh man! It is the creaking season for sure!
Is it a clean break? Or is it torn enough to require refitting? I can tell you how to prep it, and what to say to to a welder for a repair if you like. Should fall under the shop minimum charge then. I have a weld mandrel that I can lend you too. It helps keep the shape during welding.
Terry
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As for the aluminum, it's a 7005 alloy treated to T6.
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70 series is typically not a good material to weld are you sure it's not 60 series? 50's and 60's are your 2 typical manufactured favorites for strenght and weldability. Not saying 70 can't be welded but it would make no sense for strength.
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You got it backwards actually. 7005 is not 7075. 6061 can be welded but should have a re heat treat to regain it's optimal strength.
7075 is a heat treatable, high strenth aluminum with poor fatigue resistance. 7005 on the other hand is a proprietary alloy designed by Easton sports for thier arrow shafts. It can be manipulated and welded with little loss in fatigue resistance. In fact, when welding, the heat affected zone will deharden, then upon cooling reharden itself by means of strain(distortion) hardening. A post stress relief usually follows with a 400 degree F. bake(powder coat), but a simple stress relief by means of letting it sit un restrained for a week or more is OK.
7005 alloy is wonder alloy. Go to the Easton web site for welding information.
Terry
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dead interesting reading all of this. I always got the impression that 7005 was inferior as it was easier to manufacture and it appears on the cheaper end bikes while 6061 was superior as harder to use and appeared on higher end bikes... also 6061 seems to have thinner walls and thus I was assuming it to be better (like steel).
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6061 is better, if the expense was put into it. Like the very high end bikes, or boutique bikes so to speak. The difference is that while 6061 can be formed, welded to a much higher extent, it has to be done while soft, or softened, then heat treated to T6. Very few manufacturers have thier own furnaces for heat treat, so all the goods have to be sent out. Not cheap, and restriaghten process is time consuming.7005 on the other hand can be bent, or minimaly formed, welded, and it will return to it's so called T6 hardness. Magic eh?
Ok, the deal is that Easton in thier infinate wisdom has shut out the U.S. and Canada, and ther rest of the world from econonicaly manufacturing with 7005, except for Communist China and Taiwan. I have contacted many extruders, and they don't want to get into legal hassles with Easton. The Chinese have a strangle hold on Easton, so they have driven 7005 into the crap bikes that you and I see everywhere. No wonder they own the crap bike market. Now they are going after the carbon market, if they already have not conquered that too.
Great, so now we can't compete, so why try. 6061 is a great aluminim, just more expensive to work with, and tricky to weld without detempering the life out of it(but can be done if you know how).
I go through 30,000 lbs of aluminum a year, not 1 lb of it is 7005. I could triple that if I had access to 7005. GRRRRRR!
Ok, my rant must come to an end.
Terry
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jeez... things that go on without our knowledge!
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There is something about the physical properties that make 7075 better when it's in the harder states like T6, T61 and T8 that makes it more durable than 6061. In the Aircraft industry we will not weld a 70 series because it will crack back our in the wrong circumstances. Now 7005 on the other hand still has the same refining process and since I don't know much about it I can not comment. Time to do some research. ;)
17yrs a Machinist / Welder I haven't used it at all. Most my work is with 2024, 5052 and 6061. We do some parts in 7075 as well. I LOVE machining 7075 T6 and harder.
Terry thanks for the 411!
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So the wife says " Go get a new bike" so I did. I bought a leftover 2007 Specialized FSR Pro. I owe her big time. I will bring the Proflex back to life at some point though. I have to finish building my Locost first though.
Can I still visit this site if I am riding something else?
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What a cool thread!
Amazing tech stuff written so even us "Marketing Types" can understand it...
JPS, as far as I'm concerned, if wrecking a Proflex was "A Worst Day Ever" you can post here for ever. (FWIW)
Now if you start parting out the 857 let us get a first look before eBay!
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Well, this will come as an offtopic, but does anyone has the "Easton Custom - Exclusively made for Pro~Flex"... thing, that was glued in the frame and doesn't need it anymore? I have a K2 frame, and it doesn't have it.
But I would like to...
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I LOVE machining 7075 T6 and harder.
!
I know what you mean. Nice chips, hardly any burr. Kind of like 303 SS.
Terry
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Decided to build up another frame with all my bits from the Proflex. So the the Risse, rear swingarm with bearing mods and Hammerhead are for sale in the "For Sale" section.