AndrewG Posted January 3, 2012 Report Share Posted January 3, 2012 Hi. It was spring 2011 when I cracked my GU TP08 ... I give it to welder in aughust. I rode it just for 2minutes and frame was again cracked near new weld. I have read a lot of things about welding this material. it´s U6 which mean 6066 with T6 heat treatment. I have learned that it need to be after welding again heated for 130°C I think . I ask teachers from my school if they know about someone who could do this but they didn ´t know.... So I need to ask if it will be possible to heat this frame in big oven for ceramic ? and for how many hour it´s need to be heated ? few od my friends have welded frame (koxx,ZOO!06,KOXX SKY) and they´re all ok. I think 06zoo! should be made by same method as mine GU. So maybe problem was in welder who used wrong method, or did something wrong ? what you think ? Only reason why I want to weld this frame is that it´s prettiest frame ever made imo and it have thick tubes so it´s not problem to weld it.(frame is cracked behind BB part where tube is welded to this CNC part...) Quote Link to comment Share on other sites More sharing options...
FamilyBiker Posted January 3, 2012 Report Share Posted January 3, 2012 throw it away and get yorself a crmo frame with the same geo from marino. rode mine for 2 years now(have 92kg),still going strong like on the first day. marinos weight like 2.100g. just my opinion Quote Link to comment Share on other sites More sharing options...
AndrewG Posted January 3, 2012 Author Report Share Posted January 3, 2012 marino is´t look like GU that´s the problem Quote Link to comment Share on other sites More sharing options...
The Mechanic Posted January 3, 2012 Report Share Posted January 3, 2012 marino is´t look like GU that´s the problem If the welder used the wrong kind of welding rod that would cause that problem filling material needs to be correct, also all joints to be welded need to be meticulously cleaned. I assume he TIG welded it. 1 Quote Link to comment Share on other sites More sharing options...
FamilyBiker Posted January 4, 2012 Report Share Posted January 4, 2012 (edited) If the welder used the wrong kind of welding rod that would cause that problem filling material needs to be correct, also all joints to be welded need to be meticulously cleaned. I assume he TIG welded it. and,especially for u6 and other treated stuff,the welding area would get hardened through the welding heat and needed to be u6treated again(whole frame of course) isnt worth it...sorry Edited January 4, 2012 by FamilyBiker 1 Quote Link to comment Share on other sites More sharing options...
ghostrider88 Posted January 4, 2012 Report Share Posted January 4, 2012 and,especially for u6 and other treated stuff,the welding area would get hardened through the welding heat and needed to be u6treated again(whole frame of course) isnt worth it...sorry This was the problem I guess. Quote Link to comment Share on other sites More sharing options...
FamilyBiker Posted January 4, 2012 Report Share Posted January 4, 2012 (edited) if marino can build this kind of top/downtube area,he sure can build a gu tp replica.ask him.tell him peter told you edit:if you heat treat a frame yourself and dont know EXACTLY what you´re doing you´ll produce a frame made of emmentaler cheese...lol Edited January 4, 2012 by FamilyBiker Quote Link to comment Share on other sites More sharing options...
Luke Rainbird Posted January 4, 2012 Report Share Posted January 4, 2012 Peter, whilst I've got a fair bit of respect for Marino and his frames, you really need to realise that there's a time and a place. A Marino frame isn't necessarily the perfect solution for everyone, stop preaching as if it is. If you want a cheap, reasonably decent steel frame then they're great but that isn't what the OP is looking for. Horses for courses and all. Quote Link to comment Share on other sites More sharing options...
FamilyBiker Posted January 4, 2012 Report Share Posted January 4, 2012 just thought about what a new gu tp frame would cost,around 400eur?mr.alegre does heat treating in the near future,so it hasnt to be called cheap anymore.his weldings are amazing. didnt mean to do commercials here,was just a tip and the answer for the "doesnt look like gu"-post. wont say marino again now. promise greets 1 Quote Link to comment Share on other sites More sharing options...
ghostrider88 Posted January 4, 2012 Report Share Posted January 4, 2012 if marino can build this kind of top/downtube area,he sure can build a gu tp replica.ask him.tell him peter told you edit:if you heat treat a frame yourself and dont know EXACTLY what you´re doing you´ll produce a frame made of emmentaler cheese...lol I actually like that white frame(might have something to do with the V-brake posts),what was the price?A I can´t find the pricing at his webpage anymore. Quote Link to comment Share on other sites More sharing options...
FamilyBiker Posted January 4, 2012 Report Share Posted January 4, 2012 cheap(mild)steel:120 usd 4140CrMo:250usd plus shipping,depends on distance from peru.i paid 65 usd shipping. forgive me,luke,but he asked Quote Link to comment Share on other sites More sharing options...
ghostrider88 Posted January 4, 2012 Report Share Posted January 4, 2012 cheap(mild)steel:120 usd 4140CrMo:250usd plus shipping,depends on distance from peru.i paid 65 usd shipping. forgive me,luke,but he asked And that frame is actually yours?I would like to see it builded Quote Link to comment Share on other sites More sharing options...
FamilyBiker Posted January 4, 2012 Report Share Posted January 4, 2012 (edited) not mine,just for example mine is the "Kamel" is from a peruvian guy http://marinobike.blogspot.com/2008/07/marino-kamel.html Edited January 4, 2012 by FamilyBiker Quote Link to comment Share on other sites More sharing options...
Rob Leech Posted January 4, 2012 Report Share Posted January 4, 2012 Posts 10 and 12, not saying it again, lol. Cheers, Josh. 1 Quote Link to comment Share on other sites More sharing options...
AndrewG Posted January 6, 2012 Author Report Share Posted January 6, 2012 (edited) thanks for your repply guys. I´m pretty sure that it cracked again because of that t6 heat treatment which was needed here could someone tell me what temperature is needed and how many hours frame must be inside of oven or how to call it ? I found something The coats were subjected to a two-stage heat treatment. In the first stage, the coats were held at a temperature of 420 °C in a laboratory furnace in the air atmosphere for 2 hrs, and then quenched in water at room temperature. Rapid, non-equilibrium cooling of the AlSi alloys causes its supersaturation (solutionizing). Supersaturation means an enrichment of the solid solution Al(Si) in silicon and reduction of the share of large Si crystals in the bulk of the coat, being the result of a shift in the solubility limit line in the Al-Si phase equilibrium system (Fig. 1). In the second stage of heat treatment, the coats were aged at temperatures of 80 and 120 °C for the duration of 0.5 and 2 hrs, respectively. During ageing, the excess silicon precipitates from the supersaturated solid solution Al(Si) in the form of highly refined secondary crystals. Edited January 6, 2012 by AndrewG Quote Link to comment Share on other sites More sharing options...
sstein Posted January 6, 2012 Report Share Posted January 6, 2012 it is not quite as simple as that. it is not just a matter of heating it and then letting it cool. you first need a jip t stop it warping, you need to heat it to whatever temperature for a specific time and then quench it rapidly to keep the material properties what they are at the higher temperature, you then need a second treatment at a lower temperature. To be honest no matter how much you like the frame considering the time/cost/effort it would take to do it and the fact that it may not turn out right it is not really worth it. You are better off getting a new frame or if you love the frame that much trying to get hold of a second hand one Quote Link to comment Share on other sites More sharing options...
Rob Leech Posted January 7, 2012 Report Share Posted January 7, 2012 (edited) Would you be able to post a picture of the crack? Cheers, Josh. Edit- Also, that explanation above explains, in detail, why you CANNOT re-heat treat a frame successfully . Just out of interest, what are you going to use to submit the frame to these temperatures? The tolerences involved are around +-/5 degrees and considering the temperature is going to be in the region of 540 degrees, it's not an easy thing to do. Edited January 7, 2012 by Rob Leech Quote Link to comment Share on other sites More sharing options...
AndrewG Posted January 7, 2012 Author Report Share Posted January 7, 2012 Would you be able to post a picture of the crack? Cheers, Josh. Edit- Also, that explanation above explains, in detail, why you CANNOT re-heat treat a frame successfully . Just out of interest, what are you going to use to submit the frame to these temperatures? The tolerences involved are around +-/5 degrees and considering the temperature is going to be in the region of 540 degrees, it's not an easy thing to do. I really don´t know I´m need to find someone in my republic who could do this.... I will post photo later afternoon Quote Link to comment Share on other sites More sharing options...
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