To the Point: Heat Treating Aluminum Frames

Jan 22, 2013 at 0:07
Jan 22, 2013
by Richard Cunningham  
 
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Frames are hung on special racks in the heat treat oven to prevent distortion at
temperatures near 1100 degrees F. Intense photo

Jeff Steber is both the founder and creative drive behind Intense cycles. Intense is unique to most North American bike brands because it still manufactures its aluminum frames in-house at its Temecula, California, factory. All welded-aluminum frames require some sort of post heat-treatment process to return the metal back to proper hardness and consistency. Because Intense has its own heat treatment oven, we asked Jeff to take Pinkbike readers through the process.



Intense does its own heat treating in-house, which is pretty unusual for aluminum fabricators. How does this give you an advantage?

Originally, we used to use a company called Alumatherm in Orange County to source all of our heat treating, but they did not specialize in bicycle frames, so we occasionally had problems with alignment and other issues. Plus, we had to make weekly trips from Temecula to Orange County, which was a considerable distance (over 50 miles, one way). We wanted more control over the process because it was one of the most critical parts of manufacturing our frames, so I began researching the possibility of doing it ourselves. I knew that Robert Reisinger at Mountain Cycles had a heat treating oven for sale that was just about perfect for us, so when he sold the assets of his company, we bought it.


What is a heat treating oven?

Basically, it’s a big pizza oven that you put a number of frames into that are held in place with special racks. The frames are heated to a specific temperature that is close to the melting point of the aluminum alloy and held there for about an hour. A tank full of a water and glycol (antifreeze) mixture is rolled below the oven when the frames are ready. The frames are then dropped within seconds into the quench tank, which freezes the frames into an annealed state. When the frames are annealed, they are very soft and pliable – it is called ‘zero temper’ (T-0).

New frames awaiting heat treatmet

New frames waiting for the oven. The oven is elevated on the framework behind them. The quench tank is moved into place in the space below. Intense photo





TIG-welding an aluminum Tracer frame: the heat-affected zones in the weld
areas are annealed and would fail without a heat treatment. Intense photo

Why heat-treat the frames?

Actually, we are dealing with different degrees of temper within the different material we make the frame with. All of the different parts of the frame can vary from annealed condition to full temper before the frame is assembled. The tubes can arrive at the T-4 stage, which is about half strength, and the sheet that we construct the hydroformed parts is annealed at the T-0 stage. Machined parts, like the bottom bracket, dropouts and shock mounts are full hard, in the T-6 stage. Also, welding puts stresses into the frame, because the center of the welding zone is essentially annealed and very soft, while the areas around the zone can vary from soft to full hard. So, the heat-treat process is necessary to return the entire frame to a consistent level of hardness – which for us, is the T-6 temper.


Does welding and heat treating require the frames to be re-aligned?

The water/glycol mixture helps the frames cool at a consistent rate during the quenching process, which prevents warping, but there is still some misalignment in the frame that we check for while the frames are annealed. We align the frames within 12 hours while they are soft, on a special fixture, and then we put them back in the oven to artificially age them. The aluminum will automatically begin to harden at room temperature, but the oven gives us control over the final temper, which is the optimal T-6 condition.

Aligning swingarms after annealing

A batch of swingarms, just out of the annealing process, await their turn to be checked and straightened on Intense's four-inch-thick, steel alignment table. Intense photo



Explain the artificial aging process:

After the frames have been annealed, the crystalline structure of the various elements within the aluminum is more or less lined up, so when the metal is stressed, they slip over each other quite easily, which causes the metal to be easily bent or deformed. As the alloy is aged at a temperature near 350 degrees F, the crystals begin to gravitate towards each other, which forms uneven pathways for stress within the alloy. This causes the aluminum to resist deformation and it becomes much more rigid. The aging process occurs at 350 degrees for about eight hours in the oven.



A simple Rockwell hardness test is used to accurately gauge the temper of the
heat-treated frames. Intense photo


How can you be sure that the frames are annealed to the proper T-6 hardness?

We use a simple Rockwell Hardness Tester on every frame that is basically a hand-press with a pointed probe that pushes exactly the right amount into the aluminum with a measured amount of force when the temper is right. Several times a year, we send samples to an independent lab where they perform a strip-tension test that indicates the metal’s ultimate tensile strength. We also have our ovens calibrated at regular intervals to ensure consistency.

If a frame is broken, can it be repaired, welded and then re-heat treated?

Well, yeah. It depends upon whether it is repairable. Some say that it may not be
wise to re-heat-treat a frame, but we essentially are re-heat-treating each part of a frame when we first assemble them. The key to building or repairing a frame is that the aluminum cannot be contaminated with paint, grease or any foreign substance. We have a special washer that every part which will be assembled into a frame goes through and we also use it when we do a repair. The fact that 6000-series aluminum can be returned to full strength is what makes it such a good material for a frame - and makes it possible to repair them with good results.


What kinds of aluminum alloys do you use at Intense?

All of our frames are made from 6000-series aluminum. Some parts are 6061, some are related alloys like 6009, and all require the same heat treat process. We use different alloys, like 7075 for non-welded items like suspension pivots, custom screws and rocker arms that we machine which have different strength requirements, and for parts that will be anodized later.

Intense Cycles
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161 Comments

  • + 80
 "Occasionally had aligning problems"

HAHA...occasionally.
  • + 30
 Anyone who's changed the bearings on an Intense will know EXACTLY to what you're referring...
  • + 2
 Flexy uzzis, 951 Wink
  • + 2
 Same thing on the 2011/2012 M9 of my friend.
  • + 2
 totally agree
[Reply]
  • + 42
 Never fails, you build a bike overseas and people harp on your company for making low quality product. Build it in North America and people say your frames snap all the time. Pretty sure most critics can't understand the technology involved in cutting two pieces of wood the same length, just lighten up and enjoy riding.
  • + 61
 Kona may be the exception to that....build oversees, AND people say they snap all the time.
  • + 9
 Well played sir, well played.
  • + 10
 bahahaah. oh "snap" !
  • + 14
 And Commencal - see Kona.
And Giant/Spec, who are built overseas and don't snap all the time.

There is no correlation between country of origin and welding quality.
  • + 1
 Yep had that happen to a Commencal Supreme. Weld fracture where thin seat tube, fat weld and thicker top tube join. Very tricky joint to weld and get heattreated properly. Replacement frame did have a thinner weld and better matched toptube and most likely better heattreatment. No problem.

As for welding - my 951 has a very even weld seam. Very nice. The reartriangle bearings do have some bind - dont align perfectly - but then other designs - like the Commenca/Turner/Labyrinth/Scott Voltage variety keep the bearings in big blocks for easier alignment during machining and better riding.
  • - 1
 Isn't intense the company that you can hang a small car from a pole stuck through the head tube?

Every bike company has made mistakes. Some companies are better than others about getting them fixed fast. Here we just saw intense admit the problem and show us how they fixed it (getting their own oven).

Kona didn't adapt their frame building to keep up and their oversight mangled their reputation for years.
Giant had a snap issue for a while too. People don't like to hear it but it is true. Not only that, but giant denied there was a problem for most of a year, then limited access to replacement links to people after they busted theirs, meaning it might have lead to a seriously catastrophic fail that broke other parts, both bike and person.
And both of these companies could only look to their Asian slave laborers to fix it.
  • + 4
 many many frames are made alongside giant in the same factory.
  • + 1
 Right, dmadness, but with different designs from different companies.
  • + 9
 taletotell, I have to take exception to your statement "... their Asian slave laborers to fix it."

The welders at Giant are well-trained, well paid, and are extremely good welders. The jobs are prestigious, sought after, and are often handed down from father to son for all the reasons I state.
  • + 5
 more prestigious than being a moonshiner? surely you jest.
  • + 2
 Passed from father to son? How long has giant been making frames in Asia? I know they pay less for it there, since that is the point of off shoring the labor. I will grant you that it does not mean it is a bad pay for the location. Perhaps slave labor was too strong a term.
  • + 2
 Established 1972 in Dajia, Taichung County (now part of Taichung City).
Never mind. They started there, making frames for Nishiki and Schwinn. I hadn't realized they were an Asian bike company.
  • + 0
 Kidos to intense for actually keeping jobs in America!
  • + 1
 Sheeeeet, thats kudos
  • + 1
 Production has been moving out of Taiwan for several years now because they became too expensive. I love how some of us think that production of bikes in east started just recently, they've been producing quality bikes for big names before most of us were even born. Wink


Props for any company that keeps the production local!!!!!!!!
  • + 2
 I've snapped three norcos and they're made in Taiwan... but i'd say it was just a shit and poorly thought out design which caused them to snap. Or maybe the heat treating was shit... Infact i don't care, i snapped three in two years and they wouldn't warranty me or respond to my emails so they're crap.
  • + 4
 I've owned several Kona frames, from the coiler to the stinky, ranging from '05-'08 and never had anything wrong with them. No snaps, cracks, or bends. BOOM IN YA FACE!!!
  • + 0
 Every manufacturer has failures no matter where theyre made. But youll be BOOM ON YA ASS if one does snap! Lol
[Reply]
  • + 31
 For a little bit more elaboration on what Jeff was talking about with the crystal structure orientation allowing easy sliding or not, think of the following: a Rubik's cube where all the sides are lined up (normal looking). It is very easy to rotate the sides 90°, 180°, 360°.

Now take the top level and rotate it 45°, take the bottom level and rotate that 45° (both relative to the middle layer). How easily will the sides turn now? It will break first! The crystal structure of metal deforms when there is a common slip plane available. No common slip plane = rupture rather than deformation, but also means much higher strength.

Of course this is still over simplifying a whole ton of stuff involved, but still sheds a little light I hope...
  • + 10
 This is not correct. The initial heat treatment is to dissolve the alloying elements in solid solution (solution anneal). The artificial aging causes very fine and evenly distributed precipitation of solutes inside each aluminum grains structure. There is absolutely no crystal structure transformation. The shear transformation you are describing occurs when hot steel is quenched and then followed by a lower temperature thermal treatment.
  • + 36
 I don't know who to believe....
  • + 3
 If you want to know the basics of heat treating and tempering look into blacksmithing. Different metals give different results when heated and quenched. Metals like copper become harder and more brittle when worked so heating it to its critical point and quenching it makes it soft and pliable again. While high carbon steels, like the ones I work with as a knife maker, become harder and brittle after being brought to critical temperatures and quenched. Those steels then need to be tempered by heating to a specified temp and let soak for a period of time to bring the hardness back down. If you are serious about wanting some more information on heat treating check out Kevin Cashen's, a Master Bladesmith, web site. or do a google search for heat treating a specified steel. HT is not a dark magic, but it is a confusing subject. I have been making knives for 3 years now and even though I grasp the basics of HT I still send my blades out to the professionals to make sure it is done right.
  • + 12
 Jeff and I struggled to simplify the explanation of the annealing and aging process, and the one he ended up with is golden. The bottom line is that the annealing process redistributes the elements 'evenly' more or less, throughout the structure. At this point, the aluminum is called 'in solution' and at room temperature, the alloying elements then begin to move around and form an uneven 'aggregate structure' that resists shearing and thus begins to cause the metal to resist deformation and become more rigid. The artificial aging process is necessary because 6000-series aluminum will only return to a 'half-hard' T-4 condition in its natural state. Heat treating aluminum is quite a dynamic process, considering it all takes place inside a metal object that most would consider a static structure. RC
  • + 6
 Very interesting article, to add to the confusion I will add some information. As RC stated, when you finish welding a frame, you have varying hardnesses and strengths, especially in areas near welds known as the heat affected zone or HAZ. Solution annealing aims to make the complete frame into a homogeneous or consistent body - all one property of strength, dissolving hard spots (little islands or precipitates). Aging or precipitation strengthening allows precipitates to form (points in the Al that act as pinning locations for dislocation movement) in a uniform fasion to hinder the movement of dislocations (stresses). These precipitates are what makes the frame stronger because they hinder dislocation movement. It is the movement of disolcations that cause stress risers in the frame and ultimately the frame to yield (plastically deform). The reason that frames crack on welds is because you have areas of higher hardness near welds and the softer aluminum next to these hard areas is what cracks because there is a discontinuous strength i.e. dislocations moving easily through softer material until they hit a harder material and build up, eventually forming a crack. - A very tough subject to simplify
  • + 1
 Throw in the use of filler rod, which is normally a 4 or 5 series when welding 6 series, and the heat treatment/HAZ analysis gets even harder. It's not enough to say you are evening out the elements, and that once you solution heat treat and age it all becomes homogeneous, because it doesn't. The welds will have very different amounts of magnesium and silicon to the parent metal.

The most common cracks I have seen on ally frames are either weld centreline failures, where the welding process has segregated all the impurities into the last place to cool down, or, more commonly, failures on the filler-parent metal join, where the material is frequently embrittled since it is a mix of filler and parent metal, necked down because of cooling shrinkage, or has a big stress concentrator where it goes from fat weld to thin tube.
  • + 1
 True, what I meant by saying that is, more homogeneous than before. You will never get a perfect material, you can only strive to increase performance.
  • + 2
 Ok as a Materials Engineer the articles explanation sounds really confusing to me. jrhines and franky make a lot better explanation IMHO. I found a website that explains the "Heat Treatment of Aluminum-Base Alloys" pretty well:
www.asminternational.org/portal/site/www/SubjectGuideItem/?vgnextoid=5c3655c96bd9d210VgnVCM100000621e010aRCRD

Steps
1.Heating to the solution heat treating temperature and soaking long enough to put the alloy elements (i.e. not Aluminum) or compounds into solution
2.Quenching to room or some intermediate temperature (e.g., water) to keep the alloying elements or compounds in solution; essentially creating a supersaturated solid solution
3.Aging at either room temperature (natural aging) or a moderately elevated temperature (artificial aging) to cause the supersaturated solution to form a very fine precipitate in the aluminum matrix
  • + 1
 The discussion of heat treating is great. If I am not mistaken, the article seems to be confusing annealing with hardening. Taking a piece of hot metal from near melting point to a glycol/water quench sounds like a hardening process to me. Is quenching hot Al really annealing and not hardening?

I know enough to be dangerous, please correct me if wrong.

PMH
  • + 1
 It is a different process for different metals. High carbon metals are heated to its austenitization temperature, then quenched to make it hard. Yet copper get work hardened and is heated and quenched to make it soft again.

Kevin Cashen, a very knowledgeable blade smith has a lot of useful information on heat treating steel, but nothing on aluminumFrown
  • + 1
 Whoops post twice
  • + 1
 I couldn't get my old link to work. Reread my 3 steps.

1. solution treat
2. quench
3. Anneal (Age)

"2.Quenching to room or some intermediate temperature (e.g., water) to keep the alloying elements or compounds in solution; essentially creating a supersaturated solid solution"

Step 2 and step 3 are needed for a mechanism called precipitation hardening.

To my knowledge these heat treating steps are universal to both aluminum alloys and steels. Each Al alloy and steel have different recipes.
[Reply]
  • + 14
 He said "full hard".

Just sayin!
[Reply]
  • + 8
 Well... all this Intense HQ tour here in Pinkbike is reminding me that after riding my good old M1 and Uzzi sl for half a decade without issues my M9 is a pain since day one. It rides amazingly but, the noises and the frequently play of this first M9 makes my regret not taking other brand route. They never stood with me as a customer when my first complaints arrived early by email, suggesting me to buy the new linkage system. Recently I've made a dent on the swing arm (here the thinner lighter FRO alu has it's disadvantages on rocks) and I'm still waiting for a Customer Service reply regarding a price for a new one. It's hard to realize that my money went to a product that took all this effort and meticulous production process, and in the end of the day this does not apply in customer care.
  • + 5
 thats poor business on their part
  • + 5
 I found their customer care to be beyond bad. I would never consider buying another Intense, (no matter how beautiful they are to look at!)
  • + 2
 well if its any consolation i was considering an m-9 to replace my v-10 next year... with these reviews i think i may avoid it...
  • + 3
 I've found their customer service good, on two Tracers I've owned. Intense has taken care of me on both occasions. That being said, both frames have had alignment issues - one required a rear triangle replacement and the other required repair through different width shims. Thanks for the article. Great read.
  • + 2
 I'm shure there is plenty of good experiences...
  • + 1
 customer service is my hot button. I want to know that the company will have my back if the strangest weirdest i never saw that before thing happens. Santa Cruz has been decent but I havent had any issues...
  • + 2
 I live in whistler. During the 2012 bike park season I had 3 friends who rode intense bikes(2 m9's and 1 951). All 3 managed to crack either the front triangle or rear triangle, taking several months to get warranties. I wouldn't suggest intense as a park bike.
[Reply]
  • + 10
 It's good to hear some bike companies are not sending work to China or Taiwan.
  • + 1
 Intense doesn't send the alloy work to china, the carbon frames however they do get produced in asia. You'd have to ask them for the name of the manufacturer they use, google can then tell you where their factories are.
  • + 1
 Intense gets many of their tubes fluidformed by giant in taiwan. As do most companies.
  • + 3
 @ Deeeight, Intense has their carbon manufacturing work done in Germany actually. by a company named SEED. they are trying hard to bring carbon production to the US
  • + 1
 I thought I read that SEED did the engineering , R & D for intence carbon bikes and the actual manufacturing was Asia
  • + 1
 that could be a possibility as well. the sales rep mentioned SEED was engineering and producing the first carbines. I`m not sure where there manufacturing facilities for such are located. Typically with a specialized design process you also have specialized manufacturing process that are for the most part in house or a local partnered business to ensure repeat ability and the proper application of your design process. quality control can only validate so many of the manufacturing process`s performed from an external manufacturer.
[Reply]
  • + 11
 Now that's a beautiful raw finish.
[Reply]
  • + 2
 I do love the look and ride of an Intense bike, My 951 did not put a foot wrong in the almost 2 years I owned it, but they do dent by literally just looking at it, and the many pics I've seen of a snapped 951 has not put my mind to rest, you always thinking........... "Are you going to snap on me?" Never had to deal with Intense as a company but also only heard bad things about there customer service. And its an absolute bitch to change the bearings, took me about 6 hours to remove and install new bearings. I do wish Intense a good future but its hard to compete against other bike companies like Nukeproof, YT Industries and many more who offer a frame at sometimes half the price and that have very good reviews and customer service is ace.
[Reply]
  • + 2
 Really interesting article, valuable information. As someone who welds aluminum on a regular basis, I've often wondered what processes a mountainbike frame would go through. Well, now I do. Thanks RC!
[Reply]
  • + 1
 Really surprised to hear they only use 6000 series Aluminum for the frame.7000 series aluminum is supposed to be much stronger and withstand flex related cracking by up to 10X.At least their pivot and rocker plates are 7000 series.Banshee takes it a step further and uses 7000 series for everything plus stock ti pivot axles.Canadian company,built in Taiwan by Canadian guys.
www.vitalmtb.com/photos/features/The-Making-of-a-Frame-with-Banshee-Bikes,4763/Slideshow,0/bturman,109
  • + 1
 Strangely enough, I own a 2003 Brodie Demon and a 2008 Brodie Devo. Both frames are constructed from 7005 series aluminum. I know Brodies arent an overly sought after DH bike, but they are definitely long lasting and tough frames
  • + 1
 I was always under the perception that 7005 was stiffer, but more likely to be brittle. I think I remember reading that from the old BikePro catalog I have somewhere, there was a full page on different types of aluminum.
[Reply]
  • + 3
 On my 7 th intense frame now, not broke any of them...all have been raced ans a couple of them are second hand ! That includes M1's which were already 10 years old.
[Reply]
  • + 1
 7000 series aluminum is very strong compared to 6000 series aluminum.
So why 6000 series Al.?
The welds are the weak point. When you heat treat after welding the entire frame has the same strenghth. Heat treating causes the grains to alighn and connect in a tighter matrix.
That said there is no perfect material. It all boils down to engineering and fabrication.
  • + 1
 I have one frame out of 7046, which is presumably much stronger than 7005. Did not break it so far.
[Reply]
  • + 1
 if you want something done properly you have to do it yourself... here is the proof lol they make their own frames... love it... 6061 aluminium thats the type of aluminium of the old specialized its great i have a haro x7 its 6061 its so thin looks weak but its strong...
[Reply]
  • + 1
 My M9 was rock solid. Any noises were solved just by adding a little grease, which you should do anyway. The slopestyle is still going strong and the warranty on my tracer was dealt with very quickly. Love 'em.
[Reply]
  • + 3
 It is so rad to still have the best/ stylish bikes made in North America. Keep it up Jeff!!

I love my M9!!
[Reply]
  • + 2
 Every engineer out there is trying to flex his nuts about this. It's a very well put together general explanation of the process. I just wish I could work there!
[Reply]
  • + 0
 Owning both, think the weld quality is much better on Giant than it is on Intense, and I don't care if my frame was made in Taiwan as long as they did the job right I could care less. But what I like the most is paying 1000 dollars less for a frame set.
  • + 7
 Wait, you COULD care less? so you do care quite a bit then? Americans always seem to struggle with that phrase, but, to be fair, I couldn't care less Razz
[Reply]
  • + 3
 This is the answer for the stupid people that thinks weld a broken frame will resolve it all....
  • + 2
 Hey dude ive welded and repaired many frames with very good results It can be done
  • + 1
 I know it can be done.... but all the heating tratment its wasted when you "fix" a frame re-welding it. A fissure its never going to happend in the welded zone but for sure its going to be in the side of the welding.
  • + 1
 "TIG-welding an aluminum Tracer frame: the heat-affected zones in the weld
areas are annealed and would fail without a heat treatment."
  • + 1
 The heat treatment is only affected in the area that is welded, it's a better option to weld a cracked frame than run it cracked. Although sometimes it's not worth welding if it's serious such as a head tube crack or if the bike is developing a lot of cracks in multiple places.
  • + 1
 The problem I faced was my $400 Iron Horse MKIII frame cost $75 to have a gusset plate welded onto the crack in the rear triangle, but another $300 for the heat treatment since it was a bespoke custom job, and didn't matter if it was 1 bike or 6 in the oven. Not worth it, and the weld lasted a while without heat treatment, but failed on my first decent crash. Found a smaller crack under the top tube so gave up and bought a new bike. No point throwing good money after bad.
  • + 1
 The both are right.. oviously is better to ride a welded frame that was craked... By the other hand isnt clever to pay a $300 heat treatment in a $400 dollar frame.... What I say is that most of the people, when somebody ask for the best option for a craked frame, they answer things like: " - Bro, i know a "NASA" welder that can fix it ", "-Dont worry the frame will be more stronger", "-I've welded my frame 3 times and nothings wrong with it".... haha the last one its true and its totally stupid...... So, if you have a $200 - $400 frame you can fix it welding it until you have the money for a new frame, isnt safe, but we are not going to stop riding. Ride in a welded frame isnt safe, the best welder can "fix" a crak, but internally the frame have lost their propertys to be strong in a ride. A big jump, drop off, brake, or even just a high speed ride can broke it....

P.D.: Sorry for my english Frown
  • + 1
 It is still safe to ride a frame that has had a small amount of welding after heat treatment. Cracks don't happen in crashes, maybe that's when you first noticed the crack was coming back. I am a welder myself and ride an orange patriot which had a crack appear 3 seasons ago and it's been welded, I've ridden Fort bill and a lot of other tracks considered to be harsh it's still going good. It'll never be stronger but if you do it right it'll hold up for a while.
  • + 1
 Im not agree with your first part.... When I was child I used to do BMX... my father dont give a f*ck when I crak the frame... I think in a year my frame was welded 4 times... and it craked again at the side of the previous welded zone.... It never brokes in a half... but ther's the posibility... and no one wants to try it....

My conclution: welding a frame affects a lot the internal crystalline structure of the metal, and heat treatment helps it to order it and make and stronger-flexible frame.... Weld a frame it is not safe, but if you dont have the money it will help you to safe some bucks to buy a new frame and continue riding....
  • + 1
 No offence but I have a feeling you're just regurgitating what you have read, yes heat treatment is used to do a wide range of things, from hardening to normalizing the structure of the metal. Heat has different effects on metals, high carbon steels can become brittle after welding and aluminium ( the alloys I'm working with) become more malleable. As spannersandhammers already said it is possible for a frame in the right hands to be repaired and last a considerable amount of time.
  • + 2
 @EuanBisset "Cracks don't happen in crashes,"

Sorry, but the crack happened because of the crash. I was already aware that not heat treating the weld was a risk, so inspected the weld after every ride. The crash ruined the rear rim as well so I had to walk the bike out.

It was a quality weld, but on a problem area (poor design), as lots of other MKIII frames crack in the same place:
dl.dropbox.com/u/8190002/Gusset.jpg

I kept riding the bike for a few months after the crack appeared, mainly because I thought even if it goes completely the rear triangle would still hang together (which it did, yay gaffa!). Gave up once it went all the way around:
dl.dropbox.com/u/8190002/IHCrack.jpg
  • + 1
 Thats what Im talking about.... its wrong to think a nice welded crak its going to be stronger enought....
[Reply]
  • + 1
 This is what I was saying on another article when someone said aluminum frames where repairable and carbon was not. Carbon is way more repairable! No heat treat process is required afterward.
  • + 6
 And seeing just how involved it can get to produce aluminum frames, I wonder why carbon frames cost so much.
  • + 3
 Carbon is not reparable, it is patch-able. But once the fiber is broken or cut just glueing it will not make it one piece again. A carbon frame need way more manutention and manual process, AND way more expensive frame mold and cure in an oven too.
  • + 4
 Really? I'm an aircraft mechanic that's "repaired" many carbon aircraft components per engineering requirements. Parts that go thru way more stress than a bike will ever see. And carbon components can cure without an oven, they just cure faster with one.
  • + 0
 i must assume that carbon components in an airplane aren't structural components therefore they can be ''patched'' only ???
  • + 3
 richwantsout is correct. carbon fiber is essentially like wood - strong fibers, bound together in a resin matrix - and a structural carbon part can be repaired in similar fashion. The 'patch' must be united with enough of the underlying fibers to transfer the loads and often, tapered gradually over a substantial area to eliminate stress risers. Carbon road bikes are routinely repaired these days, so there is no magic in assuming that carbon mountain bike frame could be fixed as well.
  • + 1
 If anyone is a doubter of carbon fiber just read about the new Boeing dream liner. It's having a lot of mechanical problems right now, but not structural problems. It's made from 80% composite materials.
www.jyi.org/issue/the-boeing-787-dreamliner-designing-an-aircraft-for-the-future
  • + 7
 Only on Pinkbike can a guy who repairs composite components on aircraft get negged propped because he 'is wrong' about whether or not carbon can be repaired.
  • + 0
 Carbon in airframes is an altogether different beast than visual-bike-carbon.

Fixing aluminiumframes - not likely - they would have to look entirely different designwise, bolted/riveted/glued exchangeable sections. Imagine a 1950 Cessna.

Long life frames best made out of steel or titanium.
Nice choice of tubes:
en.wikipedia.org/wiki/Reynolds_Cycle_Technology
  • + 1
 Article from Bicycling Magazine indicating carbon can be repaired.

"A properly restored frame will also be just as strong as its unbroken original. One composite engineer at a major bike brand who spoke on the condition of anonymity said he has performed pedal and head-tube fatigue tests on repaired carbon frames and found they passed his company's internal standards. It's even possible a cracked frame can come back stronger if it was damaged in an underengineered area or failed due to a manufacturing defect."

www.bicycling.com/maintenance/repair-maintenance/resurrection-calfees-carbon-frame-repair
  • + 1
 Thank you sir!!!!
[Reply]
  • + 2
 Aluminum cannot be designed for "infinite life" like steel or titanium. Plus for the same reasons, it is very sensitive to weld quality, fillers, and impulse loads.
[Reply]
  • + 2
 this post was really ascinating I love all these post about how they made my bike awesome!!!
[Reply]
  • + 1
 So, they are not good enough to make it straight and aligned out of 7005 or 7020? Smile Taiwanese welders can.

Or is it because they need to hydroform a lot?
[Reply]
  • + 2
 good idea of interview.. i enjoyed it. it's feel nice when the study zone interference with your hobby
[Reply]
  • + 1
 Would heating it back up, like getting it powder coated, have any affects on th frame?
  • + 2
 powder coating only goes to 390F for 10 minutes, so no. if it did, manufacturers would not use powder coating to color their frames.
  • + 1
 thanks i didnt think it would make a difference but i have heard people say it would and that it would void the warrantey cuz of it. Im hoping to get my frame powder coated so i was just double checking
  • + 2
 novajustin is right, but if you are under warranty you may want to double check that it will not void the warranty. Warranties can be full of small print and may have loopholes that make no sense - depending on the company. I had the same concerns with powder coating an aluminium frame, but was assured the heating would do no damage. That frame was way past warranty at that point though. The powder coat still looks great almost 4 years later, way better than the factory paint.
  • + 0
 No brand/manufacturer would touch a warranty claim on a frame with a non-standard (eg powdercoated) finish.
  • + 1
 Brit-500 - Turner happily warrantied my powdercoated frame recently. Excellent customer service..
  • + 1
 It's probably not hot enough, but I want to know. Where is Cunningham?
  • + 1
 Typically, powder coating heats the frame between 250 and 350 F. for ten to 30 minutes - not enough to barbecue your frame and weaken the metal. Many bike makers powdercoat exclusively, so it is an accepted practice. In many environmentally active cities, however, powder coat houses avoid expensive chemicals and permits with ovens - they remove the old paint by heating the frames to about 1000 degrees, which turns the previous paint to ash and will murder your expensive aluminum chassis. It would be prudent to know exactly what will happen to your bike when you send it out for a new paint job.
  • + 1
 Although it is possible to powder coat and not get overaging, it is also possible to get overaging with powder coating alone (without heatiing the frames to anywhere near 1000 degrees to clean the frame) Overaging results in a weaker frame.

digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=1009&context=mech_fac (Nobble's link in a pinkbike thread)
Scroll to conclusion.

The bike manufacturers will get it right. Getting a bad reputation, and having to contend with warranty returns are great motivating reasons.. Even if they didn't get it right at the beginning, they will find out soon enough from examining return frames when looking for cause of failure. They can tweak the process until they get it right. However, for the average owner wanting to get powder coating done, that is entirely another story.
[Reply]
  • + 1
 That's how the dmr 898 got it's name,
heat treated to 898°c I believe correct me if I'm wrong.
  • - 3
 scholars maintain it is heated to 890, dmr are just fucking with your head
  • + 1
 haha joke chill, what 'scholars' do you know that even know what a dmr is?
  • + 1
 Haha probably none.
[Reply]
  • + 1
 Anyone want to buy my M6?
  • + 6
 Has it ever been left in direct sun light or next to a hot radiator ?
  • + 2
 No and no...just can't seem to re-sell. It's got good reviews. But not by me, i hate it.
  • + 1
 or near your gf when she's been drying her hair ?
  • + 1
 i had to let my red m6 go complete for 1700..
  • + 1
 They break like twigs and you cannot find replacement parts!
  • + 0
 I can agree some of their links break, but I've never had a problem with an intense triangle, but even if you break something, link or frame they will make it right. I've walked in with my broken links and walked out with brand new ones free.I've seen a guy walk in with a way out dated frame with a broken rear triangle that they didn't have a replacement for so they gave him the new ss frame for free no questions asked
[Reply]
  • - 2
 Fro is just a marketing term it's no different to the stock bikes. Feel the weight of an m9 frame. It's solid. As for all the snapping frams I think Trek and recently Devinci would top intense any time.
  • + 3
 fro is referring to the geo I believe
  • + 1
 FRO, For Racing Only
[Reply]
  • + 1
 Anybody know the process for aligning a frame? Never heard of that before.
  • + 7
 If you check out the Orange factory video (I think its called It Is What It Is, probably on youtube) they have a guy in the basement who sees each frame 3-4 times throughout the build process. He has a movable jig that he can put any of their frames into and then has sliding gauges that he checks the frame with. If its off he literally uses a breaker bar or a hammer to tweak it back into place. Not sure how Intense does it but I don't think there is any other way but brute force and blunt objects.
  • + 5
 www.youtube.com/watch?v=mlIYEdRFQu4 - its hard to understand Guy Martin, but remember that he can ride a superbike around the Isle of Mann faster than almost anyone on the planet, so cut him some slack. The alignment starts about halfway in.
  • + 2
 I have seen it on my trail honda....Simple process: two big guys with hammers! Big Grin
  • + 1
 you sure guy martin weren't doping too ? haha lol

i love a good ol engineering read or video espesh a bike one
  • + 3
 Nicolai video has it as well. Essentially, you're just man handling (for lack of a better term) the frame to bend past the point of elasticity to hold it's shape. then it's checked with tooling/fixturing/gauges and clamped into a frame for final heat treat to T6. At least that's how it's supposed to be done. Annealing is fine without a fixture (actually how I reccomend doing it), and final hardening to T6 should be done in a fixture/jig. Since bike frames are somewhat symetrical, they are easier than some of the more complicated aluminum structures that require the process. Like a HELRAS frame for instance.
  • + 3
 Elastic deformation is when something stresses/bends and returns back to the point it was at before. Plastic deformation is when you bend it to a new point and it doesn't return. A good example of the two differences can be seen easily how crank arms are installed on any BB spindle with a tapered fit (either onto a square or splined interface). The crank arms are generally made of the softer/weaker material, and the interface is elastically deforming under pressure against the harder/stronger material of the BB spindle. Done to the proper stress level, you can install and remove crank arms dozens of times without any ill effects to them that you'd ever detect while riding. Use too much pressure though and you'll see plastic deformation as the crank arm installs incorrectly and when you remove them again, they won't fit properly during the next installation cycle if you try and use the correct amount of pressure again. This is why every crank arm installation manual lists a torque value to use on the bolts that are responsible for the application of pressure to the arms, and to get that torque achieved correctly you need to use a torque wrench AND properly lubricate the surfaces being joined together.

Few bicycle mechanics EVER use a torque wrench though and I know of many shops that don't even own one, let alone home mechanics.... but with cars and motorcycles and especially aircraft mechanics... everyone owns their torque wrenches and they use them all religiously. But for some reason, bicyclists don't think the laws of metallurgy and physics apply to them.
  • + 1
 I use my torque wrench all the time, I love not having to worry about it. Manufacturer lists torque spec/I set bolt to torque spec/No longer my problem.
[Reply]
  • + 1
 Finally! Sick. Now they just need to offer a better warranty!
  • - 1
 Why warranty? They offer life time warranty for all of the frames. Thats mean front tringle of course!
  • + 2
 lifetime? all i know that 2 years then you're on you'r own :/
  • + 4
 Intense have a bad rep with regards to warranty, if you read the terms of their warranty it's void as soon as you swing a leg over it.

"The warranty will not cover normal wear and tear, normal maintenance items, damage, failure, accidents, crashing, abuse, mis-use, neglect, or any damage caused by bicycle components.
Intense frames are not intended for use in stunt riding, ramp riding, hucking or any similar activity."
  • + 2
 The key word is "failure." They hung me out to dry when my top link broke. Wouldn't even sell me one for cheap. It broke due to fatigue from a under built part!
[Reply]
  • + 0
 Wow...i just enjoy riding my bike, i don't need to know how it's made
[Reply]
  • + 1
 Now that's magic...
[Reply]
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