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 Post subject: ti
PostPosted: November 6, 2007, 11:19 pm 
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Joined: December 2, 2006, 7:17 am
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Bikeschool does TI welding classes for bike frames. It can be welded in the open with a type of extended cup over the tig.iirc their 1" round tubing is about $30 a foot. 10x the price of 4130 for a 50% weight reduction? That could buy alot of cnc time for custom hubs /forged wheels/ Maybe TI sprint car rotors. I think that type of stuff would have more effect on handling than anything.

Although I bought 600 surplus TI screws that I'm using on my next car,purely for the sex factor.

Have you gotten a quote from those folks?


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PostPosted: November 18, 2007, 10:51 pm 
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Location: Coral Gables, Florida
Generally, we have to keep in mind that most performance chassis are optimized for stiffness rather than strength. If you design a suitably stiff chassis, it will have a huge strength safety factor.

All other things being equal, stiffness is a linear function of Young's modulus (called "E"). The E value of Aluminum is 10 million (no units), E for titanium is 20 million and E for steel is 30 million. NOW HERE'S THE INTERESTING BIT: Titanium weighs twice as much as aluminum and steel weighs three times as much as aluminum. Their E values are in exactly the same ratios as their weight!!!

So what's the bottom line? In a properly designed chassis, the weight for a specific stiffness will WEIGH THE SAME NO MATTER WHAT THE METAL USED. That is why most spaceframe chassis, like the Super 7, were made from carbon steels, not chrome/moly, titanium or aluminum.

Airplanes on the other hand a mostly concerned with weight, not stiffness, so it makes sence for them to use exotic and expensive alloys.

Bill Box


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PostPosted: November 18, 2007, 11:17 pm 
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bbox wrote:
Airplanes on the other hand a mostly concerned with weight, not stiffness, so it makes sence for them to use exotic and expensive alloys.
Bill Box


Aircraft also have far lower torque requirements end-to-end, and by using a huge tube (the fuselage) it give incredibly high stiffness in torsion, whether wanted or not.

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PostPosted: November 19, 2007, 12:58 am 
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violentblue wrote:
ever seen thermite in action, aluminum powder mixed with equal parts rust. once it starts burning, it will not stop untill its all used up, it will burn right through a iron engine block.
I saw thermite in action once, at the CMC factory. It's something to think about if you use the same plasma cutting table for aluminum and steel. They say cleanliness is next to godliness, but a lack thereof could also give you fast track access to your maker.

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PostPosted: November 19, 2007, 9:46 am 
JackMcCornack wrote:
violentblue wrote:
ever seen thermite in action, aluminum powder mixed with equal parts rust. once it starts burning, it will not stop untill its all used up, it will burn right through a iron engine block.
I saw thermite in action once, at the CMC factory. It's something to think about if you use the same plasma cutting table for aluminum and steel. They say cleanliness is next to godliness, but a lack thereof could also give you fast track access to your maker.


I saw a video of a thermite flare used for countering anti-air missiles. It was burning as it hit the ocean. Then you could clearly see it burning as it sank. So, literally the entire ocean couldn't put out that flare...


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PostPosted: November 19, 2007, 10:14 am 
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Joined: April 23, 2006, 8:26 pm
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JackMcCornack wrote:
violentblue wrote:
ever seen thermite in action, aluminum powder mixed with equal parts rust. once it starts burning, it will not stop untill its all used up, it will burn right through a iron engine block.
I saw thermite in action once, at the CMC factory. It's something to think about if you use the same plasma cutting table for aluminum and steel. They say cleanliness is next to godliness, but a lack thereof could also give you fast track access to your maker.


It doesn't explode, it just burns hot. Unless you light a pot of it on top of a gas tank, or on top of your welding tanks, your maker wouldn't need to be notified.

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PostPosted: November 19, 2007, 1:24 pm 
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This could be a first! We have the makings of a literal 'flame war'.

True, thermite doesn't explode. Its main danger is it sets other stuff on fire. You'd have to have a pretty dang unhygienic workshop for a thermite fire to be genuinely dangerous, and if it remains confined to the plasma cutting table, you can just wait it out. However, if precision is one of your priorities, it's an area that can use a shopvac now and then because--even though it's not actually dangerous--a thermite fire in the structure of manufacturing equipment may throw it out of alignment.

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PostPosted: November 20, 2007, 12:11 pm 
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Uhh...one of the problems of keyboard communication is the lack of inflection, making it hard to tell deadpan humor from serious belief. So in case I missed the mark, let me clearly state: I was kidding about the flame war.

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 Post subject: Re: Titanium frame?
PostPosted: June 12, 2010, 2:18 pm 
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One of the things that surprised me about a locost chassis is the small size of the tubes and the thin (.09") wall thickness used. If you reengineered the chassis to take advantage of the strength to use thinner tubing, you might end up with something so thin it would be too difficult to weld without burning through.
Oh, and all those lovely sparks you see from IRL cars with a full fuel load in the corners? That's from titanium rubbing blocks.


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 Post subject: Re: Titanium frame?
PostPosted: June 18, 2010, 8:29 pm 
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Joined: June 17, 2010, 7:03 pm
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jerelw wrote:
One of the things that surprised me about a locost chassis is the small size of the tubes and the thin (.09") wall thickness used. If you reengineered the chassis to take advantage of the strength to use thinner tubing, you might end up with something so thin it would be too difficult to weld without burning through.
Oh, and all those lovely sparks you see from IRL cars with a full fuel load in the corners? That's from titanium rubbing blocks.



i've always wondered where the mini-truckin community got the idea....

there isn't really anything like dragging down the highway at 70 with a 300 foot trail of white-hot sparks following you.


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 Post subject: Re:
PostPosted: July 11, 2010, 10:26 pm 
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bbox wrote:
. That is why most spaceframe chassis, like the Super 7, were made from carbon steels, not chrome/moly, titanium or Aluminium.



In the real world it's the cheapest and easiest material to work. Thats also why the majority of us use it. I recently saw the Boss of Ford say "the day you can show me a cheaper, more pliable material than steel we will be there".

I believe motorcycles that look for extreme weight losses use aluminium where they can in mass production to cover production variations - a 0.005" variation on 0.040" steel is 12% but only 6% on 0.080" aluminium maintaining a higher safety margin and QC.


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 Post subject: Re: Titanium frame?
PostPosted: September 23, 2011, 1:41 am 
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Maybe a combination then?

Titanium bulkhead/subframes, connected by steel tubes, wrapped in a structural carbon fiber skin.


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 Post subject: Re:
PostPosted: September 28, 2011, 4:51 am 
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jmanz6 wrote:

How about the Magnesium engine blocks that BMW is working on? No iron sleeve, ALL Magnesium. It's cool as all get out!! AND it doesn't catch fire.


???

VW Beetles had their blocks made from mag before you and I were born and anyone who's worked on 60's Honda motorcycles will remember "magnesium" cast onto their casings.

I heard this year BMW has announced a new composite magnesium/aluminum where the magnesium is cast around the aluminium liners and that's never been done before in production.


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 Post subject: Re: Titanium frame?
PostPosted: September 28, 2011, 8:28 am 
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I used to teach fire safety in the FD. We did a demonstration using flour dust which caused a pretty good explosion but we also did it with steel powder, aluminum powder and earth powder, (dirt).

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 Post subject: Re: Titanium frame?
PostPosted: September 28, 2011, 10:03 am 
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I seem to recall when I was racing Mini Se7ens that there were a number of people getting T45 roll cages, but then they got banned due to safety issues. Turns out they were not being installed correctly and the welds were breaking. Now someone further up said they don't need annealing/heat treating so i'm curious as to what was going on there then.

Also, I saw a Ti wingbox from some fighter plane in the Deutsches Museum. It was an amasing article, just to look at and touch. I hovered round if every time I went there lol. Lovely museum btw :) I was there all the time when I lived there.

Tom...


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