# Lower grade titanium coming on the market?



## Haz (Oct 21, 2009)

There appears to be a flood of Titanium lights coming onto the market, at much lower prices than we are accustom to in the past. Questions are starting to be raised about the quality of these material, given that titanium lights are being sold at prices we normally only see on aluminium lights.

Speculations about China making titanium alloys with less titanium has arisen due to released specifications of certain lights appear 'heavier' than one would expect given the material that is being used.

Some fear the quality is not the same, given that the alloy may not be as pure compared to some more expensive lights being sold.

Are these concerns people are having about the strength, rust resistant, weight valid?, or not significant enough to warrant any concern?

I don't know much about Titanium, but i would think Ti alloy will have to have a minimum volume of Titanium in them to be allowed to be called Titanium. Is there any point at which the name can no longer be used?


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## Milling_And_Grinding (Oct 21, 2009)

I don't believe there are any set "values" for what the composition of a Titanium alloy would be. I sure hope there isn't an influx of some sort of lower grade titanium being used in something that demands a very high quality composition of titanium be used, but I think concern over its strength, etc. for use in flashlights isn't very warranted. 

I know wikipedia isn't the best source, but just for reference:

http://en.wikipedia.org/wiki/Titanium_alloy


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## Marduke (Oct 21, 2009)

An alloy is named by the highest percentage constituent component.


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## RocketTomato (Oct 21, 2009)

Actually one of the higher quality commonly used grades, Ti 6Al-4V, is only 90% Titanium. The handy naming system tell us that the remaining 10% consists of 6% Aluminum and 4% Vanadium. It also has a slightly lower density then pure Ti so a light made of pure Ti light would be heavier.

A company producing Ti lights (even in a limited quantity of say 500) can do it much cheaper then a custom light maker can.


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## Sgt. LED (Oct 22, 2009)

As long as it doesn't rust, is lighter than steel, and is about as strong as steel (or at least tougher than aluminum) then bring on the cheap stuff!

Why not, I mean as long as it's disclosed to us and reflected in the price. :thumbsup:


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## compasillo (Oct 22, 2009)

Haz said:


> There appears to be a flood of Titanium lights coming onto the market, at much lower prices than we are accustom to in the past. Questions are starting to be raised about the quality of these material, given that titanium lights are being sold at prices we normally only see on aluminium lights.
> 
> Speculations about China making titanium alloys with less titanium has arisen due to released specifications of certain lights appear 'heavier' than one would expect given the material that is being used.
> 
> ...




I started this question at the Battery Junction threads announcing their new Titanium Innovations IlluminaTi AAA flashlight and Ti Olight AAA (ITP). There was something wrong about the weight of the flashlights that called my attention so I was asking for some clarifying info. That's all.
All I wanted to know is "what do am I purchasing?"... a very simple question since we all are consumers and like to read every product tag about composition, ingredients, etc. So, are flashlights out of this consumer behaviour/rules? I honestly think it should not.

I don't want to bring anybody's expectations down but info doesn't ever hurt, IMO


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## compasillo (Oct 22, 2009)

Sgt. LED said:


> As long as it doesn't rust, *is lighter than steel*, and is about as strong as steel (or at least tougher than aluminum) then bring on the cheap stuff!
> 
> Why not, I mean as long as it's disclosed to us and reflected in the price. :thumbsup:



I agree with you. Improvements are always welcome, concerning prices and features. The thing is that these flashlights are heavier (and more expensive) than SS ???, at least that's the data from the dealer. Typo? mysterious alloy?


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## compasillo (Oct 22, 2009)

RocketTomato said:


> Actually one of the higher quality commonly used grades, Ti 6Al-4V, is only 90% Titanium. The handy naming system tell us that the remaining 10% consists of 6% Aluminum and 4% Vanadium. It also has a slightly lower density then pure Ti so a light made of pure Ti light would be heavier.




_Only_ 90% Ti is what a standard alloy has. Ti6Al4V is included in the group named Grade 5, commonly used in surgery, piercing, glasses, and an infinity of items denominated under a "titanium made of" tag. A pure commercial Titanium alloy has a 99% Ti (Grade 2) and it's for heavy duty stuff (higher price). I don't expect a pure Titanium alloy in these flashlights. 
Regarding the slight difference in density between a pure and a standard alloy it would be as small as it never would explain such a big difference in weight and even much less in price.

Whatever it was the alloy, I'll end purchasing it if I like the flashlight. that's for sure


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## Rothrandir (Oct 22, 2009)

The way I see it, it's kind of a complicated issue in flashlights.

The majority of people buying titanium flashlights do so because of it's perceived uniqueness or coolness. Titanium can be considered "overkill" for a flashlight in most (but not all) applications. In fact some might argue that titanium is an inferior material for some flashlight applications.

That being the case, it is ultimately up to the buyer to determine if cheaper titanium is beneficial or detrimental. I would personally be of the opinion that under any circumstance a cheaper material is inferior, because if A: you need the unique properties of titanium in your light, a cheaper alloy will not perform as well, or even B: you bought a titanium light simply because it's titanium, you're not getting the premium product that you're after...

Personally, whenever I make something I always use the best quality *domestically produced* materials I can get, even if that means ordering from more expensive vendors to get the better stuff. On items like the keychain pens I make, they are made out of 6AL4V titanium and 316 stainless. Do the products demand these better, more expensive and harder to work with materials to function? No, I just believe in doing things right.


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## compasillo (Oct 23, 2009)

I agree with you Rothrandir. As far as it may concerns to me I'm not a fan of Ti in flashlights, at least not yet. 
I think this thread started regarding the other thread's discussion on the possibility that an announced Ti flashlight was not high grade Ti made of... (based on the data given by the dealer). 
Once the dealer has clarified the things, speculations make no more sense.


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## easilyled (Oct 23, 2009)

The dealer has clarified that the light is made of grade 2 (or commercially pure) Titanium in the thread in question.


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## octaf (Oct 23, 2009)

Generally speaking, you get what you paid for, but not always.

I've done some little things with Ti's and I dealt with US made, Japan made and China made Grade 2 Ti's & Grade 5 Ti's, so far.

Actually there is not much difference in price, and it's not easy for consumers to distinguish the difference in quality, although US & Japan made Ti's considered to be superior to China made Ti's up to now.

Here's what I heard from the dealers; Within a couple of years, the majority of Ti materials in the market will be replaced by China made Ti's, and actually the gap in quality difference is getting thinner.


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## easilyled (Oct 23, 2009)

octaf said:


> Generally speaking, you get what you paid for, but not always.
> 
> I've done some little things with Ti's and I dealt with US made, Japan made and China made Grade 2 Ti's & Grade 5 Ti's, so far.
> 
> ...



octaf, you seem to be an expert in this field, so I'd be very interested to know in what way Chinese produced Titanium stock is not of the same quality as that from the US.

Does it have impurities in it and does this affect the ability to produce a nice finish?


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## fyrstormer (Oct 23, 2009)

Sgt. LED said:


> As long as it doesn't rust, is lighter than steel, and is about as strong as steel (or at least tougher than aluminum) then bring on the cheap stuff!
> 
> Why not, I mean as long as it's disclosed to us and reflected in the price. :thumbsup:


Titanium alloys with more aluminum and vanadium would actually be ideal for flashlights, because both aluminum and vanadium have substantially better electrical and thermal conductivity than titanium has. In addition, the Mohs hardness (scratch test) of vanadium is almost as high as titanium; I couldn't find a Vickers hardness (impact test) for vanadium, but from the crystalline structure it looks pretty damn hard.

I mean, it's certainly nice to know my McGizmos could be run over by a dump truck with no ill effects, but let's be honest -- that is almost certainly never going to happen, and if a softer, lighter, more-conductive alloy that doesn't sacrifice too much strength is available, then why not use it?


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## KuKu427 (Oct 23, 2009)

Correct me if I am wrong. CP Ti is much easier to machine than 6/4 Ti right? I guess that could account for a lot of the difference in prices. Some machine shops are willing to do CP Ti parts, but not many would venture into 6/4 Ti.


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## octaf (Oct 23, 2009)

easilyled said:


> octaf, you seem to be an expert in this field, so I'd be very interested to know in what way Chinese produced Titanium stock is not of the same quality as that from the US.
> 
> Does it have impurities in it and does this affect the ability to produce a nice finish?


 
Hi, easilyled.

No, I'm not an expert on this.
I haven't done the scientific tests myself, either.
I'm talking about the general perception that consumers have in their mind.


I have dealt with 6-4 Ti's from different country and manufacturers.
I've done some tests with Rockwell C scale. Their general ranges are 32 ~ 35. In general, pricy ones tends to be in higher numbers in that scale. And I often heard machinists saying that they feel the difference when they machine the 6-4 Ti's from different sources.


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## octaf (Oct 23, 2009)

KuKu427 said:


> Correct me if I am wrong. CP Ti is much easier to machine than 6/4 Ti right? I guess that could account for a lot of the difference in prices. Some machine shops are willing to do CP Ti parts, but not many would venture into 6/4 Ti.


 
You're definitely right, Ku !

6-4 Ti's are much harder to machine than CP Ti's. Big difference.


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## Marduke (Oct 24, 2009)

octaf said:


> Hi, easilyled.
> 
> No, I'm not an expert on this.
> I haven't done the scientific tests myself, either.
> ...



Composition does not take heat treatment into account, which can make a HUGE difference.


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## octaf (Oct 24, 2009)

Marduke said:


> Composition does not take heat treatment into account, which can make a HUGE difference.


 
Please, be more specific about this.
I was talking about the bare 6-4 Ti's, not the heat treated ones. :thinking:


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## Marduke (Oct 24, 2009)

octaf said:


> Please, be more specific about this.
> I was talking about the bare 6-4 Ti's, not the heat treated ones. :thinking:



Just saying "Ti 6AL-4V" doesn't tell you specifically what the actual mechanical properties are. 

STA
http://www.matweb.com/search/DataSheet.aspx?MatGUID=b350a789eda946c6b86a3e4d3c577b39

STA Bar
http://www.matweb.com/search/DataSheet.aspx?MatGUID=f87a4a1c92d34da2b1ecde4e4dec7a73

Annealed
http://www.matweb.com/search/DataSheet.aspx?MatGUID=a0655d261898456b958e5f825ae85390

Annealed Bar
http://www.matweb.com/search/DataSheet.aspx?MatGUID=10d463eb3d3d4ff48fc57e0ad1037434

ELI Annealed
http://www.matweb.com/search/DataSheet.aspx?MatGUID=c4297fb8f1094da189732c224e3be1ed

As you can see, are all "6AL-4V", but no two have the same mechanical properties.


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## octaf (Oct 24, 2009)

Marduke said:


> Just saying "Ti 6AL-4V" doesn't tell you specifically what the actual mechanical properties are.
> 
> STA
> http://www.matweb.com/search/DataSheet.aspx?MatGUID=b350a789eda946c6b86a3e4d3c577b39
> ...


 
Now, thank you Marduke for the information !!! :thumbsup:

I'm very interested in this subject, and still learning.

Now I understand that what I have dealt with doesn't represent the whole spectrum of 6al-4v Ti's.

You must be the real expert on this.


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## octaf (Oct 24, 2009)

Marduke said:


> STA
> http://www.matweb.com/search/DataSheet.aspx?MatGUID=b350a789eda946c6b86a3e4d3c577b39
> 
> STA Bar
> ...


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## tino_ale (Oct 24, 2009)

octaf said:


> You're definitely right, Ku !
> 
> 6-4 Ti's are much harder to machine than CP Ti's. Big difference.



I am surprised about this statement. I remember Don once mentioned CP is softer indeed, but gets kind of "gummy" when machined, making it a pain to machine. I only read about Ti 6/4 being a beautiful material to machine, except for drilling.

The fact that a softer material is easier to machine compared to a harder one is a common assumption, but from what I read here on CPF, not very true. It really boils down to how the material behave under a machining operation.

Also read that for newbies learning to machine, 6061 Al was definitely not the best choice of alloy. Soft indeed but on the gummy side too.


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## jirik_cz (Oct 24, 2009)

With all these cheap titanium flashlights on the market they basically lost their exclusivity. 

Is a cheap low grade titanium alloy any better than aluminum alloy? AFAIK it has higher temperature and electrical resistance and is heavier (or at least the "titanium" flashlights are heavier).


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## tino_ale (Oct 24, 2009)

Why Ti has been discussed many times over and over...
Basics : rust proof, tough, beautifull raw machine finish, finish easy to restore, nice touch to the skin... Disadvandages as lower thermal and electrical conductivity have been proven to be perfectly viable and outweighted in many's opinion.


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## octaf (Oct 24, 2009)

tino_ale said:


> I am surprised about this statement. I remember Don once mentioned CP is softer indeed, but gets kind of "gummy" when machined, making it a pain to machine. I only read about Ti 6/4 being a beautiful material to machine, except for drilling.


 
Hi, tino_ale;

A little bit gummy, but not that gummy. Easily workable with normal tool bits.

But I had to be really careful with 6-4 Ti's, not really easy to machine in my experience.


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## berry580 (Oct 24, 2009)

Lower titanium grade = lower cost
Easier to work = less labour cost 

. ' . exponentially lower total cost when taking into account these lights are mass produced while most titanium lights in the past are custom.


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## Morelite (Oct 24, 2009)

compasillo said:


> _Only_ 90% Ti is what a standard alloy has. Ti6Al4V is included in the group named Grade 5, commonly used in surgery, piercing, glasses, and an infinity of items denominated under a "titanium made of" tag. A pure commercial Titanium alloy has a 99% Ti (Grade 2) and it's for heavy duty stuff (higher price). I don't expect a pure Titanium alloy in these flashlights.
> Regarding the slight difference in density between a pure and a standard alloy it would be as small as it never would explain such a big difference in weight and even much less in price.
> 
> Whatever it was the alloy, I'll end purchasing it if I like the flashlight. that's for sure


 CP (grade 2) Ti is cheaper and softer than Grade 5. Actually grade 5 is used when "heavy duty" is required.


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## compasillo (Oct 25, 2009)

Morelite said:


> CP (grade 2) Ti is cheaper and softer than Grade 5. Actually grade 5 is used when "heavy duty" is required.




Good to know that :thumbsup:. 
So pure titanium alloys will be worse than standard ones... That could explain the "cheap" new generation of Ti flashlights


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## kwkarth (Oct 25, 2009)

compasillo said:


> Good to know that :thumbsup:.
> So pure titanium alloys will be worse than standard ones... That could explain the "cheap" new generation of Ti flashlights



Do you realize what you're saying? What is a "pure" Titanium "alloy?"

It's either pure Titanium or it's an alloy of something else and titanium.


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## alpg88 (Oct 25, 2009)

there is lots of free titanium in middle eastern sands, in form of soviet aircraft parts, who knows may be someone salvaged it and sold,


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## compasillo (Oct 25, 2009)

kwkarth said:


> Do you realize what you're saying? What is a "pure" Titanium "alloy?"
> 
> It's either pure Titanium or it's an alloy of something else and titanium.




Yes, it seems a contradiction in terms, but "Pure titanium" are commercially named alloys with = or > 99% Ti. 
The 1% of the remaining contents are other metals, so they are, in fact, alloys.


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## KowShak (Oct 26, 2009)

compasillo said:


> Yes, it seems a contradiction in terms, but "Pure titanium" are commercially named alloys with = or > 99% Ti.
> The 1% of the remaining contents are other metals, so they are, in fact, alloys.



Although "commercially pure" may contain other elements, they are there because the refinement process can not remove them (at reasonable cost) so they are impurities, the biggest constituent of which is usually oxygen. Titanium alloys by contrast have other elements deliberately added in measured amounts to give the material different properties.


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## compasillo (Oct 26, 2009)

KowShak said:


> Although "commercially pure" may contain other elements, they are there because the refinement process can not remove them (at reasonable cost) so they are impurities, the biggest constituent of which is usually oxygen. Titanium alloys by contrast have other elements deliberately added in measured amounts to give the material different properties.



*Alloy groupings*

There are basically three types of alloys distinguished by their microstructure:
*Titanium* - Commercially pure (98 to 99.5% Ti) or strengthened by small additions of oxygen, nitrogen, carbon and iron. The alloys are readily fusion weldable.
*Alpha alloys* - These are largely single-phase alloys containing up to 7% aluminium and a small amount (< 0.3%) of oxygen, nitrogen and carbon. The alloys are fusion welded in the annealed condition.
*Alpha-beta alloys* - These have a characteristic two-phase microstructure formed by the addition of up to 6% aluminium and varying amounts of beta forming constituents - vanadium, chromium and molybdenum. The alloys are readily welded in the annealed condition.
Alloys which contain a large amount of the beta phase, stabilised by elements such as chromium, are not easily welded.
Commonly used alloys are listed in Table 1 with the appropriate ASTM grade, the internationally recognised designation. In industry, the most widely welded titanium alloys are the commercially pure grades and variants of the 6%Al and 4%V alloy.


_copied from http://www.twi.co.uk/content/jk24.html_


This is talking about "additions" not impurities, wich makes a difference_..._
In fact, Grades 1-2-4 are named as Commercial Pure Titanium and they are alloys (with several amounts of O added), Grade 7 is also named CP Ti but it's an alloy with O and Pd... 

Seems that CP Ti is just a naming rule but, depending on the source, everyone of us can get a varied info... :candle:


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## kwkarth (Oct 26, 2009)

compasillo said:


> Yes, it seems a contradiction in terms, but "Pure titanium" are commercially named alloys with = or > 99% Ti.
> The 1% of the remaining contents are other metals, so they are, in fact, alloys.



Thanks!! At last, it makes more sense.


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## easilyled (Oct 26, 2009)

Although its very interesting, isn't this discussion purely academic rather than of practical value? 

Aren't the advantages and disadvantages of Titanium compared to Aluminium the same regardless of the grade of alloy?

Sure, some are harder and stronger than others, but isn't it true that even the commercially pure grades of Ti alloy are more than strong enough for flashlights and considerably stronger than their Aluminium counterparts?

Just like bins of leds, we have to take the word of the manufacturer on the grade of Ti, because without very expensive and sophisticated equipment, we are never going to be able to tell otherwise.


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## BVH (Oct 26, 2009)

I remember my Titanium bike frame tubes being made with something like 5Al, 3.5Va and then the dropouts were the 6AL, 4 Va because the latter was stronger. I don't remember the exact frame tube numbers, though


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## compasillo (Oct 26, 2009)

easilyled said:


> Although its very interesting, isn't this discussion purely academic rather than of practical value?
> 
> Aren't the advantages and disadvantages of Titanium compared to Aluminium the same regardless of the grade of alloy?
> 
> ...




That's certainly right. And a very elegant way to sum up all about this discussion.
Well said. 
:thumbsup:


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## KowShak (Oct 26, 2009)

compasillo said:


> _copied from http://www.twi.co.uk/content/jk24.html_
> 
> This is talking about "additions" not impurities, wich makes a difference_..._
> In fact, Grades 1-2-4 are named as Commercial Pure Titanium and they are alloys (with several amounts of O added), Grade 7 is also named CP Ti but it's an alloy with O and Pd...
> ...


 
Wikipedia disagrees with that, to quote...

The ASTM defines a number of alloy standards with a numbering scheme for easy reference.

*Grade 1-4* are unalloyed and considered commercially pure or "CP". Generally the tensile and yield strength goes up with grade number for these "pure" grades. The difference in their physical properties is primarily due to the quantity of interstitial elements. They are used for corrosion resistance applications where cost and ease of fabrication and welding are important.
http://en.wikipedia.org/wiki/Titanium_alloy

We can probably have a good argument about which is right, however as easilyled points out, I don't think the argument adds too much to the thread. A metal supplier would be a good source of information on this, generally metal suppliers understand the product they're selling pretty well.


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## compasillo (Oct 26, 2009)

@KowShak

At this moment the subject is kinda boring me buddy. I don't want to go on discussing about what is an alloy or not. 
Wikipedia is not the more reliable source of info, however. 
Nevermind. I think the subject is worn out.

As I posted before, Easilyled has summed up the things very well. 
Nothing's left to be said, IMHO

Cheers!


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## bmstrong (Oct 26, 2009)

Fasinating.


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## precisionworks (Oct 26, 2009)

> Wikipedia is not the more reliable source of info


+1

Half the information is incomplete, the other half incorrect 

There are decent metals books, the best IMO is Metals Handbook Desk Edition. My copy, sitting right next to the keyboard, gets more use than any other book in the tech library except Machinerys Handbook. The Ti section makes for good reading, as do the sections on carbon & alloy steels, cast irons, aluminum, tool materials, etc. Well worth the small cost, and a hundred times better than the info on Wiki.


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## fnj (Oct 27, 2009)

Back to the original question. Nobody has really pointed out that the cost of the materials that go into a flashlight casing is almost a negligible part of the selling price, whether it be plastic, aluminum, or titanium.

The price of aluminum sheet is about $0.25 to $1.25 for 4 ounces
[*].
For C.P. titanium sheet it is about $3.75 to $12.50 for 4 ounces
[*].
(I don't have figures handy for tube and rod, but it will probably be similar)
(I strongly suspect prices within China are certainly much less)
(of course small quantity retail will be somewhat more than these contract prices)

Four ounces gives plenty of margin for machining waste to end up with a simple tubular CR2 or AAA light, unless you are doing something crazy like drilling and boring your own solid rod to make the tube. Don't get me wrong, crazy is good and I respect crazy, but the cheaper lights are usually pretty tubular in shape and would be well suited to starting your machining from tube stock for the barrel, and probably the heat sink slug inside the head is not even going to be titanium; copper would serve admirably.

For something like the Ra Clicky, a comparative brick poophouse (in a decidedly GOOD way!), you might start with twice that amount or a bit more if indeed it is drilled and bored, as I suspect may be the case given its fairly exotic shape with tapers. Or perhaps very thick walled tubing to give you a head start.

When you consider that the Ra Clicky sells for around $600, it is very clear indeed that not much of that could be the cost of the raw material. You are paying for the cost of machining, the scrap that is sacrificed, the wonderful engineering in every regard, and most of all the jewelry-like cachet of titanium.

Same thing for the smaller Muyshondt Aeon at around $300.

I'm pretty sure both of these are made from C.P Grade 2 titanium.

BTW, my machinist acquaintenances with the experience tell me titanium, even Ti-6Al-4V Grade 5 high strength alloy, is not difficult to machine as long as you use proper techniques and appropriate tooling. It is widely used in the ocean equipment field.

~~~~~~~~~~
[*] http://resources.metapress.com/pdf-preview.axd?code=17711985wr0367l2&size=largest


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## precisionworks (Oct 27, 2009)

> even Ti-6Al-4V Grade 5 high strength alloy, is not difficult to machine


That all depends on how you define difficult. Machinability ratings are the easiest way to compare how easy or how difficult a material is. AISI B1112 is the "standard" and is assigned a 100% MR. The machinability of Ti 6 4 is rated at 22% of B1112.

Impossible - no way. Difficult - no doubt :nana:


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## neninja (Oct 27, 2009)

For flashlights the use of pure Ti alloys is not really necessary. They are for aerospace type applications where the material needs the strength of steel but light weight to handle high stresses / temperatures or exhaust systems where there are extremely high temperatures involved (although other alloys such as inconel are arguably better).

The best aluminium flashlights will be tough enough to survive all real world events.

For flashlights, titanium is surely all about pose value rather than function. Titanium looks great and has greater kudos.


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## easilyled (Oct 27, 2009)

neninja said:


> For flashlights, titanium is surely all about pose value rather than function.




You know, this is really not true at all. Ti has many practical benefits, which have been stated in countless threads, compared to Al.

It also has some disadvantages which again have been well documented.

I don't think we wan't to turn this into another Ti vs. Al Thread because a search will reveal about 15 or 20 of them!


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## fnj (Oct 27, 2009)

easilyled said:


> Although its very interesting, isn't this discussion purely academic rather than of practical value?
> 
> Aren't the advantages and disadvantages of Titanium compared to Aluminium the same regardless of the grade of alloy?
> 
> ...



To answer the question, no, it is not true that C.P. titanium is superior to aluminum in strength or rigidity (Young's modulus) for a given weight. I was pretty surprised by this myself. Ti-6Al-4V is another kettle of fish; it has very good strength to weight properties (but no better in terms of stiffness to weight).

And in terms of thermal conductivity, titanium is simply terrible.

OTOH, both C.P. titanium and titanium alloy have superior hardness to aluminum. Of course the monster advantage is that titanium is massively more resistant to corrosion, including ocean water. As well as being surpassingly beautiful.

The following figures are for 6061-T6 and C.P. Grade 2 titanium in that order; the second pair of numbers is normalized to density 1.0:

Density, g/cc, 2.7, 4.51
Ultimate tensile strength, MPa, 310, 344 (115, 76)
Tensile yield strength ,MPa, 276, 275-510 (102, 61-113)
Young's modulus, GPa, 68.9, 105 (25.5, 23.28)
Knoop hardness, 120, 170
Elongation, %, 12, 20
Thermal conductivity, W/m-Kg, 167, 16.4

Note the extreme variation in titanium tensile yield strength.

~~~~~~~~~~
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061T6
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MTU020


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## McGizmo (Oct 27, 2009)

fnj said:


> ....
> 
> And in terms of thermal conductivity, titanium is simply terrible.
> 
> ......



I would consider this a meaningful comment if



our hands were made of aluminum or silver or copper and capable of quickly wicking away the heat generated at the source.
The LED's and electronics were at serious risk because of the thermal conductivity of the flashlight material when it is titanium
In terms of machinability of Ti, what is probably most important is the consistency of physical properties from batch to batch of material used. Be it CP or 6-4, if you get your system dialed in on the material at hand only to find that the next batch of material misbehaves, it's a *****! The machine shop I use has encountered better consistency from their suppliers when they use 6-4 and this is likely due to more stringent controls and adherence to specs for the alloy as opposed to those applied to CP. Tool wear and machine time are the real expenses when it comes to Ti, IMHO.

It seems the question of lower grade of Ti coming to market is not at issue as much as lower cost of titanium products coming to market. There may be a premium of 20% for 6-4 over CP but this differential in material cost is not significant in the final picture. I think labor and manufacturing costs are more significant.

I know I can't compete with China on price, regardless of the materials involved. It has been my experience in the past that certain materials were not available in China but I have no idea how this may or may not have changed over time. In regards to Ti and its alloys, It was my impression based on years past that they gained their experience with Ti from former Soviet Union sources in which different alloys from the US alloys were developed and perfected. Different recipes as it were.

The level of significance based on physical properties of these metals varies as based on design, application and use. Out of context, the numbers have no foundation of significance. 

In context, I seek certain abilities from a light and its design. I seek to maximize the neglect-ability and abuse-ability of a light. I have found that the use of titanium has allowed me to reach much higher levels in these abilities. I expect that others can bring to market lights in titanium that also enjoy these greater abilities but it's not a given as based solely on material selection. I have seen some designs where I believe the thermal issue _is_ of significance. But then I have seen designs using aluminum where I also felt the thermal issue was being overlooked. :shrug:


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## precisionworks (Oct 27, 2009)

> Tool wear and machine time are the real expenses when it comes to Ti


+1

I can't locate a machinability rating (MR) for Type 6061, but it is at least 200, compared to the standard. Contrast that with a MR of (about) 20 for Ti 6 4 and every operation in Ti takes about 10X as long as it does in aluminum.

The 10X factor is not exact, but it isn't far off based on the sfpm at which the material can be machined. Figure 2000 sfpm for aluminum, 200 sfpm for Ti. Whether run on a small manual lathe or a high powered CNC machine, the Ti part will take 10X longer than the aluminum part.

Ti loves to eat tooling, especially drills that are not fed with high pressure (1000 psi) coolant. Doesn't matter if the drill is solid carbide or inserted, unless the chip heat can be removed quickly the carbide binder starts to soften - what the engineers call plastic deformation. Turning & boring operations are much easier on tooling, as long as the insert can somehow be cooled.

It isn't difficult to machine, as long as you have the horsepower to keep continuous chip flow + enough coolant capacity to keep the tooling from melting ... sorry, plastic deformation


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## easilyled (Oct 27, 2009)

fnj said:


> To answer the question, no, it is not true that C.P. titanium is superior to aluminum in strength or rigidity (Young's modulus) for a given weight.



Perhaps its not stronger per unit weight, but its strength per unit volume is far more relevant when comparing 2 flashlights of the same dimensions.
Clearly CP Ti is stronger per unit volume than that of Al from your figures.
Therefore an Al PD-S will not be as strong as a CP grade Ti PD-S.


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## TranquillityBase (Oct 27, 2009)

fnj said:


> And in terms of thermal conductivity, titanium is simply terrible.


 
I would consider the above a true and reasonable statement.

Given two lights of *identical* design, including the internals, one made from Ti, and the other made of aluminum...The aluminum light will do a better job of moving/distributing heat to a greater area, where the Ti light will in essence capture/localize the heat generated, and the heat will *slowly* be distributed throughout the mass of the light.

In the grand scheme of things, it really doesn't make much difference, _providing_ said Ti light is driven at/has a low/realistic/usable/reasonable drive level.


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## fnj (Oct 29, 2009)

easilyled said:


> Clearly CP Ti is stronger per unit volume than that of Al from your figures.


It's not that simple, because the yield strength for CP Grade 2 is all over the place. The starting figure is exactly the same as 6061-T6. So unless you are sure the stuff you will get when you order the titanium is more toward the upper end of the range, you will be disappointed, because it will be heavier than 6061-T6 and NO stronger. On the other hand, EVERY piece of certified 6061-T6 is going to be at least as strong as the figure given.

Anyway, even if it is stronger for the same metal volume, that's not very noteworthy. So the titanium version is heavier and stronger. Big deal. Stainless steel is also heavier and stronger.


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## easilyled (Oct 29, 2009)

fnj said:


> It's not that simple, because the yield strength for CP Grade 2 is all over the place. The starting figure is exactly the same as 6061-T6. So unless you are sure the stuff you will get when you order the titanium is more toward the upper end of the range, you will be disappointed, because it will be heavier than 6061-T6 and NO stronger. On the other hand, EVERY piece of certified 6061-T6 is going to be at least as strong as the figure given.



Actually it *is* very simple.

You seem to have forgotten that Tensile Yield Strength was only one amongst quite a few other indicators of strength that you quoted.

*All *the other indicators that you quoted for strength per unit volume were higher for CP Ti compared to Al. 

Regarding Tensile Yield strength, the salient point however is that its *average* (mid-point) value is *also* much higher for CP Ti than Al. 

The likelihood of having a piece of CP Ti at the very bottom of the Tensile yield strength range is extremely small, but even then *all the other criteria for strength* are significantly higher with CP grade Ti.

In case you've already forgotten let's refresh your memory with your own figures shown in red below :-

Ultimate tensile strength, MPa, Aluminium 310, CP Grade Titanium 344 *
so CP Grade Titanium has higher Ultimate tensile strength*

Tensile yield strength ,MPa, Aluminium 276, CP Grade Titanium 275-510 (Midpoint = 392.5)
*so CP Grade Titanium nearly always has higher Tensile yield strength and its midpoint is much higher*

Young's modulus, GPa, Aluminium 68.9, Titanium 105
*so CP Grade Titanium has a higher Young's modulus.*

Knoop hardness, Aluminium 120, Titanium 170 
* so CP Grade Titanium has a higher Knoop Hardness.*

You used your figures to try to disprove that CP Ti is stronger than Al, but unfortunately for you, they do the opposite.




fnj said:


> Anyway, even if it is stronger for the same metal volume, that's not very noteworthy. So the titanium version is heavier and stronger. Big deal. Stainless steel is also heavier and stronger.



Hmmm .... seems like you're changing your tune, by starting to admit that maybe CP Ti is stronger after all.
Funny how Alloy strength is not such a big deal anymore. While you thought that you were correct, it sure seemed quite important to you.
By the way Titanium is much lighter than Steel even though its heavier than Aluminium.


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## fnj (Nov 9, 2009)

Just want to mention because I don't want to take easilyled's bait does not mean I think easilyled has meaningfully negated anything I pointed out. Let him have the last word since that seems to be the object. If anyone else is genuinely interested in any of this stuff, I'll be happy to take a PM.


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## easilyled (Nov 9, 2009)

fnj said:


> Just want to mention because I don't want to take easilyled's bait does not mean I think easilyled has meaningfully negated anything I pointed out. Let him have the last word since that seems to be the object. If anyone else is genuinely interested in any of this stuff, I'll be happy to take a PM.



fnj, the object is to establish the facts. 
If you consider it to be baiting you because I pointed out that you were misrepresenting them, then so be it.
The figures (your own) are here for everyone to see and draw their own conclusions.
You can pretend that 2+2=5 if you want to but don't expect me to buy into that.


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## tino_ale (Nov 9, 2009)

What these numbers say is that CP Ti is stronger than 6061-T6 on all quoted mechanical strength indicators; except in tensile yield which can be higher or in worst case, only equal to 6061-T6 Al.

Now whether the gain in mechanical properties is worth the price and weight is up to the buyer to decide.

I don't see why there should be an argument about this precise question 
CP Ti IS stronger than 6061-T6 Al per unit volume. By how much and how relevant each strengh indicator is for a given application is another matter entirely.


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