# Next Mod Titanium



## Anglepoise (Dec 10, 2005)

Well I am going to give it a try.
Now all I need is to purchase a 1" round by 4" long, piece of Titanium.
Any ideas on such a small quantity. My regular aluminium supplier just laughed.


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## Fruitjacknix (Dec 10, 2005)

Try this link, buy the foot and make 3 flashlights!!
http://onlinemetals.com/


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## Anglepoise (Dec 10, 2005)

Thanks Fruit.
Their just down the road from me.
Amazing I have not come across them before in my travels.


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## McGizmo (Dec 10, 2005)

It looks like McMaster is not on top of the silly prices of Ti!


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## cy (Dec 10, 2005)

good grief $153 for one foot of 1in. ti

McMasters is right behind at $137


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## Anglepoise (Dec 11, 2005)

There seem to be a number of grades.
# 6AL/4V ELI
# 6AL/4V GRADE 5
# CP GRADE 2

Grade 2 is the cheapest and is meant to machine better.
However the price and problem of getting rid of the heat in the design I am working on , makes me think I should re consider and possibly wait and see how
other member's TI mods work out.
At 1000ma, where is the heat going to go? Even 500ma could cause problems as I want to use a regulated side switch and this will hamper moving heat to the battery compartment.
This seems to be the one negative with TI.


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## nemul (Dec 11, 2005)

wow! that's alot!


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## kongfuchicken (Dec 11, 2005)

There's a seller on ebay for overstock titanium (titanium joe IIRC). He has pretty decent prices on 6Al/4V consumer purity stuff. You guys might want to ceck it out.


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## McGizmo (Dec 11, 2005)

David,

Ti is definitely not a stellar performer in terms of thermal conduction but all is relative I am coming to understand (or at least I think I am.  ) I did a thermal test with my new McLuxIII-Ti and it was comprised of a thermacouple imbedded in the Al heat sink along with another thermally gooped to the surface of the Ti head. I ran the light head, sans battery tube, off the bench supply with the head isolated and standing in still air. I ran the assembly for 15 minutes and it seemed that steady state had been reached or at least very closely approached. Now had the light been complete with the battery tube and battery in place, there wouldhave been more Ti in the thermal system as well as considerably more surface area in contact with the air. This should have resulted in a lower steady state temperature. A graph of this test:








As I recall, based on the Vf at 550 mA I computed about 18 or 19 C/W for this set up between the sink and Ti head. I have not done similar tests with Al components so I don't know how much better the Al would perform but it is clear to me that the thermal escape beyond the light through your hand or in worse case through the air is likely the real bottle neck. :shrug: I was real surprised during the test, at the end, when I took a small circulating fan and brought it over to the light head! What a difference air movement makes!!

At any rate, until proven full of misconceptions, I feel that the McLuxIII T which will be host to an efficient TY0H emitter and driven at 550 mA on high should be reasonably within thermal bounds in most applications. I would be reluctant to push this package with higher currents and less efficient emitters withoutfurther testing and consultation with someone who actually understands the thermal aspects! :green:

Ironically, now that I am starting to feel comfortable in using my favorite metal in flashlight applications, the bloody cost of the material is going through the roof!!!!

BTW, 6-4 can machine about the same as the CP and I suspect it is more a case of its anealed state than the alloy itself. I think Ti's high thermal resistance is a much greater issue in machining the metal than it is a show stopper for use in the flashlights!  Ti has yet to harm a LED for me but it has trashed 100's of dollars in tools and parts!


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## Anglepoise (Dec 11, 2005)

Don.....I was rather hoping you would respond and appreciate the info.
Very encouraging data on the heat situation. Looks allot better than I thought.
Will continue on ......


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## WillnTex (Dec 11, 2005)

Also try Alpha Knife Supply. I have several friends that use them and they seem pretty good. They list a 1" by 11.875" piece of CP-3 (grade 3) for $90 

http://www.alphaknifesupply.com/ti-rod.htm

Another titanium supply 

http://www.halperntitanium.com/ They list 6 AL/4V Titanium Rod up to 1.250"


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## proFeign (Dec 22, 2005)

Hey,

I didn't see it said here but though I've never machined Ti my friend who works full time in a one-off CNC shop has and he said that you have to keep it positively smothered in cutting fluid. It develops an oxide on its surface when scratched in a fraction of a second, which produces a little heat. The problem with machining is that you are exposing quite a lot of it very quickly and the chips/dust are flammable as well and he had a part he was lathing catch on fire dramatically after only some seconds of cutting. 

He said it didn't damage the part but it was scary and had to remove more of the surface to get rid of the discoloration from heat/uneven oxidation.

Anyway, that's the story as I understand it. I guess it's like metallic Na, only less reactive.

-Kelly


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