# 6xxx Aluminium, 7xxx Aluminium or Titanium



## Packesel (Feb 1, 2009)

I want to build a flashlight with one P7 LED. It should be driven by 3 x 18650 (parallel). The flashlight should be build like a tank so that it should be made of 6xxx or 7xxx aluminium or titanium. Would it be enough to polish the aluminium surface or do I have to anodise it? It should not become gray after a while. How much more would it cost if the flashlight would be made of titanium? 
At the moment I would prefer a titanium body and a copper heatsink.  Maybe someone has a better solution.

Regards

Packesel


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## PEU (Feb 1, 2009)

Titanium is roost proof, alu needs to be coated, either anodized or nickel-plated. 
Ti is expensive, Alu is cheap. You can compare prices at www.onlinemetals.com not that they have the best prices, but you would be able to compare them from the same vendor. 
Look for TI grade 2 (99.5% pure TI) or grade 5 (6AL4V) which is stronger. 60xx or 70xx Alu are good choices if you plan to annodize, if you go nickel-plate almost any alu alloy will do the trick. 
To give you an idea, nickel plate is heavily used in the petroleum industry to protect machinery, its very good in salty environments. Also its better than HA3 annodize in sharp corners. HA3 is excellent in scratch protection,
If you build your flashlight with thick walls it will be a tank with any of the mentioned materials. 
There you go, now make your own choices 


Pablo
PS: Oh, you wanted opinions? 60xx alu + chemical nickel-plate does the trick for me.


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## Alan B (Feb 1, 2009)

Check the heat transfer characteristics of the metals. Ti is poor, 70xx is fair, 60xx is better, if I recall correctly. If you want to dissipate a lot of heat through the body (and the P7 run hard does), this is a factor in the design.


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## gadget_lover (Feb 1, 2009)

I disagree with Pablo's assertion that aluminum must be coated. A bare aluminum light polishes nicely and stays good looking for a long time. It's really easy to re-polish too.

If you are not planning to anodize, the 2XXX series has some nice properties. I made one from 2011-T3, and it held up well through 3 and a half years of daily use, clipped to my belt and 100% exposed. I'd still carry it if I had not lost it.

https://www.candlepowerforums.com/threads/69661

I never had to polish it. It picked up a ton of super shallow scratches over the years, but still looked good.

Daniel


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## Packesel (Feb 1, 2009)

OK, thanks for your answers. I do not want to reinvent the wheel. So I will take Alu. Maybe I should not produce prototypes with Ti. This could be to expensive. 
I didn 't think of 2xxx Alu, yet. But I' ll take a look at it. It seems to be as good as the other alloys.
Ti and heat transfer... yes, it could really be a problem. The flashlight would be unbreakable but the P7 could damage itself. All show and no substance. This wouldn `t be the tank I thought of. 

Adrian


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## PEU (Feb 1, 2009)

Cool  Debate!

I understood that build it like a thank meant also to be protected from an hostile environment, not the kind of environment a keychain usually withstands.

In that line of tought I suggested coating alu, to compare it to bare ti in the same kind of environment.

I agree on the 2xxx series, machines very well but its not OK for annodizing, thats why I suggested 6xxx 7xxx for this process.

But hey! opinions are just that: opinions, and everyone is entitled to one 


Pablo


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## Boltgun (Feb 1, 2009)

you can get away with the polished AL, or you can blast it and have some KG cote it too. 

Boltgun


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## Packesel (Feb 1, 2009)

Hi Pablo,

I have just visited your homepage. Great flashlights! 



> opinions are just that: opinions, and everyone is entitled to one


Yes, that `s what I wanted to read: opinions and experiences with selfmade flashlights. I am very satisfied with the answers. :twothumbs

I think, I will not anodize the flashlight and see what happens. The proof of the pudding is in the eating.  



> I understood that build it like a thank meant also to be protected from an hostile environment, not the kind of environment a keychain usually withstands.



It will be made for camping. I want to carry one flashlight and not three of four because one could be damaged. 

Adrian


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## gadget_lover (Feb 1, 2009)

When it comes to survivability, the type of metal (and even that alloy) will not make as much difference as attention to the dimensions of the parts. A very thin wall in a place where it take abuse will fail unexpectedly. That includes places like bezels and tail-caps.

The weight of the light also has an impact on your design. If you have a lightweight single cell light you can drop it with little damage even if it's made of brass. Drop a 5 pound light that uses 4 D cells and with a 6 inch head and you are more likely to see some damage.

Pablo is right, for maximum protection from chemical exposure (including the elements) a coating of some sort helps. 

Oh, and don't forget. One flashlight is none when it's time to change the batteries. Two is always better. 4 or more is just fun.

Daniel


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## 65535 (Feb 2, 2009)

Why not stainless steel? It has good properties it's a bit heavy has excellent thermal properties and needs no coating to be corrosion resistant. 

316 or any 300 series is a good choice.


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## Alan B (Feb 2, 2009)

Stainless is nice but it conducts heat poorly and is heavy compared to Al.


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## HarryN (Feb 2, 2009)

gadget_lover said:


> . I'd still carry it if I had not lost it.
> 
> I never had to polish it. It picked up a ton of super shallow scratches over the years, but still looked good.
> 
> Daniel




You lost it ? Yes, I have to admit, that light was nice in bare Al, and I prefer bare Al also, but then again, ano is nice.

My preference is 7050 or 7075. The reasons are simple:
- It machines nicely - better than 6061-T6 IMHO. The chips are easier to deal with from my perspective.
- Hardness and mechanical properties - similar to modest steels
- Thermal - not so far from decent Al
- Nice finish with polish, sanding, or ano

If it is a larger light for carrying in a wet environment, I would sand it with 100 grit sandpaper - one direction, and use as is. This gives a little grip and is easy to fix.

In a very harsh environment - like sea exposure for long periods, Ti probably is a better choice.


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## Blindasabat (Feb 2, 2009)

If you look at the Aluminum guide at onlinemetals.com:

http://www.onlinemetals.com/aluminumguide.cfm

You will see that 5052 & 6262 AL have better corrosion properties compared to other Aluminums, but are not as strong as 6061 & 7000 series. Normal AL will corrode over time left to itself, frequent handling and cleaning after exposure to elements may slow that dramatically. 

6061 is most common and is significantly cheaper than all other grades on McMaster-Carr where I priced out rods and tubes, so it is a more available at good prices. Other grades will cost two to five TIMES as much in some places.


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## Packesel (Feb 2, 2009)

> Why not stainless steel?



It is too heavy for a big flashlight. I will take Al.



> If it is a larger light for carrying in a wet environment, I would sand it with 100 grit sandpaper - one direction, and use as is. This gives a little grip and is easy to fix.



Sounds good. I `m going to think about it. Many of my flashlights are scratched. Maybe this would solve this problem.

Adrian


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