# Aluminum T6061 vs. T7075?



## Ty_Bower (Jan 30, 2008)

What's the difference? I thought T6061 was a reasonable quality alloy, often used in the manufacture of flashlights. Occasionally, but not often, I'll see a manufacturer using T7075. Is the T7075 better, worse, or just different? Does it really make any difference in a flashlight?


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## Ganp (Jan 31, 2008)

6061 and 7075 are both fine for flashlights. 7075 costs a lot more though.
Here in the UK 6061 is not so common. Our equivalent is 6082.

These pages give the properties of alloys.
http://aluminium.matter.org.uk/aluselect/10_summary_browse.asp




Colin.


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## matrixshaman (Jan 31, 2008)

T7075 is a bit stronger or harder. T6061 is quite strong too and is common in aircraft quality parts. When I was hang gliding nearly all gliders used T6061 for the tubing in them.


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## bmstrong (Jan 31, 2008)

7075 is in my Mchale. 6061 is in my Kifaru's.


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## Anglepoise (Jan 31, 2008)

If you need to machine something with a very thin wall, I would go with 7075T. I have taken it down to a wall thickness of 0.018" and at that thickness you really appreciate its extra hardness.

My lights machined in 7075T seem to stand up to EDC better than the 6061.
Less visible marks etc.


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## jch79 (Jan 31, 2008)

bmstrong said:


> 7075 is in my Mchale. 6061 is in my Kifaru's.



Where have these brands been all of my life? I'm not a hunter or in the military, but as an outdoorsman, the Kifaru stuff especially is still really cool! :thumbsup: Thanks for accidentally hipping me to some new gear! :rock:

john


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## sawlight (Jan 31, 2008)

6061 T6 is a DREAM to machine!! Nice and stringy, leaves a nice finish, easy to polish etc.
7075 is harder, but gummy to machine, it gaulds up easy, harder to get a good finish and really doesn't like o polish. But is less scratch resistant and holds anodizing better.


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## mudman cj (Jan 31, 2008)

There is some information and debate in this thread about alloys other than 6061 and there advantages/disadvantages for flashlights that you might find interesting.


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## BOUT2HUNT (Feb 1, 2008)

I would go with 7075 also, it is more difficult to machine, but I have found that if you use a squirt bottle with a mix of water and Dawn dishwashing soap it works extremely well. It also works well for the drilling process also.


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## frisco (Feb 2, 2008)

The 6061....7075 question comes up all the time in many industries. There is also a T rating to each alloy.

In flashlights..... It doesn't really matter....If 6061 machines better for you.... Use it.

I've built many parts for racing applications (motorcycles, shifter karts, race cars)
These parts have to be as light and strong. If the part keeps failing.... You keep making it bigger and stronger.
In racing you have to predict(or learn the hard way) how the part will fail.

When you make a part, The first thought is....Steel, Aluminum, Ti, Mag, plastics, carbon fiber, etc., etc.

Back to 6061-7075
7075 is harder than 6061, kind of "brittle". Allot of times 6061 is used over 7075 because 7075 will break at a point where 6061 will bend. In most cases a bend is better than a break.

frisco


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## Ty_Bower (Feb 2, 2008)

mudman cj said:


> There is some information and debate in this thread about alloys other than 6061 and there advantages/disadvantages for flashlights that you might find interesting.



Thanks for the reference. That's a very good thread which more than answers all my questions.


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## mudman cj (Feb 2, 2008)

frisco said:


> 7075 is harder than 6061, kind of "brittle". Allot of times 6061 is used over 7075 because 7075 will break at a point where 6061 will bend. In most cases a bend is better than a break.
> 
> frisco



While that can certainly be the case when fully hardened, I would like to add that 7075 can also be heat treated such that it has comparable ductility to 6061 while still possessing greater strength.


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## fxstsb (Feb 10, 2008)

7075, anodizing could be optional.


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