# Best thickness for aluminium SS



## Resigned User (Jul 4, 2015)

Quick question 
What is the optimal thickness for an aluminium SS? 
Not for the core but completely in alu


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## Viper010 (Apr 21, 2012)

I think if you make it from a factory made slab of 6061 or comparable, 6mm will be fine. If you want top slots, 8mm.

If you want to melt and cast your own, I would go with a minimum of 14mm.

I say this because when you melt and cast at home and not in a tightly controlled industrial furnace, there's a chance of internal impurities, stress cracks and little air voids which obviously diminish strength.

I would also advise, for a home cast product, to clamp it to your work bench, forks sticking over the edge, and hang from the forks some serious weight to test the strength. As in 3-4 times the maximum elastic pull strength you want to put on there.

Bare in mind, I'm not a structural engineer. Statements posted above are merely "guesstimates".


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## Resigned User (Jul 4, 2015)

I wanna try to "cut" one from a 10mm sheet 
Did u think it is enough?


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## Can-Opener (May 11, 2013)

If you like a slim frame it should be great


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## Byudzai (Aug 31, 2013)

10mm is a slim frame but not too slim; ~3/8".  1/2" or 13mm is my preference; gives you a little more room to contour and still pocketable.


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## Phoul Mouth (Jan 6, 2015)

Widget said:


> I wanna try to "cut" one from a 10mm sheet
> Did u think it is enough?


Yeah. that is more than enough.


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## oldmiser (Jan 22, 2014)

I my self like for a all alum frame 5/8" thick....Radius all the edges...

~AKAOldmiser


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## Resigned User (Jul 4, 2015)

Byudzai said:


> 10mm is a slim frame but not too slim; ~3/8". 1/2" or 13mm is my preference; gives you a little more room to contour and still pocketable.


3/8".1/2" how much is it in CM or MM?


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## Viper010 (Apr 21, 2012)

3/8"= ~10mm 1/2" = ~13mm give or take a fraction of a mm. 1 inch =~ 25,4mm or 2,54 cm


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## Chuck Daehler (Mar 17, 2015)

Anything that won't bend under the force of band pull counts as legit. Some like an extremely thin frame that is paracord wrapped, some like, as the jeweler of aluminum frames, Master Byudzai, says, 10mm and over. Why don't you try several several thicknesses and wrap them differently for a variety and a complete set...some covertly flat and some with a little more grip to them? I could see even a 3/4" or 1" frame all radiuse, a little ergo factored in, and comfy. Do you have a water jet guy or do you plan to use a band saw? Band saw blades of course come in metal cutting form which you can change out with your wood cutting one...sure makes cutting fast..otherwise drilling a lot of holes close to but not touching the cut line, and chasing them out with a common hack saw works as one poster demonstrated a couple weeks ago here....rasp, file, sand, polish as usual.

To figure cm and inches, 2.54cm = 1 inch.

To figure for example what mm value is 3/8 inch, multiply 2.54 x 3/8 - - - - 2.54 x 3 divided by 8 - - - - which is on my computer's calculator = 0.95 cm or 9.5mm

Pretty easy once you know the number equivalents.

You see a lot of folks shooting 9.5mm round balls, all that is is 3/8" ammo for example. Once you get hip to metric it'll make more sense. Living in Ecuador we use both metric and English, I much prefer metric, I can figure stuff in my head by moving a decimal point around instead of fiddling with a calculator as I would the English system. 10 mm = 1cm 100cm = 1m 1000cubic centimeters (cc) = 1 liter 1 liter = 1 kg 1000 liter = 1 cubic meter and so on. 1cc of water - 1 gram, 1 liter = 1kg, 1000kg - 1 metric ton and so on...a fantastic system with which to calculate just about anything except when does your mother-in-law shut up.,


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## Resigned User (Jul 4, 2015)

Thx Chuck 
My problem is that I can't find aluminium sheets here in my town so I must buy it on line and I wouldn't buy the wrong one

I know the conversion from inch to CM 
The problem was that I think that Byudzai wrote 3/8.1/2 and not 3/8 and THEN 1/2 (two different numbers) so I'm a little bit confused and ask


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## Byudzai (Aug 31, 2013)

Byudzai said:


> 10mm is a slim frame but not too slim; ~3/8". 1/2" or 13mm is my preference; gives you a little more room to contour and still pocketable.


sorry man, didn't mean to confuse. there's a period after the 3/8" and it was meant to say "10mm is slim.... about 3/8 inch" and then say "1/2" or 13mm is my preference."


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## Resigned User (Jul 4, 2015)

Byudzai said:


> Byudzai said:
> 
> 
> > 10mm is a slim frame but not too slim; ~3/8". 1/2" or 13mm is my preference; gives you a little more room to contour and still pocketable.
> ...


Yep... My mistake... You are correct but I'm not

I found a plate 500mmX500mm and 10mm thickness for about 70 Euro

Price too high?


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## Viper010 (Apr 21, 2012)

Widget said:


> Byudzai said:
> 
> 
> > Byudzai said:
> ...


Price sounds about right to me, and from 50 x 50 cm (almost 20x20 inches) you should be able to make 15-20 nice slingshots!

If you count your labor as hobby time, you could theoretically make your entire investment back selling 2 or 3 of them so I would say that's not a bad investment at all!

Tip of the day: try to keep the protective plastic film on there as long as possible. It'll save you a lot of time sanding and polishing.


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## Resigned User (Jul 4, 2015)

The aluminum that I found is 7075 ...
How is it?


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## Metropolicity (Aug 22, 2013)

Widget said:


> The aluminum that I found is 7075 ...
> How is it?


It is very hard, harder than 6061. You'll spend a lot of time cutting it.


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## Resigned User (Jul 4, 2015)

I hope it is good for slingshot making

Time is not a matter... I have a lot of it


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