aluminum weight formula

[sHooTer296]

Im a complete n00b to excel and I really need some help.... I need
formula to tell me how much certain amounts of sheet aluminum weigh.
know a square foot of 1/8" aluminum weighs 1.8lbs. Basically I want t
type in the amount of square feet and get the weight. This may help to
a 60" X 144" sheet of 1/8" aluminum weighs 104.76lbs.

Thanks in advance,
Anthon

 

[FSt1]

hi,
there is something wrong with your numbers or my brain.
you say that a square foot of alumimun weighs 1.8 lbs and a sheet of
5ft(60in) by 12ft(144in) weights 104.76. when i do the math, i keep getting
108 lb.
the math is simple.
in cell A1 enter the standard weight 1.8 lb sq ft (.0125 lb sq in)
in cell B1 enter the length 5 ft (60 in)
in cell C1 enter the width 12 ft (144 in)
in cell D1 enter formula = sum(A1*B1*C1) which equals 108 lb (in sq in or
sq ft)
did i miss something?
FSt1

 

[MartinW]

Hi Anthony

Set this up in a worksheet



A1:- 60

A2:- 144

A3:- 0.125



B1:- =CONVERT(A1,"in","m")

B2:- =CONVERT(A2,"in","m")

B2:- =CONVERT(A3,"in","m")



B5:- =B1*B2*B3

B6:- =B5*2.7*1000

B7:- =CONVERT(B6,"kg","lbm")



I've done this by converting to metric for the calculation then converting

back to Imperial for the result. (metric is so much easier for density

calculations)



The 2.7 figure in B6 is the density of solid aluminium (2.700 grams per
cubic

centimetre). That figure is correct for pure aluminium, if there are alloys
in the

product then you would need to obtain the specific gravity for that product.

The underlying equation here is density = mass/volume or in

this instance mass = volume*density.



Your answer in B7 is 105.35lbs(47.78kg in B6)



Input 12 into A1 and A2 and you will see that a square foot of 1/8 aluminium

Is 1.755787lbs and not 1.8lbs hence the discrepency that FSt1 found.



HTH

Martin

 

[SteveW]

KIS - why convert one way and back.

* Comments in brackets

E1 = 1.8 ( weight of 1 sq foot)
A2 = 12
B2 = 12
C2 = A2 * B2 ( convert to sq inches )
D2 = C2 / 144 ( convert to sq feet )
E2 = $e$1 * D2 ( convert to weight )

Now select A2:E2 and drag down a few rows

Now you can enter various sheets sizes in inches in A3:B3, A4:B4 etc
and you have a visual table of various sheet size /weight combinations for
reference.

Now as others have noticed if you put in 60 * 144 for size, you get 108lbs

So assuming the weight for the 60" * 144" is accurate at 104.76, we can
actually recalculate
the Weight/lb figure

So now in E1, enter = 104.76/60 (total sq foot of knwon weight sample)

Now all the calculations are corrected to use the new weight/lb figure.
And by having the table all previous calculations are now re-calculated.

Steve

 

[MartinW]

Hi Steve,

You're working in square measurements and rounded
values for those square measurements which will always
give you false results in a density calculation.
You have to work on cubic calculations.

1.8lbs is incorrect as my previous post shows.
104.76lbs is incorrect as my previous post shows.

<KIS - why convert one way and back>
Because the metric system makes these calculations
extremely easy and also makes them very flexible
so you can use the one setup for any material
type whether it be aluminium, steel, lead, gold whatever.

Regards
Martin

 

[SteveW]

Agreed, but we don't know the environment for original request.

It's a bit scientific to throw in the exact density of aluminium.

I just took it that there were sheets of aluminium, and they wanted to
know that weight various sizes were.

I think taking the 104.76 as an on site weight is more realistic.

Steve

 

[MartinW]

Hi Steve,

<It's a bit scientific to throw in the exact density of aluminium.>

Yeah, I know it sounds pretty anal, but you do have to be scientific
about these calculations.

I work in a materials testing laboratory and the difference between
a density of 2.700 and 2.713 can translate into very big dollars
on large projects.

Regards
Martin

 

[sHooTer296]

Thanks for the quick and very helpful posts guys, They are much
appreciated!

 

[sHooTer296]

It is 5052H32 aluminum mostly. We make marine fuel tanks and such and
need to figure out how much each weighs(empty). Just wanted to sa
thanks again for all the helpful posts