Chassis thickness

[rsumperl]

Greetings everyone,
What is the general consensus on a 12"x8"x2.5" chassis that is made from .090 aluminum? Will it withstand 10 lbs of iron?
Here's the vendor: GUITAR AMPLIFIER CHASSIS'

Thanks,Ray

[nic6paul]

I have used some aluminum of that thickness. I had a slight sag so I bought some aluminum channel and cut it to run the length of the chassis and it definitely help stiffen up the top. I used two pieces of channel so that both sides of transformers were supported.

[rsumperl]

Would a steel chassis from Hammond be a better choice? I believe their steel chassis is only .036" thick. Would I be in the same boat? Can .036" steel be stronger then .090" aluminum?

[nic6paul]

Sheet metal materials
Check out this site...scroll down to where you see this:

Aluminum sheet vs steel sheet

The following table gives a quick point of reference when you need the approximate thickness of aluminum sheet to use in replacing steel sheet. The designated aluminum thickness will give you about the same stiffness. Or, putting it another way, the deflection will be about equal. As a rule of thumb, plan on using an aluminum sheet about 40% thicker than steel. Since aluminum weighs only 1/3 as much as steel, this means that the equivalent aluminum sheet will weigh only half as much as the steel sheet it replaces.

There is a table there.

[rsumperl]

So according to the chart, .090 aluminum is stronger than .036 steel. How will aluminum paint?

[56oval]

Originally Posted by rsumperl

So according to the chart, .090 aluminum is stronger than .036 steel. How will aluminum paint?

Hi
You will need to etch prime the alloy first before under coating .Some high fill primers have an etch in them but UI would still etch separately .
Also look at different grade's of aluminium different grades will be stiffer .

The other thing you could do is use another sheet/plate on top to get the required stiffness ,even use a different ferrous or non ferrous material .

Cheers

[Loren42]

Originally Posted by rsumperl

So according to the chart, .090 aluminum is stronger than .036 steel. How will aluminum paint?

Unless you use a special primer like zinc chromate, painting is not good. The primer is very caustic.

Alternatives are powder coating or anodizing.

[SY]

Powder coating is pretty easy and works well. If I remember correctly, AR2 did a tutorial here a couple of years ago.

[boywonder]

Originally Posted by 56oval

Also look at different grade's of aluminium different grades will be stiffer .

Cheers

Stiffness for a given material is determined by it's elastic modulus (Youngs Modulus), and virtually every grade of wrought aluminum alloy has an elastic modulus of about 70,000 MPa +/-. The different AL alloys have different yield strengths and differences in other material properties, but they all have roughly the same stiffness for a given thickness.

[Richard Ellis]

The agreed upon upper limit of a chassis thickness is about 2mm. Anything thicker than that most sockets will not have a long enough supplied thru-bolt. Clearances to the pins gets really tight at that limit.

__________________________________________________ ______Rick.........