Irish,
I doubt the Aluminum case will sag in the 7" direction, so the 15" length is the one in question. Are you supporting it with feet on the extreme edges? or will the feet be placed more centrally which will support the load better. BTW, the 15 lbs. will not be localized to a small spot in the center of the chassis it will be spread out. So IMO I would choose the Aluminum chassis as it's easier to work with and a better heat sink.
I doubt the Aluminum case will sag in the 7" direction, so the 15" length is the one in question. Are you supporting it with feet on the extreme edges? or will the feet be placed more centrally which will support the load better. BTW, the 15 lbs. will not be localized to a small spot in the center of the chassis it will be spread out. So IMO I would choose the Aluminum chassis as it's easier to work with and a better heat sink.
where sagging in an aluminum chassis can be a concern, i use 15 mm angle stiffeners also of aluminum...
where grounding is a concern due to oxidation, i use bolts /studs on several points of the chassis, and block them out prior to powder coating...
i use a gage #16 aluminum for most of my chassis builds, and in some cases, 2 to 2.5mm...
i have an ongoing project where i will use a copper sheet 1.5mm thick...
where grounding is a concern due to oxidation, i use bolts /studs on several points of the chassis, and block them out prior to powder coating...
i use a gage #16 aluminum for most of my chassis builds, and in some cases, 2 to 2.5mm...
i have an ongoing project where i will use a copper sheet 1.5mm thick...
Hi everyone
I did an AB-test today. Steel case vs aluminium case. Else everything exact the same. No measurement data, just my ears for hearing.
I hear no difference. This is not to say that other people with better hearing may detect difference. This is not to say that other electronic design and set up will produce differences in sound.
But as far I see (hear), to me at least, there is no difference if one use steel or aluminium case. If you have other experience, please share.
I did an AB-test today. Steel case vs aluminium case. Else everything exact the same. No measurement data, just my ears for hearing.
I hear no difference. This is not to say that other people with better hearing may detect difference. This is not to say that other electronic design and set up will produce differences in sound.
But as far I see (hear), to me at least, there is no difference if one use steel or aluminium case. If you have other experience, please share.
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My first amplifier chassis was plywood.
Class A, regulated PSU, phono input. About no hum.
Preventing oxidation on aluminum???? Totally impossible; aluminum always has an oxide layer on the surface.
That is why mercury can eat through aluminum. It removes the oxide layer that forms immediately when aluminum is exposed to air
and allows the oxidation to continue until the aluminum is consumed.
Mercury Eats Aluminum! | Science-Based Life
That is why mercury can eat through aluminum. It removes the oxide layer that forms immediately when aluminum is exposed to air
and allows the oxidation to continue until the aluminum is consumed.
Mercury Eats Aluminum! | Science-Based Life
Which is why all exposed aluminum on aircraft must be coated. Which I learned at RockwellCollins. I was working on a new product and it worked fine,passed all tests, until you put the cover on. Even then it worked until you put in the last screw, it did not mater which last screw you put in ( out of about 26 )
but as soon as you put it in it would fail.That is when I found out that they had coated the aluminum chassis and covers with a non conductive coating to meet FAA requirements. The fix was to replace a non-shielded inductor with a shielded one. Strange things happen at 4.3GHZ. Also it worked if you removed the coating from the aluminum.Yes, it worked with the engineering test cover ( no coating ), but not with the production cover. ( coated ). Fun.
but as soon as you put it in it would fail.That is when I found out that they had coated the aluminum chassis and covers with a non conductive coating to meet FAA requirements. The fix was to replace a non-shielded inductor with a shielded one. Strange things happen at 4.3GHZ. Also it worked if you removed the coating from the aluminum.Yes, it worked with the engineering test cover ( no coating ), but not with the production cover. ( coated ). Fun.
Aluminium oxyde.
I experimented on this on metal skis of the 1960 Winter Olympics technology.
Because the top plastic protection was shot from rough skiing, I removed it all, the top was then bare aluminium. Skying became impossible with snow sticking there.
So I went into putting an epoxy layer. Aluminium oxde was troublesome.
I finally found a working procedure.
Working with gloves and eye protection.
Dip a ski in liquid soda NaOH. This does scrape out the oxde layer, exposing bare aluminium.
Quickly rinse with clear water.
Quickly spread the surface with epoxy.
I had to be very quick because the oxde came back very fast.
To equalize for a smooth layer, a slab of glass hapened to work fine.
Those skis became skiing usable for more years to save much better ones from rough handling.
One good thing about those obsolete skis was: They gave me, excellent training because they are terrible on difficult snow conditions. It is tolerance zero with those, they readily tell what's wrong.
All this to say, the Aluminum oxyde rebuids extremely fast.
And NaOH is a best Al oxyde remover, about the only Al oxyde solvant.
I experimented on this on metal skis of the 1960 Winter Olympics technology.
Because the top plastic protection was shot from rough skiing, I removed it all, the top was then bare aluminium. Skying became impossible with snow sticking there.
So I went into putting an epoxy layer. Aluminium oxde was troublesome.
I finally found a working procedure.
Working with gloves and eye protection.
Dip a ski in liquid soda NaOH. This does scrape out the oxde layer, exposing bare aluminium.
Quickly rinse with clear water.
Quickly spread the surface with epoxy.
I had to be very quick because the oxde came back very fast.
To equalize for a smooth layer, a slab of glass hapened to work fine.
Those skis became skiing usable for more years to save much better ones from rough handling.
One good thing about those obsolete skis was: They gave me, excellent training because they are terrible on difficult snow conditions. It is tolerance zero with those, they readily tell what's wrong.
All this to say, the Aluminum oxyde rebuids extremely fast.
And NaOH is a best Al oxyde remover, about the only Al oxyde solvant.
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Google says: Steel is 3x stiffer for the same thickness. Your 1.3mm chassis is compared to 20 guage which is 0.9mm thick and stiffness scales as the cube of thickness. The steel chassis will be stiffer. Be careful with handles which can distort surrounding metal if the stress id concentrated.
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As mentioned above, aluminum quickly gets its own oxide protective layer.
BUT at a chassis grounding point you have different metals in contact: aluminum/iron/solder/copper , so yes, it´s good to add a dab of thick vaseline to insulate the whole battery from air oxygen and dampness.
The telephone guys always cover their outside exposed contacts with thick vaseline, I guess they know something
They have much better:The telephone guys always cover their outside exposed contacts with thick vaseline, I guess they know something
I cannot find the reference.....Doh ! I forgot the exact name for it.
It is a tiny capsule ( flat, round ) filled with a anti corrosion liquid, with two holes to insert two wires that get connected and locked inside. Perfectly air tight and corrosion proof.
This is how they connect phone lines inside a water proof container put underground.
EDIT: 3M UR-BOXED IDC Connectors - Crescent Electric Supply Company
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3M Scotchlock
No need for a crimp tool. It is push in and forget.
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