I have home-brewed a number of enclosures. for one of the reasons Wayne cited--
enough weight to keep the piece of equipment stable on the desktop -- I have
settled on brass as my favorite metal. Depending upon the nature of the
project, I sometimes also use copper.
Comparative densities: Brass is 2.00 to 3.15z density of AL 6061 alloy.
Copper is 3.28x. steel is 2.88x. Brass is (depending on which alloys you
choose) roughly 1.1x to 1.2x density of steels.
Advantages of brass and copper versus aluminum and steel:
1. thicker sheets can be cut to size with a table saw using any carbide-tooth
blade, unlike steel (or with a saber saw)
2. machines easily(less drill bit binding than AL, and easier to tap for
threads than AL, which tends to clog threads of taps and cause them to bind and
break). Being harder, brass also holds a thread better than AL.
3. Corner joints can be soldered on projects made from folded sheet copper or
brass.
4. Thicker plate can be bent to form corners more easily than steel, and won't
break when folded 90° (unlike 0.125 thick ness AL).
4. The look is really nice, especially if you live in an older home like I do,
where there's lots of brass built into the house.
Disadvantages:
1. Cost. From the metal supply business where I acquire all of my project
materials out of the scrap piles at waste metal prices, brass and copper are
about twice the cost per pound of AL, which means the metal for any given
project will cost about 6x as much as AL.
2. Fasteners. For esthetic reasons and prevention of galvanic corrosion, I
prefer to use brass or copper fasteners. You can buy copper pop rivets, but not
from many sources. (McMaster-Carr has 'em if your local hardware doesn't.)
3. Maintenance: any brass or copper enclosure will oxidize over time unless
coated with lacquer or painted (e.g. black to match Elecraft line). Or you have
to polish it, which is essentially impossible due to knobs and knob labels.
4. Extrusions (e.g. L shapes for use on edges of box) and almost impossible to
find, so if you need them you have to roll your own.
73
Lew N6LEW
On Feb 25, 2013, at 4:02 AM, Mike K2MK k...@comcast.net wrote:
Hi Jim,
As a point of curiosity here's a posting from Wayne (04/15/2010) describing
the reason for using steel in the P3 enclosure:
/The P3 enclosure is being fabricated entirely from corrosion-resistant
steel (plated before painting) rather than aluminum. Production and
field test units will weigh about twice as much as the prototype you
tried out (about 5 pounds).
Besides making the unit heavy enough to not slide when you push the
buttons, the steel enclosure will reduce EMI generally -- in or out.
The use of steel also makes the enclosure very strong, so that you
could, if you wanted, put a heavy 20 A linear power supply inside to
power the K3, etc. While we don't have any current plan to offer an
optional internal power supply for the P3, some of us (including me)
will be rolling our own. In my case it will free up some valuable desk
space. (Anyone need a Samlex power supply? Pick-up only!)
73,
Wayne
N6KR
/
Jim AB3CV wrote
Just was playing around with a magnet and noticed that the KAT500, KPA500
and P3 all have some of their panels made of steel rather than aluminum.
I've been wondering how to keep some of my little homebrew boxes from
sliding around yet blended with the K-Line feng shui. The steel top of the
P3 looks like it will become the next resting place for a consolidation
box
of boxes and a magnetic base would keep it from sliding around when
buttons
are pressed.
Nice!
jim ab3cv
--
View this message in context:
http://elecraft.365791.n2.nabble.com/Steel-in-some-K-line-enclosures-tp7570327p7570331.html
Sent from the Elecraft mailing list archive at Nabble.com.
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