gdaught6@stanford.edu wrote:
> Roger, Missouri Guy, and others wrote about:
>
> < snip, snip >
>
>
>> Other wise the silicone rubber might be available through automotive
>> stores. It is available through aviation parts suppliers. It's the same
>> stuff they use for engine heat baffles. Might be a tad expensive
>> though. I don't know what they charge for it. Try a search on
>> Aircraft Spruce, or AircraftSpruce, or silicone rubber aircraft engine
>> baffles.
>>
>
> McMaster Carr has it in various thicknesses. I've bought it both "plain" and
> with
> adhesive on one side. Make your chimney out of the plain stuff, and glue the
> seam
> together with a piece of the adhesive stuff.
>
Don't forget to take into account the mounting of the tube and whether
it needs cooling or not.
I looked but couldn't find a data sheet on the GS-31B, but looking at
the photo of the tube I wonder if the standard chimney would work with
that heatsink.
> And note it is SILICONE not silicon. Silicon is an element that is used as a
> substrate
> for most semiconductor devices. Silicones are compounds where the positions
> of
> Carbon atoms are taken by one or more Silicon atoms... hence, silicone
> rubber,
> silicone grease, silicone oil.
>
That's a mistake they make even in the industry.<:-)) It's sorta like
"Styrofoam cups" There is no such thing. Styrofoam is a blue,
trademarked building material.
(Quick Story about Silicon I think might be appropriate)
Back in 1961 I started working for a little start-up owned by a large
chemical company. The office was in an old two story farm house and the
original manufacturing was done in a large cement block garage.
Probably large enough to hold 2 semi tractor trailer combos in each of
two areas. When I started work they had just completed two new
buildings. A two story reactor building with each floor about the size
of a basket ball court (or a tad larger) They were also moving into a
rater large office area with a zoning room about the area of a
basketball court on one end. Poly Silicon rods were about a half inch
in diameter. Ultra pure "Float zoned" rods 1/2" in diameter from the
zoning room sold for $160.00 a *gram*. I left there after 26 years in
instrumentation and went back to college full time. By then the plant
covered an area of about 4 city blocks and was soon to become the
world's largest producer of poly crystal Silicon. Those half inch poly
crystal rods were now so large it took a hoist to lift them and
although they were far more pure coming out of the reactor than that
$165 single crystal from 26 years previous, they sold for only a tad
more than $2 USD a Kilo. Also "industry wide" the single crystal rods,
which were as large as 6" or 8" in diameter (IIRC), were grown in
"crystal pullers"
I don't know the price of either the poly or single crystal today, (and
probably couldn't say if I did) but the industry is using slices
(wafers) of single crystal Silicon are up to 14" or more in diameter.
That plant that was moving out of the garage and farm house covers close
to a half square mile. It became the worlds largest producer while I was
in college and has I believe has doubled in size/capacity at least three
times since then. They are just finishing up a $400 Million dollar
expansion and are already moving into a $1.5 Billion dollar expansion.
http://blog.mlive.com/bctimes/2008/03/one_of_the_biggest_investments.html
(the newspaper got it almost right <:-)) )
A brief history with a couple photos
http://www.hscpoly.com/About%20Hsc/History/hsc_history.htm.
A Google search on Hemlock Semiconductor will produce a wealth of
information.
It's no wonder the high power transistors we use today are so much
cheaper than those limited to much lower power limits just a decade or
two back. Looking at this and I'm beginning to get the itch to build a
legal limit (with plenty of reserve) solid state amp complete with auto
band switching and all the protection circuits.
On the other hand I need to do a bit of work on my old Henry 2K-4 which
is getting a bit noisy and creates a bit too much heat from the tubes. I
get plenty of output on the bird, but the Henry multi meter is erratic.
That's hard to do when the little HL1.5Kfx works so nice. Maybe a pair
of those GS-35Bs would be sufficient and give new life to the 2K-4<:-))
> 73,
>
>
>
> George T Daughters, K6GT
> CU in the California QSO Party (CQP)
> October 3-4, 2008
>
>
BTW, after I graduated from college I was hired by Dow Corning at the
Midland plant, worked for various departments and became a project
manager at the corporate level in roughly 3 to 4 years. The only times
I've ever been back to HSC were in a consulting capacity while working
for corporate as a project manager.
Since retiring I've never been back to either. I loved the jobs and had
a great team working for me when I left, but when I retired I wanted to
go play. I'm glad I did too as just 10 years after retiring I had a
stroke, but a year later after learning to walk again, I only have a
slight limp and have gained a new appreciation for good insurance. <:-))
73
Roger (K8RI)
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|