I wonder if there is any merit in using aluminum foil
duct tape to make a capacitor?
"Airy R.Bean" wrote in message
...
I wonder if there is any mileage to be had from adapting
the numerous junk-mail CD's as the vanes of ATU
capacitors?

1. We already have a form that is circular (no waste) and
with an accurately-positioned central hole.

2. There is a metallic film sandwiched between the plastic.

3. Is this film to thin to stand up to the RF currents that
will spread out across it when charging & discharging?

4. How would we make metallic contact to the film without
destroying the film at the point of contact?

5. Does anybody know the type of metal making up the film, i.e.,
can we solder to it?

6. Is the plastic of a suitable quality? Will it arc-through?

"Radio Man" wrote in message
news:SbyFd.20564$lG.19133@trnddc03...
I wonder if there is any merit in using aluminum foil
duct tape to make a capacitor?

I wonder what the background to you idea is?

New approaches to existing designs should offer one or more of:

Cost savings (cheaper materials, less man hours, ease of manufacture etc)
Better reliability and/or life (not the same thing by the way)
Extra functionality

For most things, the cost of materials is not a cost driver- the cost of the
material in a variable capacitor is dwarfed by the labour and machining
costs.

So, how does using duct tape help?

The CD idea falls flat as, while they may be cheap, the amount of machining
'saved' is mininmal. I suppose if you are totally strapped for cash, out of
work and with time on your hands, they may offer some advantage, but you
end up with a 'product' of inferior quality. Engineers who are driven by
such a penny pinching approach usually end up bankrupting their company as
their products are poor.


--
Brian Reay
www.g8osn.org.uk
www.amateurradiotraining.org.uk
FP#898

"Machining"? What, cutting with a pair of scissors?

There's considerably more machining involved in your
proposal to use etched PCB.

"Brian Reay" wrote in message
...
The CD idea falls flat as, while they may be cheap, the amount of
machining
'saved' is mininmal. I

The proposal to investigate the use of junk-mail CD's
seems to meet your very first criterion.

"Brian Reay" wrote in message
...
New approaches to existing designs should offer one or more of:

Cost savings (cheaper materials, less man hours, ease of manufacture etc)

"Extra Functionality! - What "Extra Functionality" do you
envisage in a variable capacitor?!!!!!

"Brian Reay" wrote in message
...

New approaches to existing designs should offer one or more of:
Extra functionality

You don't seem to have the qualities that makes
for a _REAL_ Radio Ham, OM!

There are no labour costs when you do things for yourself!

There are no machining costs in cutting up a CD with a pair of scissors.

"Brian Reay" wrote in message
...

For most things, the cost of materials is not a cost driver- the cost of
the
material in a variable capacitor is dwarfed by the labour and machining
costs.

Right you are, Mr. bean. Some individuals can't seem to separate their
personal from their business lives. They need to assign a dollar value to
everything. Many of these people, when not at work, do nothing as they
dismiss most leisure time activities as an inefficient waste of man-hours.

"Airy R.Bean" wrote in message
...
You don't seem to have the qualities that makes
for a _REAL_ Radio Ham, OM!

There are no labour costs when you do things for yourself!

There are no machining costs in cutting up a CD with a pair of scissors.

"Brian Reay" wrote:

: "Radio Man" wrote in message
: news:SbyFd.20564$lG.19133@trnddc03...
: I wonder if there is any merit in using aluminum foil
: duct tape to make a capacitor?


well done!

you got a BIG BITE with that one.

Did you notice the word "amature" in the newsgroup title? You might want to
consult a dictionary for the definition of that word.

"Brian Reay" wrote in message
...
Engineers who are driven by
such a penny pinching approach usually end up bankrupting their company as
their products are poor.


--
Brian Reay
www.g8osn.org.uk
www.amateurradiotraining.org.uk
FP#898

"CW" wrote in message
...
Did you notice the word "amature" in the newsgroup title? You might want
to
consult a dictionary for the definition of that word.


No. But, then again, it isn't there so I wouldn't have.

If you meant amateur, that work doesn't not mean 'bodger'. Just because you
are doing something for fun is no excuse not to do it well.

--
Brian Reay
www.g8osn.org.uk
www.amateurradiotraining.org.uk
FP#898