4999Re: [loopantennas] Re: BENDING COPPER TUBING
- Mar 2, 2008I seem to recall that the method of filling the tubing with sand was seen in the movie "Flight of the Phoenix" (the original, not the remake) where the model airplane designer was distilling water from barrels of antifreeze, or something like that.
>From: gplynas <gplynas@...>Chris
>Sent: Mar 1, 2008 5:41 PM
>Subject: [loopantennas] Re: BENDING COPPER TUBING
>Hi Cris and Cor, Packing sand into the tubing and then bending around
>a mandrel or form works very well. Our company manufactures
>transmitters and antenna products which involves bending tubing from
>3/8 inch to as much as 3 inches or more. We flatten one end of the
>tubing as a seal, and pour sand into the tubing, while tamping down
>the tube. (For a tube that is 20 feet long, that means someone up on
>the roof pouring in the sand.) We have a device which bumps up the
>tube to ensure that the sand is packed tight. Once the tube is
>filled, the other end is flattened, and the tube is then rolled around
>the mandrel, flattened, or formed to create the coil. The hard part
>can sometimes be removing the sand.
>--- In firstname.lastname@example.org, "C. Beijersbergen"
>> An alternative method for bending tubes is as follows ( I have never
>done it, but I remember from the text books):
>> Close one end of the tube by soldering an end piece to it.
>> Fill the tube completely with fine, dry sand.
>> Compact the sand as much as possible, make sure the tube remains
>> Close the remaining end of the tube in the same manner.
>> Now the tube can be bent, it will not kink in sharp bends.
>> I remember to have seen a movie when I was a small boy about the
>fabrication of trombones, instead of sand oil was used. The closure of
>the ends of the tube was not done by soldering I suspect, but I can't
>recall those details.
>> Cor Beijersbergen
>> [Non-text portions of this message have been removed]
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