Re: HDPE mortars

In a message dated 95-10-31 19:12:35 EST, you write:

>In particular, what is the wall thickness of 6", 8", and 10" tubes?

6" is 0.32, 8" 0.33 and 10" is 0.33

>Also, would you be willing to sell just the tubes without the plugs?

Sure. Let me know how long you want them cut and how many and I can quote you
a price. 6" are $25, 8" are 50 and 10" are $85 plugged (1:1) with bolts,
poly'd and ready to go.

>How long are the mortars of the 6,8, and 10 sizes?

6" are 36", 8" are 48" and 10" are 60" (5 times the ID for internal height)


My questions are:
Would these tubes be good for coiling?
Is anyone interested in getting one or more?  If so, it appears that the vendor
will give a better price for higher quantities.


Last night I got the coil out and fired it up.  I had a new vacuum gap that
I made and thought it would work.  It has 10 1.5" Cu tubes in parallel with
a vacuum cleaner motor in a box below it to provide positive air flow across
the gap.  The gap between the tubes was set to .020.  Try as I might, I could
not get the coil to spark.  Then I tried my old pipe gap and used the exhaust
from the vacuum cleaner motor to cool it.  This worked well.
I set up the coil just within my garage and strung up some "CAUTION" tape 
in front of the garage for "crowd" control.  As people approached I would
fire up the coil.  I presented it as a hobby project, rather than some 
mad scientist gadget though.  With the cooled pipe gap, I was able to run
the coil for about 1 minute without any problems.
Some things to note:
	Earlier I had problems with sparking down the secondary.  I raised
        the secondary about 2" and this problem disappeared

	The sparks tend to emanate from one area of the toroid, so I could 
        aim the discharges.  I'm not sure if that is good or bad yet.  It
        will affect the symmetry of any time exposures though.

        I'm running at 15kV, and didn't blow my rolled cap.  Does that 
        mean that I can open the gaps up a bit more?

Some things to try for next time:
        Open up the gaps on the vacuum cleaner gap to about 0.035.
	See if the speed of the vacuum cleaner affects the quenching.
        (Scott Meyers mentioned that he didn't see much difference past 
         a low power to the vacuum motor (flame me if I'm wrong))

Later I'll try to photograph and post images of my vacuum cleaner gap.

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