Tank bottom ports
Posted: Sun Feb 19, 2012 11:37 pm
I like the idea of access ports and would also go with CNC cut plates, if
only they didn't want to charge me over $100 for shipping. Seems once they
sense a border crossing, the opportunity to make some extra money grabs
hold. So much for living on the same continent.
Seems like an academic yet simple question Ron, but how would one ensure no
leaks from the six new plates. I always try to think things through
thoroughly before cutting (learned the hard way $$$). Cutting into the
bottom of a tank really scares and newbie like me. I really like your idea,
but I do see a lot more proseal in my future. Can you share your thoughts.
Perhaps I am over thinking this again.
Roland
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ron
Shannon
Sent: Tuesday, January 24, 2012 1:06 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Re: tank bottom skin material
Aye, Drew. CAD/CNC fabrication saves a helluva lot of work, and is cheap.
To wit:
With flush covers on doublers as I've laid it out, there are 4 separate,
nominal 8" X 6" rectangles to cut per port, namely, the tank skin hole, the
cover plate, and the inside and outside of each doubler, each with four
rounded corners, for 16 rounded corners per port. With nominal 0.75"
spacing, there are 65 rivet hole pilots to layout and drill manually per
port -- 39 for the outer doubler-to-skin ring, and 26 for the
cover-to-doubler.
Multiply all those those numbers by six bays (in my case) and that's a ton
of work to do by hand, even using a template or whatever. With the machine
fab, only the 6 tank skin holes and finish rivet hole drilling need to be
done manually. If that amount of work reduction, plus the uniformity and
precision obtained isn't worth a net cost of $75-$80 for a little CNC fab
work -- after backing out the material cost you'd have either way -- I
don't know what is. (IMHO, even if you can get by with as few as two ports,
it's still a no brainer for people as lazy as me.)
Nevertheless, if Ted will do all those cuts, corners and holes just as good
for less, I'll definitely go for it. :-)
Ron
PS - Ralph, you're right, that first CAD file upload was "stinkin' " indeed
-- because I mistakenly uploaded a version without the rivet holes. All
fixed now though, with rivet holes, and virtual deodorizer to boot. ;-)
PS2 - Yes, it's [still] obvious that surface mounting takes less work and
fewer rivet holes.
On Mon, Jan 23, 2012 at 6:01 PM, Drew Dalgleish
<drewjan@cabletv.on.ca>wrote:
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only they didn't want to charge me over $100 for shipping. Seems once they
sense a border crossing, the opportunity to make some extra money grabs
hold. So much for living on the same continent.
Seems like an academic yet simple question Ron, but how would one ensure no
leaks from the six new plates. I always try to think things through
thoroughly before cutting (learned the hard way $$$). Cutting into the
bottom of a tank really scares and newbie like me. I really like your idea,
but I do see a lot more proseal in my future. Can you share your thoughts.
Perhaps I am over thinking this again.
Roland
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ron
Shannon
Sent: Tuesday, January 24, 2012 1:06 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Re: tank bottom skin material
Aye, Drew. CAD/CNC fabrication saves a helluva lot of work, and is cheap.
To wit:
With flush covers on doublers as I've laid it out, there are 4 separate,
nominal 8" X 6" rectangles to cut per port, namely, the tank skin hole, the
cover plate, and the inside and outside of each doubler, each with four
rounded corners, for 16 rounded corners per port. With nominal 0.75"
spacing, there are 65 rivet hole pilots to layout and drill manually per
port -- 39 for the outer doubler-to-skin ring, and 26 for the
cover-to-doubler.
Multiply all those those numbers by six bays (in my case) and that's a ton
of work to do by hand, even using a template or whatever. With the machine
fab, only the 6 tank skin holes and finish rivet hole drilling need to be
done manually. If that amount of work reduction, plus the uniformity and
precision obtained isn't worth a net cost of $75-$80 for a little CNC fab
work -- after backing out the material cost you'd have either way -- I
don't know what is. (IMHO, even if you can get by with as few as two ports,
it's still a no brainer for people as lazy as me.)
Nevertheless, if Ted will do all those cuts, corners and holes just as good
for less, I'll definitely go for it. :-)
Ron
PS - Ralph, you're right, that first CAD file upload was "stinkin' " indeed
-- because I mistakenly uploaded a version without the rivet holes. All
fixed now though, with rivet holes, and virtual deodorizer to boot. ;-)
PS2 - Yes, it's [still] obvious that surface mounting takes less work and
fewer rivet holes.
On Mon, Jan 23, 2012 at 6:01 PM, Drew Dalgleish
<drewjan@cabletv.on.ca>wrote:
That makes sense. I was imagining only a couple holes.
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