Hi magnet enthusiasts. I'm glad to see the interest in this simple solution to
the centuries old gnomon/glass problem. I've been using supermagnets as gnomons
now for over a year and have considerable hands-on experience. I've been using
mostly 3/32" x 7/16" magnets, one on each side of single pane glass. The gnomon
is a simple steel rod painted with rustoleum and cut at the appropriate angle.
A wood or plastic bead serves as the indicator for the 'equation of time'.
My experience with the stability of the gnomon is that if it is cut precisely
and is not too heavy that it will withstand considerable wind without moving. I
actually like the fact that it might move slightly, reminding the user of it's
presence and affording the opportunity to reestablish it's correct placement.
I've never had one fall off. Double glass is indeed a greater challenge. The
distance of separation makes a great deal of difference. Small magnets of the
above size will work, but are tenuous. Larger magnets work better.
Fortunately(?), I live in an old farmhouse with single pane windows.
The use of magnets on windows offers great artistic opportunities and
challenges. Numerous permanent printing processes on translucent velums, mylars
and waterproof papers make for exciting possibilities, especially for very
inexpensive dials that can be printed from available programs and then can be
taped directly to windows. Color and larger sizes are a bit more of a
challenge. So far, 11" x 17" is the largest I've completed. I've recently
developed a program with shading and layering of colors for hours and seasons
for just this window usage. I look forward to seeing what others come up with.
I think it's a great opportunity to help popularize sundials. A sundial for
every south, east or west facing window! sasch stephens
From: [email protected]
To: [email protected]
Subject: RE: Magnetic Gnomon (design 1)
Date: Sun, 9 Jan 2011 16:25:51 -0500
CC: [email protected]
John Carmichael raised an issue with me
directly regarding the “un-artfulness” of a tether looping out
beside the gnomon. He is correct. The simple (but additional work)
solution would be to hide it inside the mount surrounding the magnet base by
winding it around that base or it could be pushed up inside a hollow gnomon, if
the gnomon design allowed.
Larry Bohlayer
On January 9, 2011 Dave Bell
Good
thought, Larry!
Make
the tether long enough to drop the gnomon below the dial...
Dave
Sent from my iPhone
On Jan 9, 2011, at 12:21 PM, "Larry Bohlayer / Celestial Products"
<[email protected]>
wrote:
John,
Here are some thoughts on additions to
your design for the magnetic gnomon:
1.)
a
“keyed” mounting shape would help keep it from rotating out of
alignment.
2.)
a short
tether (chain or wire) to prevent loss/damage to the gnomon. One of the issues
related to using a tether would be a lose gnomon swinging in the wind and doing
damage to the glass and/or gnomon.
Larry
Larry Bohlayer
Celestial Products
608 Coral Bells Ct.
Concord, NC
28027
Office 540-338-4040, Fax 704-973-7799
Customer Service Order Line 800-235-3783
[email protected]
www.celestialproducts.com
From: [email protected]
[mailto:[email protected]] On
Behalf Of John Carmichael
Sent: Sunday, January 09, 2011
12:57 AM
To: 'Sundial List'
Subject: Magnetic Gnomon (design 1)
Since
a picture is worth a thousand words, here is a drawing of my magnetic gnomon
design that I hope to use on the new stained glass window.
To avoid
glass cracking and breakage from an impact, the gnomon is held onto the sundial
face with two magnets. One magnet is a round 1/16" thick, 1”
diameter disk located in the stained glass window. It is held in place in the
by soldered lead came.
See: www.kjmagnetics.com/proddetail.asp?prod=DX01
Next
to it is an identical brass disk with a hole in it. A small 10mm wide mounting
magnet sits in the hole. The hole in the brass disk keeps the mounting
magnet from sliding around. It is also held in place by the lead came.
See: www.kjmagnetics.com/proddetail.asp?prod=MM-D-10
A
threaded brass rod gnomon is screwed into the mounting magnet.
If
something bumps into the gnomon, it will fall off and the glass and the gnomon
won’t
get damaged.
Installation
is simple, and no nuts and bolts are required!
I
am conducting tests on this design for possible use on the stained glass
sundial that I'm making.
See:
http://www.flickr.com/photos/jlcarmichael/5338306840/
Note:
The actual gnomon will have a brass frog soldered to the brass rod. But I
left this out of the drawing to keep it simple.
John L. Carmichael
Sundial Sculptures
925 E. Foothills Dr.
Tucson AZ 85718-4716
USA
Tel: 520-6961709
Email: [email protected]
My Websites:
(business) Sundial Sculptures: http://www.sundialsculptures.com
(educational) Chinook Trail Sundial:
http://advanceassociates.com/Sundials/COSprings/
(educational) Earth & Sky Equatorial Sundial:
http://advanceassociates.com/Sundials/Earth-Sky_Dial/
(educational) My Painted Wall Sundial: http://www.advanceassociates.com/WallDial
(educational) Painted Wall Sundials:
http://advanceassociates.com/WallDial/PWS_Home.html
(educational) Stained Glass Sundials: http://www.stainedglasssundials.com
(educational) Sundial Cupolas, Towers & Turrets:
http://StainedGlassSundials.com/CupolaSundial/index.html
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