Re: Metal gnomons

[Michael Ossipoff]

What’s wrong with brass changing its color with weathering? Isn’t that part
of the appeal of brass?

On Sat, Apr 30, 2022 at 8:56 AM Dan-George Uza 
wrote:

> Hi,
>
> Iron rusts and brass changes color, but what about different metals used
> as gnomons, pros & cons?
>
> What would be the appropriate choice of material for a replica of an 18th
> century cubical multiple sundial? It should ideally come as an industrial
> sheet ready for cutting and also not stain the limestone face.
>
> I like the metal in the attached photo (Sundial Atlas CH 000247). Do you
> know what it is?
>
> Thanks,
>
> Dan Uza
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

RE: Metal gnomons

[tkreyche]

 

Dan - I forgot to add that I second John Picard’s recommendation for the 
classic Hughes and Rowe book although more recent innovations such as ceramic 
coatings are more recent. –Tom Kreyche

 

From: sundial mailto:sundial-boun...@uni-koeln.de> > On Behalf Of Dan-George Uza
Sent: Saturday, April 30, 2022 8:55 AM
To: Sundial List mailto:sundial@uni-koeln.de> >
Subject: Metal gnomons

 

Hi,

 

Iron rusts and brass changes color, but what about different metals used as 
gnomons, pros & cons?

 

What would be the appropriate choice of material for a replica of an 18th 
century cubical multiple sundial? It should ideally come as an industrial sheet 
ready for cutting and also not stain the limestone face.

 

I like the metal in the attached photo (Sundial Atlas CH 000247). Do you know 
what it is?

 

Thanks,

 

Dan Uza

---
https://lists.uni-koeln.de/mailman/listinfo/sundial

RE: Metal gnomons

[tkreyche]

Hi Dan,

 

Many choices exist depending on what kind of maintenance is expected, exposure 
to public indignities and whether you seek a natural patina. 

 

Numerous brass and bronze alloys are possible depending on price and 
availability. Flat plate can easily be cut with waterjet so you don’t need 
leaded brass. Outdoor bronze sculptures typically get an application of a wax, 
usually after a chemically applied patina, but wax must be reapplied 
periodically. Natural uncoated patinas can be unpredictable depending on local 
climate, atmosphere, handling etc. and could run onto the stone. They can be 
waxed after reaching a sought-after appearance. If you don’t like how a patina 
works out it’s easy to sand it off and start over.

 

316 stainless steel is commonly used outdoors and has added molybdenum for 
corrosion resistance and can be bead blasted for matte appearance. Probably not 
the best option for a replica. It’s very rust resistant but not rust proof. It 
does have the great advantage of being more vandal-resistant than softer metals.

 

Many metals can be high-temperature treated with tough ceramic coatings after 
machining and bead-blasting for a matt finish, such as titanium nitride which 
has a gold appearance and was once of the first to be used on drill bits, now 
there are many others. This type of custom work can get expensive although it’s 
done for special motorcycle exhausts and similar projects.

 

I would probably go with a traditional chemical patina on bronze and keep it 
waxed. Of course, many dials are eventually neglected and there is no guarantee 
anyone will continue to maintain waxing.

 

…Tom Kreyche

 

 

From: sundial  On Behalf Of Dan-George Uza
Sent: Saturday, April 30, 2022 8:55 AM
To: Sundial List 
Subject: Metal gnomons

 

Hi,

 

Iron rusts and brass changes color, but what about different metals used as 
gnomons, pros & cons?

 

What would be the appropriate choice of material for a replica of an 18th 
century cubical multiple sundial? It should ideally come as an industrial sheet 
ready for cutting and also not stain the limestone face.

 

I like the metal in the attached photo (Sundial Atlas CH 000247). Do you know 
what it is?

 

Thanks,

 

Dan Uza

---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Metal gnomons

[John Pickard]

Hi Dan,

This book may not answer your question, but it may give you some ideas 
on how to achieve patination on your gnomon.


Richard Hughes & Michael Rowe (1991) The colouring, bronzing and 
patination of metals. Thames and Hudson, London. ISBN 0500015015.


The subtitle describes the contents: "A manual for fine metalworkers, 
sculptors and designers. Cast bronze, cast brass, copper and 
copper-plate, gilding metal, sheet yellow brass, silver and silver-plate."


Cheers, John

Dr John Pickard


On 01-May-2022 01:55, Dan-George Uza wrote:

Hi,

Iron rusts and brass changes color, but what about different metals 
used as gnomons, pros & cons?


What would be the appropriate choice of material for a replica of an 
18th century cubical multiple sundial? It should ideally come as an 
industrial sheet ready for cutting and also not stain the limestone face.


I like the metal in the attached photo (Sundial Atlas CH 000247). Do 
you know what it is?


Thanks,

Dan Uza

---
https://lists.uni-koeln.de/mailman/listinfo/sundial
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: easy metal gnomons

[Ron Anthony]

Gordon,

Thanks for the info.  That's exactly what I looking for.  I have placed a
request for a minimum order.  It comes in 12' lengths so I might have some
extra to pass on to others.

++ron


-Original Message-
From: Gordon Uber <[EMAIL PROTECTED]>
To: John Carmichael <[EMAIL PROTECTED]>; Ron Anthony
<[EMAIL PROTECTED]>
Cc: sundial@rrz.uni-koeln.de 
Date: Wednesday, November 03, 1999 7:58 PM
Subject: Re: easy metal gnomons


>Youngstown Aluminum Products (Youngstown, Ohio)
><http://www.yapinc.com/contact.htm> has 1/4" quarter round listed under
>"cove," extrusion #234.
>
>Gordon
>
>
>At 06:02 PM 11/03/1999 , John Carmichael wrote:
>>Ron Anthony wrote:
>>>Anyone know where I could get quarter round in various sizes, say 1/4"
to
>
>Gordon Uber [EMAIL PROTECTED]   California, USA
>Reynen & Uber Web Design http://www.ubr.com/rey&ubr/
>Webmaster: Clocks and Time http://www.ubr.com/clocks/
>
>

Re: easy metal gnomons

[Gordon Uber]

Youngstown Aluminum Products (Youngstown, Ohio)
 has 1/4" quarter round listed under
"cove," extrusion #234.

Gordon


At 06:02 PM 11/03/1999 , John Carmichael wrote:
>Ron Anthony wrote:
>>Anyone know where I could get quarter round in various sizes, say 1/4"  to

Gordon Uber [EMAIL PROTECTED]   California, USA
Reynen & Uber Web Design http://www.ubr.com/rey&ubr/
Webmaster: Clocks and Time http://www.ubr.com/clocks/

Re: easy metal gnomons

[John Carmichael]

Ron Anthony wrote:
>
>My gnomons are often made from 1/32" of aluminum.  For reinforcement I
>attach smaller triangles on either side of the gnomon. I too have used two
>90 degree angle pieces to mount gnomons, but have never been satisfied with
>the look.  I have been looking for brass or alumimum that is shape as a
>quarter round. (You know, like wood moulding).  I think that would provide a
>stronger and better looking attachment.
>
>Anyone know where I could get quarter round in various sizes, say 1/4"  to
>1/2"?
>
>I have found a source for half ovals.  I haven't tried it yet but I was
>thinking I could cut a slot in the half oval to mount the gnomon.  Of
>course, a square or rectangle bar could also be used, but in my mind's eye I
>prefer the curved shapes.

Hi Ron:

I have never seen quarter round pieces of any metal anywhere, but I think
you could very easily make your own quarter round by sanding down one long
edge of a square rod.  The small Dremmel or Delta belt sander mentioned
earlier would work fine.  Square rods of all sizes and metals are readily
available.

John Carmichael

RE: easy metal gnomons

[Tony Moss]

Anthony Cordasco replied

snip..

>Tony. You mention that the rate of cooling is unimportant but if I
>recall correctly from my silversmithing days at the Jewish Museum in N.Y.C.,
>brass was the one metal which seemed to be softer when we dipped it in water
>while it was hot.  This is not the case with copper, silver, or gold. 
>

Anthony

I'm ever ready to yield to hard experience!  Please correct my earlier 
statement to read "...but brass may seem softer when quenched!"*

Tony M.

*  A good subject for a 1st Year metallurgical seminar perhaps?  Come on 
you guys... give us some numerical evidence!

RE: easy metal gnomons

[Cordasco, Anthony (NJ Data Services)]

Sometimes in working with iron we counter bend the metal before forging it
and as you forge you are actually straightening the metal.  
Also, with a soft material like brass you can anneal after you hammer the
edge over and then straighten it out by hand or mallet.  You should always
keep in mind that you are work hardening any section you hammer. 
This may all seem tricky but if you are working with short lengths of metal
and smaller diameters it's not really that bad and a little trial and error
will go a long way. 
 
Anthony 
p.s. Tony. You mention that the rate of cooling is unimportant but if I
recall correctly from my silversmithing days at the Jewish Museum in N.Y.C.,
brass was the one metal which seemed to be softer when we dipped it in water
while it was hot.  This is not the case with copper, silver, or gold. 

-Original Message-
From: Tony Moss [mailto:[EMAIL PROTECTED]
Sent: Wednesday, November 03, 1999 3:02 PM
To: Cordasco, Anthony (NJ Data Services); 'sundial@rrz.uni-koeln.de'
Subject: RE: easy metal gnomons


Anthony Cardasco contributed:

>I am assuming you don't have access to a bandsaw, lathe or milling machine.
>One "by hand" method you could use is to take a square bar of brass or
>aluminum and file off one corner to make a 45 degree chamfer 

A word of caution when removing large amounts from one edge of a 
hard-drawn metal bar or even sawing a gnomon out of thick plate material. 
 The outer skin of the metal will have enormous stresses contained within 
it resulting from being drawn through shaped dies.  Because these 
stresses are all balanced out the uncut bar stays straight.  Remove half 
a diameter or cut out your gnomon shape leaving an existing straight edge 
as the style - and then wonder why it has gone banana shaped?

There are two ways round this:

1.  Anticipate that the straight edge will bend - usually away from the 
cut line - and allow some extra for filing/machining it straight again.

2.  'Anneal' the bar before cutting to allow all those internal stresses 
to relax.  For brass/copper/bronze this involves heating to a visible red 
then allowing the metal to cool.  The rate of cooling is unimportant.  
Many people 'pickle' the hot metal in 10% sulphuric acid at this stage to 
remove oxide scale.  I prefer to use a big stoneware jar of ordinary malt 
vinegar.  The fumes and the liquid are far less hazardous but the process 
is equally effective.  Small parts can be retrieved by hand if dropped 
into the solution.

Aluminium alloys can be annealed by rubbing ordinary soap on the metal 
and then heating evenly until it turns black.

Annealing also makes the metal soft and bendable without cracking so if 
you want it left in a hard condition it's method 1. for you.

Best Wishes

Tony Moss.

RE: easy metal gnomons

[Tony Moss]

Anthony Cardasco contributed:

>I am assuming you don't have access to a bandsaw, lathe or milling machine.
>One "by hand" method you could use is to take a square bar of brass or
>aluminum and file off one corner to make a 45 degree chamfer 

A word of caution when removing large amounts from one edge of a 
hard-drawn metal bar or even sawing a gnomon out of thick plate material. 
 The outer skin of the metal will have enormous stresses contained within 
it resulting from being drawn through shaped dies.  Because these 
stresses are all balanced out the uncut bar stays straight.  Remove half 
a diameter or cut out your gnomon shape leaving an existing straight edge 
as the style - and then wonder why it has gone banana shaped?

There are two ways round this:

1.  Anticipate that the straight edge will bend - usually away from the 
cut line - and allow some extra for filing/machining it straight again.

2.  'Anneal' the bar before cutting to allow all those internal stresses 
to relax.  For brass/copper/bronze this involves heating to a visible red 
then allowing the metal to cool.  The rate of cooling is unimportant.  
Many people 'pickle' the hot metal in 10% sulphuric acid at this stage to 
remove oxide scale.  I prefer to use a big stoneware jar of ordinary malt 
vinegar.  The fumes and the liquid are far less hazardous but the process 
is equally effective.  Small parts can be retrieved by hand if dropped 
into the solution.

Aluminium alloys can be annealed by rubbing ordinary soap on the metal 
and then heating evenly until it turns black.

Annealing also makes the metal soft and bendable without cracking so if 
you want it left in a hard condition it's method 1. for you.

Best Wishes

Tony Moss.

RE: easy metal gnomons

[Cordasco, Anthony (NJ Data Services)]

I have been looking for brass or alumimum that is shape as a
quarter round. (You know, like wood moulding).  I think that would provide a
stronger and better looking attachment.
Anyone know where I could get quarter round in various sizes, say 1/4"  to
1/2"?
++ron
--
Ron:
I am assuming you don't have access to a bandsaw, lathe or milling machine.
One "by hand" method you could use is to take a square bar of brass or
aluminum and file off one corner to make a 45 degree chamfer (you can draw
file this very quickly). Hammer the chamfered edge to a curved shape. If you
are unsure of your hammer control you can place the square bar in a length
of angle iron(to keep the bottom and side edges sharp).  Use a nicely
polished hammer face and preferably one with a convex surface. The more you
plannish it the smaller will be the hammer marks but they can be quite nice
if left in. Buff with something like tripoli compound. That should give you
a very nice hand worked piece of 1/4 round stock. 
There is another method which uses a drawplate but that is only good for
smaller stock.
Regards,
Anthony

Re: easy metal gnomons

[Ron Anthony]

John,

>Michael Koblic wrote:
>>1) How do you attach a 1/16" thick gnomon vertically to a dial plate?
>>Presumably you must bend the gnomon at the base somehow first.
>
>Although my string gnomons are quite different, I have made traditional
>triangular and rectangular gnomons for other dials.  I attached these
>gnomons to the dial plate by sandwiching the gnomon in-between two 90
degree
>angle pieces and bolting it to them with two bolts. This give an upside
down
>"T" shape when viewed on edge.  The flat bottom of the angled pieces can
>then be easily bolted to the dial face.

My gnomons are often made from 1/32" of aluminum.  For reinforcement I
attach smaller triangles on either side of the gnomon. I too have used two
90 degree angle pieces to mount gnomons, but have never been satisfied with
the look.  I have been looking for brass or alumimum that is shape as a
quarter round. (You know, like wood moulding).  I think that would provide a
stronger and better looking attachment.

Anyone know where I could get quarter round in various sizes, say 1/4"  to
1/2"?

I have found a source for half ovals.  I haven't tried it yet but I was
thinking I could cut a slot in the half oval to mount the gnomon.  Of
course, a square or rectangle bar could also be used, but in my mind's eye I
prefer the curved shapes.


++ron

Re: easy metal gnomons

[John Carmichael]

Hello dial makers:

As soon as I sent my last post on easy-to-make metal gnomons, I thought of
some additional comments. I'll also try to answer questions and comments by
Michael Koblic and Anthony Cordasco.

Anthony's three suggestions are all good. He said to use rubber cement
instead of white glue, to use a metal punch instead of a nail, and to use a
metal backing when drilling to avoid burrs.  The only things I might add are
that if you do get burrs around the drill hole, the same Dremmel cutoff disk
will remove them.  Also, you should use the high speed setting on your
Dremmel when cutting and you should wear a face mask and protective glasses! 

Michael Koblic wrote:
>1) How do you attach a 1/16" thick gnomon vertically to a dial plate?
>Presumably you must bend the gnomon at the base somehow first.

Although my string gnomons are quite different, I have made traditional
triangular and rectangular gnomons for other dials.  I attached these
gnomons to the dial plate by sandwiching the gnomon in-between two 90 degree
angle pieces and bolting it to them with two bolts. This give an upside down
"T" shape when viewed on edge.  The flat bottom of the angled pieces can
then be easily bolted to the dial face.

>
>3) I like to do the final shaping and smoothing of the gnomon on a belt
>sander using 120 grit paper (the finest I have been able to get locally - I
>have seen knife-making supply shops advertise finer grit in the US). The
>straight edges are great and one can get he gnomon angles just right. I then
>buff away the 120 grit marks using a felt wheel and an aggressive buffing
>compound on my bench ginder.

Good point.  I also use a belt sander with very good results.  Both Dremmel
and Delta make small very inexpensive belt sanders that also have built-in
5" disk sanders.
>
>4) For marking out holes for drill bits I suggest using a proper marker
>punch - nails tend to have rather unpredictably irregular points.

Yea, I use a punch also.  The only reason I suggested a nail was because I
didn't know if everyone knew what a punch was and nails work ok when I lose
my punch, which happens frequently!

This method of metal cutting can make an inexpensive, respectable and sturdy
gnomon, but if you want a REALLY nice professional metal gnomon, buy one
from Tony Moss.

happy dialing,

John Carmichael
925 E. Foothills Dr.
Tucson Az 85718
USA
tel:  520-6961709
http://www.azstarnet.com/~pappas

Re: easy metal gnomons

[Michael Koblic]

At 08:19 AM 11/2/99 -0700, you wrote:
>Hello all:
>
>Although metal working is not my forte, I do use metal (brass) to make the
>gnomons for my stone sundials.  I have found that the common Dremmel
>moto-tool when fitted with a Dremmel 1.5" black composite cutoff disk and
>arbor, will easily cut metal.  These cutoff disks will be found in the
>Dremmel department of your local hardware store.  They can be used to make
>straight cuts and also are suitable for some types of engraving.
>
>If you buy a sheet of metal (brass, copper, aluminum, or steel), you can
>easily make your own gnomons.  I use 14 guage (1/16" thick) sheets, but this
>method will cut even thicker pieces.  I suggest that you use the perfectly
>straight foundry-cut edge of the sheet as the style side of the gnomon.
>First draw the lines to be cut with a fine point "Sharpee" pen or glue a
>paper drawing of the desired cuts onto the metal with water soluble white
>glue.  After cutting the other sides, use sandpaper with a block of wood to
>smooth the sides that you have cut with your Dremmel.  Holes for attaching
>the gnomon to your dial plate can then be drilled through the metal with a
>hand-held drill with metal bits. (Before drilling, make a little indentation
>in the metal with the point of a nail and hammer to serve as a guide for the
>bit so that it doesn't wander).
>
>Besides cutting metal sheets to make traditional triangular gnomons, your
>Dremmel can also cut rods for vertical or perpendicular gnomons.
>
>I Hope this simple technique will be of use to some of you.
>
>John Carmichael
>925 E. Foothills Dr.
>Tucson Az 85718
>USA
>tel: 520-696-1709
>website:  http://www.azstarnet.com/~pappas
>
>

Few questions and points:

1) How do you attach a 1/16" thick gnomon vertically to a dial plate?
Presumably you must bend the gnomon at the base somehow first.

2) I use 1/8" brass for both the dial plate and the gnomon. I used to drill
1/16" holes into the bottom of the gnomon (there is just enough space) and
corresponding holes in the dial plate. Then I used 1/16" brass brazing rods
cut to small lengths as pins to hold the whole thing together. Worked
surprisingly well. More recently I made somewhat fancier gnomon with bits of
1/8" brass and soldered it to a 1/8" base with holes in it to screw the
whole assembly to the dial plate. On the whole, I was more pleased with the
latter.

3) I like to do the final shaping and smoothing of the gnomon on a belt
sander using 120 grit paper (the finest I have been able to get locally - I
have seen knife-making supply shops advertise finer grit in the US). The
straight edges are great and one can get he gnomon angles just right. I then
buff away the 120 grit marks using a felt wheel and an aggressive buffing
compound on my bench ginder.

4) For marking out holes for drill bits I suggest using a proper marker
punch - nails tend to have rather unpredictably irregular points.

Mike Koblic,
Quesnel BC

RE: easy metal gnomons

[Cordasco, Anthony (NJ Data Services)]

Just a few suggestions to add to John's description:
* Instead of a nail use a center punch.
* Instead of white glue use rubber cement.
* When drilling holes use a piece of brass or copper as a backing plate and
you will avoid a metal burr.

For making intricate cuts I would suggest a jewelers saw frame. 

Regards,
Anthony 

-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Tuesday, November 02, 1999 10:19 AM
To: sundial@rrz.uni-koeln.de
Subject: easy metal gnomons


Hello all:

Although metal working is not my forte, I do use metal (brass) to make the
gnomons for my stone sundials.  I have found that the common Dremmel
moto-tool when fitted with a Dremmel 1.5" black composite cutoff disk and
arbor, will easily cut metal.  These cutoff disks will be found in the
Dremmel department of your local hardware store.  They can be used to make
straight cuts and also are suitable for some types of engraving.

If you buy a sheet of metal (brass, copper, aluminum, or steel), you can
easily make your own gnomons.  I use 14 guage (1/16" thick) sheets, but this
method will cut even thicker pieces.  I suggest that you use the perfectly
straight foundry-cut edge of the sheet as the style side of the gnomon.
First draw the lines to be cut with a fine point "Sharpee" pen or glue a
paper drawing of the desired cuts onto the metal with water soluble white
glue.  After cutting the other sides, use sandpaper with a block of wood to
smooth the sides that you have cut with your Dremmel.  Holes for attaching
the gnomon to your dial plate can then be drilled through the metal with a
hand-held drill with metal bits. (Before drilling, make a little indentation
in the metal with the point of a nail and hammer to serve as a guide for the
bit so that it doesn't wander).

Besides cutting metal sheets to make traditional triangular gnomons, your
Dremmel can also cut rods for vertical or perpendicular gnomons.

I Hope this simple technique will be of use to some of you.

John Carmichael
925 E. Foothills Dr.
Tucson Az 85718
USA
tel: 520-696-1709
website:  http://www.azstarnet.com/~pappas

easy metal gnomons

[John Carmichael]

Hello all:

Although metal working is not my forte, I do use metal (brass) to make the
gnomons for my stone sundials.  I have found that the common Dremmel
moto-tool when fitted with a Dremmel 1.5" black composite cutoff disk and
arbor, will easily cut metal.  These cutoff disks will be found in the
Dremmel department of your local hardware store.  They can be used to make
straight cuts and also are suitable for some types of engraving.

If you buy a sheet of metal (brass, copper, aluminum, or steel), you can
easily make your own gnomons.  I use 14 guage (1/16" thick) sheets, but this
method will cut even thicker pieces.  I suggest that you use the perfectly
straight foundry-cut edge of the sheet as the style side of the gnomon.
First draw the lines to be cut with a fine point "Sharpee" pen or glue a
paper drawing of the desired cuts onto the metal with water soluble white
glue.  After cutting the other sides, use sandpaper with a block of wood to
smooth the sides that you have cut with your Dremmel.  Holes for attaching
the gnomon to your dial plate can then be drilled through the metal with a
hand-held drill with metal bits. (Before drilling, make a little indentation
in the metal with the point of a nail and hammer to serve as a guide for the
bit so that it doesn't wander).

Besides cutting metal sheets to make traditional triangular gnomons, your
Dremmel can also cut rods for vertical or perpendicular gnomons.

I Hope this simple technique will be of use to some of you.

John Carmichael
925 E. Foothills Dr.
Tucson Az 85718
USA
tel: 520-696-1709
website:  http://www.azstarnet.com/~pappas