On Fri, 26 Dec 2014 21:56:08 -0800, Gunner Asch wrote:

Just finished sorting out my film camera collection and found 7
different Minolta compatible lenses..and no Minolta SLR to fit them to.
Would have sworn I had an SRT 202 or 101...cant find it.
So would like to swap/trade/buy (cheap) a body that these lenses will
work on. I think the last model that they will fit is the XM-700


The 101 had a common flaw that the others may also share. The cement
joining two parts of the prism assembly was IIRC canada balsam and with
time it changed (crystallized?) resulting in the meter not reading
correctly (mine was way off, several stops). It's a bit fiddly to take
apart and fix, the hard part is deciding what cement to use/where to get
it.

In article , unk wrote:

On Fri, 26 Dec 2014 21:56:08 -0800, Gunner Asch wrote:

Just finished sorting out my film camera collection and found 7
different Minolta compatible lenses..and no Minolta SLR to fit them to.
Would have sworn I had an SRT 202 or 101...cant find it.
So would like to swap/trade/buy (cheap) a body that these lenses will
work on. I think the last model that they will fit is the XM-700


The 101 had a common flaw that the others may also share. The cement
joining two parts of the prism assembly was IIRC canada balsam and with
time it changed (crystallized?) resulting in the meter not reading
correctly (mine was way off, several stops). It's a bit fiddly to take
apart and fix, the hard part is deciding what cement to use/where to get
it.

I have no opinion on Minolta repair, but the standard optical cements
for prisms (replacing Canada Balsam) are those made by Norland, such as
NOA60.

https://www.norlandprod.com/adhesiveindex2.html

Don't be discouraged by the UV cure requirement. The standard
low-volume approach is to park the assembly in sunlight, arranged such
that the sunlight reaches all glue surfaces. In a few hours, it will
be cured.

The big issue will be making a fixture to hold the prism parts in the
correct alignment while the adhesive cures. But there is no hurry
under incandescent light - not enough UV to cause curing, so one can
take as long as needed.

Joe Gwinn

On Sat, 27 Dec 2014 09:36:54 -0500, Joe Gwinn
wrote:

In article , unk wrote:

On Fri, 26 Dec 2014 21:56:08 -0800, Gunner Asch wrote:

Just finished sorting out my film camera collection and found 7
different Minolta compatible lenses..and no Minolta SLR to fit them to.
Would have sworn I had an SRT 202 or 101...cant find it.
So would like to swap/trade/buy (cheap) a body that these lenses will
work on. I think the last model that they will fit is the XM-700


The 101 had a common flaw that the others may also share. The cement
joining two parts of the prism assembly was IIRC canada balsam and with
time it changed (crystallized?) resulting in the meter not reading
correctly (mine was way off, several stops). It's a bit fiddly to take
apart and fix, the hard part is deciding what cement to use/where to get
it.

I have no opinion on Minolta repair, but the standard optical cements
for prisms (replacing Canada Balsam) are those made by Norland, such as
NOA60.

https://www.norlandprod.com/adhesiveindex2.html

Don't be discouraged by the UV cure requirement. The standard
low-volume approach is to park the assembly in sunlight, arranged such
that the sunlight reaches all glue surfaces. In a few hours, it will
be cured.

Inside an unfocused solar oven, y'mean?

Don't forget that extremely cheap UV lights are available now, in
several popular UV wavelengths. I bought a 9 LED (385-400nm) via eBay
for $1.80 with free delivery. It's good for checking money, detecting
leaks and salmonella, and for urine detection in client homes, etc. (I
don't do pets, children, or other slaves.) I wonder how well it would
do with UV-curing glue.

365nm resin curing lights are quite a bit more, $18.


The big issue will be making a fixture to hold the prism parts in the
correct alignment while the adhesive cures. But there is no hurry
under incandescent light - not enough UV to cause curing, so one can
take as long as needed.

Abrading/removing the old adhesive can be tricky, I'll bet.
Hopefully, the parts are regularly shaped, with no overhangs. g

--
Learn the art of patience. Apply discipline to your thoughts when they
become anxious over the outcome of a goal. Impatience breeds anxiety,
fear, discouragement and failure. Patience creates confidence, de-
cisiveness, and a rational outlook, which eventually leads to success.
--Brian Adams

On Sat, 27 Dec 2014 14:03:08 +0000 (UTC), unk wrote:

On Fri, 26 Dec 2014 21:56:08 -0800, Gunner Asch wrote:

Just finished sorting out my film camera collection and found 7
different Minolta compatible lenses..and no Minolta SLR to fit them to.
Would have sworn I had an SRT 202 or 101...cant find it.
So would like to swap/trade/buy (cheap) a body that these lenses will
work on. I think the last model that they will fit is the XM-700


The 101 had a common flaw that the others may also share. The cement
joining two parts of the prism assembly was IIRC canada balsam and with
time it changed (crystallized?) resulting in the meter not reading
correctly (mine was way off, several stops). It's a bit fiddly to take
apart and fix, the hard part is deciding what cement to use/where to get
it.

Thanks! for that bit of info. Was the problem still with the later
202 series?


"At the core of liberalism is the spoiled child,
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosophy of sniveling brats."
PJ O'Rourke

In article , Larry Jaques
wrote:

On Sat, 27 Dec 2014 09:36:54 -0500, Joe Gwinn
wrote:

In article , unk wrote:

On Fri, 26 Dec 2014 21:56:08 -0800, Gunner Asch wrote:

Just finished sorting out my film camera collection and found 7
different Minolta compatible lenses..and no Minolta SLR to fit them to.
Would have sworn I had an SRT 202 or 101...cant find it.
So would like to swap/trade/buy (cheap) a body that these lenses will
work on. I think the last model that they will fit is the XM-700

The 101 had a common flaw that the others may also share. The cement
joining two parts of the prism assembly was IIRC canada balsam and with
time it changed (crystallized?) resulting in the meter not reading
correctly (mine was way off, several stops). It's a bit fiddly to take
apart and fix, the hard part is deciding what cement to use/where to get
it.

I have no opinion on Minolta repair, but the standard optical cements
for prisms (replacing Canada Balsam) are those made by Norland, such as
NOA 60.

https://www.norlandprod.com/adhesiveindex2.html

Don't be discouraged by the UV cure requirement. The standard
low-volume approach is to park the assembly in sunlight, arranged such
that the sunlight reaches all glue surfaces. In a few hours, it will
be cured.

Inside an unfocused solar oven, y'mean?

Nope. Window sill. I've done it, in the Boston area. Norland does
mention this method in their data sheets, so this is a mfgr approved
method.


Don't forget that extremely cheap UV lights are available now, in
several popular UV wavelengths. I bought a 9 LED (385-400nm) via eBay
for $1.80 with free delivery. It's good for checking money, detecting
leaks and salmonella, and for urine detection in client homes, etc. (I
don't do pets, children, or other slaves.) I wonder how well it would
do with UV-curing glue.

Probably not all that well, if I recall. Wavelength too long - "UV"
is a wide band. The band is 340 to 400 nanometers, and I bet that the
shorter wavelengths cause faster curing, all else being equal, because
shorter wavelength photons carry more energy per photon.


365nm resin curing lights are quite a bit more, $18.

Yep, if the power output of the $18 units is sufficient. Norland does
specify the optical band and total optical energy required.


The big issue will be making a fixture to hold the prism parts in the
correct alignment while the adhesive cures. But there is no hurry
under incandescent light - not enough UV to cause curing, so one can
take as long as needed.

Abrading/removing the old adhesive can be tricky, I'll bet.
Hopefully, the parts are regularly shaped, with no overhangs. g

Abrade? Do not abrade *anything* off of an optical surface!

Methylene chloride paint stripper, then acetone (to get the stripper
off). Or, more commonly, soak overnight in acetone. Canada balsam
isn't all that difficult to remove. Old optical manufacturing books
tell all about it.

Joe Gwinn

On Sat, 27 Dec 2014 17:14:51 -0500, Joe Gwinn
wrote:

In article , Larry Jaques
wrote:

On Sat, 27 Dec 2014 09:36:54 -0500, Joe Gwinn
wrote:

In article , unk wrote:

On Fri, 26 Dec 2014 21:56:08 -0800, Gunner Asch wrote:

Just finished sorting out my film camera collection and found 7
different Minolta compatible lenses..and no Minolta SLR to fit them to.
Would have sworn I had an SRT 202 or 101...cant find it.
So would like to swap/trade/buy (cheap) a body that these lenses will
work on. I think the last model that they will fit is the XM-700

The 101 had a common flaw that the others may also share. The cement
joining two parts of the prism assembly was IIRC canada balsam and with
time it changed (crystallized?) resulting in the meter not reading
correctly (mine was way off, several stops). It's a bit fiddly to take
apart and fix, the hard part is deciding what cement to use/where to get
it.

I have no opinion on Minolta repair, but the standard optical cements
for prisms (replacing Canada Balsam) are those made by Norland, such as
NOA 60.

https://www.norlandprod.com/adhesiveindex2.html

Don't be discouraged by the UV cure requirement. The standard
low-volume approach is to park the assembly in sunlight, arranged such
that the sunlight reaches all glue surfaces. In a few hours, it will
be cured.

Inside an unfocused solar oven, y'mean?

Nope. Window sill. I've done it, in the Boston area. Norland does
mention this method in their data sheets, so this is a mfgr approved
method.

Amazing!


Don't forget that extremely cheap UV lights are available now, in
several popular UV wavelengths. I bought a 9 LED (385-400nm) via eBay
for $1.80 with free delivery. It's good for checking money, detecting
leaks and salmonella, and for urine detection in client homes, etc. (I
don't do pets, children, or other slaves.) I wonder how well it would
do with UV-curing glue.

Probably not all that well, if I recall. Wavelength too long - "UV"
is a wide band. The band is 340 to 400 nanometers, and I bet that the
shorter wavelengths cause faster curing, all else being equal, because
shorter wavelength photons carry more energy per photon.

I read a couple adhesive mfgr pages yesterday and they stated that
anything between 200-400um would work for their goos.


365nm resin curing lights are quite a bit more, $18.

Yep, if the power output of the $18 units is sufficient. Norland does
specify the optical band and total optical energy required.

I don't think I checked that, but would assume (kaff,kaff) that
purpose-built UV flashlights would have more than the windowsill.
I didn't find density info on any UV flashlights. sigh


The big issue will be making a fixture to hold the prism parts in the
correct alignment while the adhesive cures. But there is no hurry
under incandescent light - not enough UV to cause curing, so one can
take as long as needed.

Abrading/removing the old adhesive can be tricky, I'll bet.
Hopefully, the parts are regularly shaped, with no overhangs. g

Abrade? Do not abrade *anything* off of an optical surface!

OK. I thought the glue would melt them into one piece so it wouldn't
matter.


Methylene chloride paint stripper, then acetone (to get the stripper
off). Or, more commonly, soak overnight in acetone. Canada balsam
isn't all that difficult to remove. Old optical manufacturing books
tell all about it.

I haven't worked with it yet. (rather than saying "never")

--
Learn the art of patience. Apply discipline to your thoughts when they
become anxious over the outcome of a goal. Impatience breeds anxiety,
fear, discouragement and failure. Patience creates confidence, de-
cisiveness, and a rational outlook, which eventually leads to success.
--Brian Adams

In article , Larry Jaques
wrote:

On Sat, 27 Dec 2014 17:14:51 -0500, Joe Gwinn
wrote:

In article , Larry Jaques
wrote:

On Sat, 27 Dec 2014 09:36:54 -0500, Joe Gwinn
wrote:

In article , unk wrote:

On Fri, 26 Dec 2014 21:56:08 -0800, Gunner Asch wrote:

Just finished sorting out my film camera collection and found 7
different Minolta compatible lenses..and no Minolta SLR to fit them
to.
Would have sworn I had an SRT 202 or 101...cant find it.
So would like to swap/trade/buy (cheap) a body that these lenses will
work on. I think the last model that they will fit is the XM-700

The 101 had a common flaw that the others may also share. The cement
joining two parts of the prism assembly was IIRC canada balsam and with
time it changed (crystallized?) resulting in the meter not reading
correctly (mine was way off, several stops). It's a bit fiddly to take
apart and fix, the hard part is deciding what cement to use/where to
get
it.

I have no opinion on Minolta repair, but the standard optical cements
for prisms (replacing Canada Balsam) are those made by Norland, such as
NOA 60.

https://www.norlandprod.com/adhesiveindex2.html

Don't be discouraged by the UV cure requirement. The standard
low-volume approach is to park the assembly in sunlight, arranged such
that the sunlight reaches all glue surfaces. In a few hours, it will
be cured.

Inside an unfocused solar oven, y'mean?

Nope. Window sill. I've done it, in the Boston area. Norland does
mention this method in their data sheets, so this is a mfgr approved
method.

Amazing!


Don't forget that extremely cheap UV lights are available now, in
several popular UV wavelengths. I bought a 9 LED (385-400nm) via eBay
for $1.80 with free delivery. It's good for checking money, detecting
leaks and salmonella, and for urine detection in client homes, etc. (I
don't do pets, children, or other slaves.) I wonder how well it would
do with UV-curing glue.

Probably not all that well, if I recall. Wavelength too long - "UV"
is a wide band. The band is 340 to 400 nanometers, and I bet that the
shorter wavelengths cause faster curing, all else being equal, because
shorter wavelength photons carry more energy per photon.

I read a couple adhesive mfgr pages yesterday and they stated that
anything between 200-400um would work for their goos.

That seems to be the range. Probably, the patents ran down.


365nm resin curing lights are quite a bit more, $18.

Yep, if the power output of the $18 units is sufficient. Norland does
specify the optical band and total optical energy required.

I don't think I checked that, but would assume (kaff,kaff) that
purpose-built UV flashlights would have more than the windowsill.
I didn't find density info on any UV flashlights. sigh

If UV optical power is unspecified, it's probably insufficient.


The big issue will be making a fixture to hold the prism parts in the
correct alignment while the adhesive cures. But there is no hurry
under incandescent light - not enough UV to cause curing, so one can
take as long as needed.

Abrading/removing the old adhesive can be tricky, I'll bet.
Hopefully, the parts are regularly shaped, with no overhangs. g

Abrade? Do not abrade *anything* off of an optical surface!

OK. I thought the glue would melt them into one piece so it wouldn't
matter.

The pieces are glass, and the glue is organic. If the pieces were
organic, then welding would be likely.


Methylene chloride paint stripper, then acetone (to get the stripper
off). Or, more commonly, soak overnight in acetone. Canada balsam
isn't all that difficult to remove. Old optical manufacturing books
tell all about it.

I haven't worked with it yet. (rather than saying "never")

Norland has an app note on how to remove their cement. This method
(which involves soaking in methylene chloride) seems adequate for
Canada balsam.

Joe Gwinn

On Sun, 28 Dec 2014 22:20:45 -0500, Joe Gwinn
wrote:

In article , Larry Jaques
wrote:
I don't think I checked that, but would assume (kaff,kaff) that
purpose-built UV flashlights would have more than the windowsill.
I didn't find density info on any UV flashlights. sigh

If UV optical power is unspecified, it's probably insufficient.

I found an article saying that sunlight averages 4.5-6.5mw/cm3.


The big issue will be making a fixture to hold the prism parts in the
correct alignment while the adhesive cures. But there is no hurry
under incandescent light - not enough UV to cause curing, so one can
take as long as needed.

Abrading/removing the old adhesive can be tricky, I'll bet.
Hopefully, the parts are regularly shaped, with no overhangs. g

Abrade? Do not abrade *anything* off of an optical surface!

OK. I thought the glue would melt them into one piece so it wouldn't
matter.

The pieces are glass, and the glue is organic. If the pieces were
organic, then welding would be likely.

I'm thinking of items at the far lower end of the spectrum, as it
were, than you, it appears. g


Methylene chloride paint stripper, then acetone (to get the stripper
off). Or, more commonly, soak overnight in acetone. Canada balsam
isn't all that difficult to remove. Old optical manufacturing books
tell all about it.

I haven't worked with it yet. (rather than saying "never")

Norland has an app note on how to remove their cement. This method
(which involves soaking in methylene chloride) seems adequate for
Canada balsam.

That's _much_ easier than sanding. giggle

--
Learn the art of patience. Apply discipline to your thoughts when they
become anxious over the outcome of a goal. Impatience breeds anxiety,
fear, discouragement and failure. Patience creates confidence, de-
cisiveness, and a rational outlook, which eventually leads to success.
--Brian Adams

In article , Larry Jaques
wrote:

On Sun, 28 Dec 2014 22:20:45 -0500, Joe Gwinn
wrote:

In article , Larry Jaques
wrote:
I don't think I checked that, but would assume (kaff,kaff) that
purpose-built UV flashlights would have more than the windowsill.
I didn't find density info on any UV flashlights. sigh

If UV optical power is unspecified, it's probably insufficient.

I found an article saying that sunlight averages 4.5-6.5mw/cm3.

In the relevant UV band? That's plenty, so long as one is in no hurry.


The big issue will be making a fixture to hold the prism parts in the
correct alignment while the adhesive cures. But there is no hurry
under incandescent light - not enough UV to cause curing, so one can
take as long as needed.

Abrading/removing the old adhesive can be tricky, I'll bet.
Hopefully, the parts are regularly shaped, with no overhangs. g

Abrade? Do not abrade *anything* off of an optical surface!

OK. I thought the glue would melt them into one piece so it wouldn't
matter.

The pieces are glass, and the glue is organic. If the pieces were
organic, then welding would be likely.

I'm thinking of items at the far lower end of the spectrum, as it
were, than you, it appears. g

This was for a Minolta SLR camera, as I recall. These used pentaprisms
made of glass.

I don't think that any pentaprisms were made of plastic, because the
optical quality was not sufficient.

Some brands used a nest of first-surface mirrors, but these were glass
as well. There was some debate about which was best: mirrors were
lighter, but far harder to align and keep aligned, than solid glass.
Solid glass eventually won.


Methylene chloride paint stripper, then acetone (to get the stripper
off). Or, more commonly, soak overnight in acetone. Canada balsam
isn't all that difficult to remove. Old optical manufacturing books
tell all about it.

I haven't worked with it yet. (rather than saying "never")

Norland has an app note on how to remove their cement. This method
(which involves soaking in methylene chloride) seems adequate for
Canada balsam.

That's _much_ easier than sanding. giggle

Yes, and much less nerve wracking.


There is much information available on how to cement optical
assemblies. One should practice on some window glass first. And be
prepared to de-cement your first attempt at the real thing. This does
not damage the glass, so the main worry is the time taken. As
previously mentioned, some kind of alignment fixture is needed, and
mis-alignment is a major cause of rework.

Here is one such source:

http://web.archive.org/web/200702201...iasum.com/summ
ers/optical/cements/manual/manual.html


Joe Gwinn