PCB Photoresist Chemical

A

Animesh Maurya

Guest
Hi everybody,

Sorry, although this is not anyhow related with electronics,
but I think you people can me.

Can anybody exactly mention which chemical is used to photoresist PCB.

Thank you,

Animesh Maurya
 
Animesh Maurya wrote:
Hi everybody,

Sorry, although this is not anyhow related with electronics,
but I think you people can me.

Can anybody exactly mention which chemical is used to photoresist PCB.

Thank you,

Animesh Maurya
In the "good old daze" of hand-layouts ("taping"), Kodak Photo Resist
(KPR) was commonly used, along with KMER.
However, an el-cheapo way is to use egg-white sensitized with
Potassiun DiChromate.
Exposure to UV in either case polymerized the material, allowing the
solvent to wash away the un-exposed material.
For the sensitized egg-white, warm water is the developer, and one can
do some careful baking to achieve a more robust covering.
Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).
Ordinary water is bad enough on mountains!
 
I read in sci.electronics.design that Robert Baer
<robertbaer@earthlink.net> wrote (in <402B3A5B.95ED89E2@earthlink.net>)
about 'PCB Photoresist Chemical', on Thu, 12 Feb 2004:

water becomes more corrosive as the
purity increases (no joke).
When do you collect your Nobel Prize for that discovery? (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
Robert Baer wrote:
Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).
Corrosive to what ?, sodium metal?
 
Adam S. wrote:
Robert Baer wrote:

Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).


Corrosive to what ?, sodium metal?
Lead springs to mind - lead pipes are more dangerous with soft water.

Leon
--
Leon Heller, G1HSM
Email: aqzf13@dsl.pipex.com
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html
 
"Leon Heller" <aqzf13@dsl.pipex.com> wrote in message
news:402b6198$0$34$cc9e4d1f@news.dial.pipex.com...
Adam S. wrote:


Robert Baer wrote:

Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).


Corrosive to what ?, sodium metal?

Lead springs to mind - lead pipes are more dangerous with soft water.
But traces of chloride ion make water much more corrosive on damn near every
other metal.
 
I read in sci.electronics.design that cpemma <me@privacy.net> wrote (in
<c0g815$15p2kr$1@ID-109861.news.uni-berlin.de>) about 'PCB Photoresist
Chemical', on Thu, 12 Feb 2004:
"Leon Heller" <aqzf13@dsl.pipex.com> wrote in message
news:402b6198$0$34$cc9e4d1f@news.dial.pipex.com...


Adam S. wrote:


Robert Baer wrote:

Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).


Corrosive to what ?, sodium metal?

Lead springs to mind - lead pipes are more dangerous with soft water.

But traces of chloride ion make water much more corrosive on damn near every
other metal.


Well, this is one of those Usenet 'true, but...' things. Lead chloride
is soluble in water, so traces of lead chloride get into water that is
virtually free of carbonate ions - 'soft' water. 'Hard' water, with
carbonate, forms an insoluble coating on the inside of lead pipes - you
can see a sort of fawn coloration.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
In article <9f6c9f5d.0402112309.5a436cbf@posting.google.com>,
Animesh Maurya <animesh_m@eudoramail.com> wrote:
Hi everybody,

Sorry, although this is not anyhow related with electronics,
but I think you people can me.

Can anybody exactly mention which chemical is used to photoresist PCB.
Last I checked, the dominant resist is a dry film that is heat
laminated on the board. Dupont "Riston", or something
like that. Maybe there's a MSDS (chemical safety form) on the
web for it that would tell the active ingredients.

There are a zillion types of photoresist, etchant, and plating
solutions. Try Coomb's "Printed Circuits Handbook".

Mark Zenier mzenier@eskimo.com Washington State resident
 
"Adam S." wrote:
Robert Baer wrote:
Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).

Corrosive to what ?, sodium metal?
*EVERYTHING*
Plastics, glasses, metals, minerals, other liquids and gasses,
anything - except nothing (ie a vacuum).
Water is a *polar* molecule and that dipole moment is not exactly weak
in the chemical scheme of things.
If you get into serious work requiring pure water measured in the
megohms, you will find that the purest available water does not last
very long - as it dissolves the container and becomes less pure,
eventually becoming in equlibrium with the container material.
 
They don't call it the "universal Solvent" for nothing.

Robert Baer wrote:

"Adam S." wrote:

Robert Baer wrote:

Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).

Corrosive to what ?, sodium metal?


*EVERYTHING*
Plastics, glasses, metals, minerals, other liquids and gasses,
anything - except nothing (ie a vacuum).
Water is a *polar* molecule and that dipole moment is not exactly weak
in the chemical scheme of things.
If you get into serious work requiring pure water measured in the
megohms, you will find that the purest available water does not last
very long - as it dissolves the container and becomes less pure,
eventually becoming in equlibrium with the container material.
--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com
 
"Robert Baer" <robertbaer@earthlink.net> schreef in bericht
news:402C90E5.66E510FA@earthlink.net...
"Adam S." wrote:

Robert Baer wrote:
Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).

Corrosive to what ?, sodium metal?

*EVERYTHING*
Plastics, glasses, metals, minerals, other liquids and gasses,
anything - except nothing (ie a vacuum).
Water is a *polar* molecule and that dipole moment is not exactly weak
in the chemical scheme of things.
If you get into serious work requiring pure water measured in the
megohms, you will find that the purest available water does not last
very long - as it dissolves the container and becomes less pure,
eventually becoming in equlibrium with the container material.
Pity you can't train them to solve PCB-copper only.

petrus



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.572 / Virus Database: 362 - Release Date: 27-1-2004
 
mzenier@eskimo.com (Mark Zenier) wrote in message news:<c0j425$p32$1@eskinews.eskimo.com>...
In article <9f6c9f5d.0402112309.5a436cbf@posting.google.com>,
Animesh Maurya <animesh_m@eudoramail.com> wrote:
Hi everybody,

Sorry, although this is not anyhow related with electronics,
but I think you people can me.

Can anybody exactly mention which chemical is used to photoresist PCB.
If you are looking for photo-resist, Think and Tinker has some dry
film. I've used it and it works very well down to 5mil traces, if
you know what you are doing.

Sam
 
Robert Baer <robertbaer@earthlink.net> wrote in message news:<402B3A5B.95ED89E2@earthlink.net>...

In the "good old daze" of hand-layouts ("taping"), Kodak Photo Resist
(KPR) was commonly used, along with KMER.
However, an el-cheapo way is to use egg-white sensitized with
Potassiun DiChromate.
Exposure to UV in either case polymerized the material, allowing the
solvent to wash away the un-exposed material.
For the sensitized egg-white, warm water is the developer, and one can
do some careful baking to achieve a more robust covering.
Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).
Ordinary water is bad enough on mountains!
Thanks, Robert for the info.

In addition to KPR, I would also like to try out egg-white one.

Can you please put detailed preparation of it. What should be the
ratio of egg-white and Potassium Dichromate?

Thanks again,

Animesh Maurya
 
Animesh Maurya wrote:
Robert Baer <robertbaer@earthlink.net> wrote in message news:<402B3A5B.95ED89E2@earthlink.net>...

In the "good old daze" of hand-layouts ("taping"), Kodak Photo Resist
(KPR) was commonly used, along with KMER.
However, an el-cheapo way is to use egg-white sensitized with
Potassiun DiChromate.
Exposure to UV in either case polymerized the material, allowing the
solvent to wash away the un-exposed material.
For the sensitized egg-white, warm water is the developer, and one can
do some careful baking to achieve a more robust covering.
Be careful with that chemical; water becomes more corrosive as the
purity increases (no joke).
Ordinary water is bad enough on mountains!

Thanks, Robert for the info.

In addition to KPR, I would also like to try out egg-white one.

Can you please put detailed preparation of it. What should be the
ratio of egg-white and Potassium Dichromate?

Thanks again,

Animesh Maurya
Cannot say, i only heard about that, and seen an equivalent using a
variant of Elmer's glue.
I do not think you need very much, as potassium dichromate is a rather
powerful oxidizer.
Try adding just enough to get a pink mixture.
Powedered egg-white is easily available and seems a lot less expensive
than using whole eggs for the source.
 
Mark Zenier wrote:
In article <9f6c9f5d.0402112309.5a436cbf@posting.google.com>,
Animesh Maurya <animesh_m@eudoramail.com> wrote:
Hi everybody,

Sorry, although this is not anyhow related with electronics,
but I think you people can me.

Can anybody exactly mention which chemical is used to photoresist PCB.

Last I checked, the dominant resist is a dry film that is heat
laminated on the board. Dupont "Riston", or something
like that. Maybe there's a MSDS (chemical safety form) on the
web for it that would tell the active ingredients.

There are a zillion types of photoresist, etchant, and plating
solutions. Try Coomb's "Printed Circuits Handbook".

Mark Zenier mzenier@eskimo.com Washington State resident
Riston has been a commonly used resist for ages.
 

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