Homebrew PCBs

Check out this ebay auction:  300065847043

I had a very interesting telephone conversation today with Steve
Johnson who owns the company that makes this photoresist. Steve is
just getting this product off the ground after many years of research.
A water based photoresist is something the circuit board industry has
been waiting on for years. He said it was the only water based product
of this type on the market.

There are NO solvents or VOC's in this product. Steve told me it has a
slight water based (latex) paint odor. This would be great for anyone
with a home based shop who doesn't want to put up with the stink of
dry film or solvent based products. It can be processed the same as
dry film resist after it dries. 

Development would be in a weak sodium carbonate (soda ash) solution.
Washing soda from the grocery store is soda ash. Make a 1% solution
with water. Approximately 1.25 ounces of the dry soda ash powder to
one gallon of warm water should work fine.

Sodium hydroxide (lye) can be used to strip this resist after etching.
A 1 or 2% solution should work for stripping.

I plan on using this resist for photo engraving stainless steel sheets
for a product I make. Steve said this material has better adhesion
properties than dry film. Resist adhesion has always been a problem
for me when processing stainless steel. I will use it for my circuit
board production as well. My plan is to use a simple dip coater for
applying the resist and drying it with an infra red heater panel.

Something else to consider, this company also makes soldermask and
component legend products that exhibit the same fast exposure
properties. I have used liquid photo imaged soldermask for years and
if you don't have a high power exposure unit you aren't going to get
the job done. Those products take lots of UV power for proper
exposure. The way it looks, this new soldermask product will get a
complete exposure with much less power. This is a HUGE bonus for the
experimenter and home shop guys who don't have high power equipment.

I will be testing this product in my shop very soon and plan to post
the results here. Hopefully others will do the same as I feel they
will obtain some first class boards by doing so. 

Steve Johnson told me he would welcome orders from anyone so don't
worry about being a hobbyist or home based shop. He wants to get this
product out there and I applaud him for accepting orders from
commercial and hobbyist users alike.

I am not affiliated in any way with this company and only learned
about them today but I plan on being a regular customer and I hope
others will try it too. 

Tom

"twb8899" <twb8899@...> writes:
> Something else to consider, this company also makes soldermask and

Photoimagable solder mask?  Since you're not removing it, are the
remaining chemicals house-safe and easy to obtain?  The lack of a good
solder mask solution has always bugged me with TT home etching.

> The way it looks, this new soldermask product will get a complete
> exposure with much less power.

Hmmm... sunlight?

All of these aqueous materials are negative acting. Coat the blank
copper board and expose with UV light using a negative film. Any area
exposed to the light source will harden and not develop out leaving
traces that can't be attacked by the etchant. Etch the main circuitry
pattern and strip the etch resist in a weak lye solution. Now the
board is ready for soldermask.

After etching the copper image strip the primary etch resist, clean
the copper and dry the board. Now the board can be coated with liquid
photoimageable soldermask and dried. The artwork to expose the
soldermask will be clear with black opaque pads that block the UV
light from exposing any copper pads. Any area not exposed will wash
out during development and that area will now have exposed copper.
Some soldermask materials also need a second UV exposure or thermal
bake cycle after development for proper hardening of the developed
mask. That's the basics of photo imaged soldermask. After you do a few
boards and work out the process it becomes easy to do. 




--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:

>
> 
> "twb8899" <twb8899@...> writes:
> > Something else to consider, this company also makes soldermask and
> 
> Photoimagable solder mask?  Since you're not removing it, are the
> remaining chemicals house-safe and easy to obtain?  The lack of a good
> solder mask solution has always bugged me with TT home etching.
> 
> > The way it looks, this new soldermask product will get a complete
> > exposure with much less power.
> 
> Hmmm... sunlight?
>

----- Original Message ----- 

From: twb8899
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, January 04, 2007 6:14 AM
Subject: [Homebrew_PCBs] Re: Water soluble photoresist



All of these aqueous materials are negative acting. Coat the blank
copper board and expose with UV light using a negative film. Any area
exposed to the light source will harden and not develop out leaving
traces that can't be attacked by the etchant. Etch the main circuitry
pattern and strip the etch resist in a weak lye solution. Now the
board is ready for soldermask.

After etching the copper image strip the primary etch resist, clean
the copper and dry the board. Now the board can be coated with liquid
photoimageable soldermask and dried. The artwork to expose the
soldermask will be clear with black opaque pads that block the UV
light from exposing any copper pads. Any area not exposed will wash
out during development and that area will now have exposed copper.
Some soldermask materials also need a second UV exposure or thermal
bake cycle after development for proper hardening of the developed
mask. That's the basics of photo imaged soldermask. After you do a few
boards and work out the process it becomes easy to do.

-------------------------

Negative acting photoresist gives better resolution than positive, 
apparently, which is why most PCB manufacturers use it. That's one reason 
why I'd like to try it. The PCB software I use can generate negative 
transparencies.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

Leon,

Contact Steve Johnson and find out who distributes this product in
Europe. His email address is:  

sjohnson@... 

Since you have a way to make transparencies it won't be difficult at
all for you to try this product. The best part is the low odor when
processing this photoresist. I never did get used to the fumes from my
dry film laminator so I'm looking forward to working with this new
photoresist.

Tom

 
> Negative acting photoresist gives better resolution than positive, 
> apparently, which is why most PCB manufacturers use it. That's one
reason 

> why I'd like to try it. The PCB software I use can generate negative 
> transparencies.
> 
> Leon
> --
> Leon Heller
> Amateur radio call-sign G1HSM
> Suzuki SV1000S motorcycle
> leon355@...
> http://www.geocities.com/leon_heller
>

----- Original Message ----- 

From: twb8899 
To: Homebrew_PCBs@yahoogroups.com 
Sent: Thursday, January 04, 2007 12:20 PM
Subject: [Homebrew_PCBs] Re: Water soluble photoresist


Leon,

Contact Steve Johnson and find out who distributes this product in
Europe. His email address is: 

sjohnson@... 

Since you have a way to make transparencies it won't be difficult at
all for you to try this product. The best part is the low odor when
processing this photoresist. I never did get used to the fumes from my
dry film laminator so I'm looking forward to working with this new
photoresist.

---------------------------------------------

I've just sent him an email.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

--- In Homebrew_PCBs@yahoogroups.com, "twb8899" <twb8899@...> wrote:
>
> Check out this ebay auction:  300065847043
> 
> I had a very interesting telephone conversation today with Steve
> Johnson who owns the company that makes this photoresist. Steve is
> just getting this product off the ground after many years of research.
> A water based photoresist is something the circuit board industry has
> been waiting on for years. He said it was the only water based product
> of this type on the market.
> 
> There are NO solvents or VOC's in this product. Steve told me it has a
> slight water based (latex) paint odor. This would be great for anyone
> with a home based shop who doesn't want to put up with the stink of
> dry film or solvent based products. It can be processed the same as
> dry film resist after it dries. 
> 
> Development would be in a weak sodium carbonate (soda ash) solution.
> Washing soda from the grocery store is soda ash. Make a 1% solution
> with water. Approximately 1.25 ounces of the dry soda ash powder to
> one gallon of warm water should work fine.
> 
> Sodium hydroxide (lye) can be used to strip this resist after etching.
> A 1 or 2% solution should work for stripping.
> 
> I plan on using this resist for photo engraving stainless steel sheets
> for a product I make. Steve said this material has better adhesion
> properties than dry film. Resist adhesion has always been a problem
> for me when processing stainless steel. I will use it for my circuit
> board production as well. My plan is to use a simple dip coater for
> applying the resist and drying it with an infra red heater panel.
> 
> Something else to consider, this company also makes soldermask and
> component legend products that exhibit the same fast exposure
> properties. I have used liquid photo imaged soldermask for years and
> if you don't have a high power exposure unit you aren't going to get
> the job done. Those products take lots of UV power for proper
> exposure. The way it looks, this new soldermask product will get a
> complete exposure with much less power. This is a HUGE bonus for the
> experimenter and home shop guys who don't have high power equipment.
> 
> I will be testing this product in my shop very soon and plan to post
> the results here. Hopefully others will do the same as I feel they
> will obtain some first class boards by doing so. 
> 
> Steve Johnson told me he would welcome orders from anyone so don't
> worry about being a hobbyist or home based shop. He wants to get this
> product out there and I applaud him for accepting orders from
> commercial and hobbyist users alike.
> 
> I am not affiliated in any way with this company and only learned
> about them today but I plan on being a regular customer and I hope
> others will try it too. 
> 
> Tom
>

hi, as you describe the resist its most like screenprining emulsion to me
is it a two part product ! (sensitizer)

i have it, but never tryet using it that way :) 

Gr Roel

If I had to compare this resist to another product it would be the old
 Kodak KPR resist. KPR was a solvent based photo resist that was
processed in a xylene based chemistry. I worked with KPR many years
ago and certainly don't miss it or the solvent fumes. 

I still have an old DuPont Model C developing machine left over from
the old days. That's what we used to develop solvent based photo
resist coatings. Anyone who worked with KPR in the old days will agree
 that it's nothing they miss!! 

I think this new water based resist will catch on and become well
accepted. The hobby guy's will appreciate it because there is almost
no odor. It's a one part product with a long shelf life.


--- In Homebrew_PCBs@yahoogroups.com, "roel_cnc" <roel_cnc@...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "twb8899" <twb8899@> wrote:
> >
> > Check out this ebay auction:  300065847043
> > 
> > I had a very interesting telephone conversation today with Steve
> > Johnson who owns the company that makes this photoresist. Steve is
> > just getting this product off the ground after many years of research.
> > A water based photoresist is something the circuit board industry has
> > been waiting on for years. He said it was the only water based product
> > of this type on the market.
> > 
> > There are NO solvents or VOC's in this product. Steve told me it has a
> > slight water based (latex) paint odor. This would be great for anyone
> > with a home based shop who doesn't want to put up with the stink of
> > dry film or solvent based products. It can be processed the same as
> > dry film resist after it dries. 
> > 
> > Development would be in a weak sodium carbonate (soda ash) solution.
> > Washing soda from the grocery store is soda ash. Make a 1% solution
> > with water. Approximately 1.25 ounces of the dry soda ash powder to
> > one gallon of warm water should work fine.
> > 
> > Sodium hydroxide (lye) can be used to strip this resist after etching.
> > A 1 or 2% solution should work for stripping.
> > 
> > I plan on using this resist for photo engraving stainless steel sheets
> > for a product I make. Steve said this material has better adhesion
> > properties than dry film. Resist adhesion has always been a problem
> > for me when processing stainless steel. I will use it for my circuit
> > board production as well. My plan is to use a simple dip coater for
> > applying the resist and drying it with an infra red heater panel.
> > 
> > Something else to consider, this company also makes soldermask and
> > component legend products that exhibit the same fast exposure
> > properties. I have used liquid photo imaged soldermask for years and
> > if you don't have a high power exposure unit you aren't going to get
> > the job done. Those products take lots of UV power for proper
> > exposure. The way it looks, this new soldermask product will get a
> > complete exposure with much less power. This is a HUGE bonus for the
> > experimenter and home shop guys who don't have high power equipment.
> > 
> > I will be testing this product in my shop very soon and plan to post
> > the results here. Hopefully others will do the same as I feel they
> > will obtain some first class boards by doing so. 
> > 
> > Steve Johnson told me he would welcome orders from anyone so don't
> > worry about being a hobbyist or home based shop. He wants to get this
> > product out there and I applaud him for accepting orders from
> > commercial and hobbyist users alike.
> > 
> > I am not affiliated in any way with this company and only learned
> > about them today but I plan on being a regular customer and I hope
> > others will try it too. 
> > 
> > Tom
> >
> 
> hi, as you describe the resist its most like screenprining emulsion
to me

> is it a two part product ! (sensitizer)
> 
> i have it, but never tryet using it that way :) 
> 
> Gr Roel
>