Homebrew PCBs

Anyone tried using rubber cement as an overcoat or soldermask?  
Less flexible but probably more durable would be clear nail polish?

--- In Homebrew_PCBs@yahoogroups.com, "sethkoster" <sethkoster@...> wrote:
>
> 
>    Anyone tried using rubber cement as an overcoat or soldermask?  
> Less flexible but probably more durable would be clear nail polish?
>
It sounds like a good idea.   I haven't tried it yet.   No reason why
you couldn't try clear nail polish, rubber cement, and clear spray
lacquer all on the same board and see which one works best.

>Anyone tried using rubber cement as an overcoat or soldermask?
>Less flexible but probably more durable would be clear nail polish?

What temperature does **your** solder melt at? 

--- In Homebrew_PCBs@yahoogroups.com, "sethkoster" <sethkoster@...> 
wrote:
>

--- In Homebrew_PCBs@yahoogroups.com, "derekhawkins" <eldata@...> wrote:
>
> >Anyone tried using rubber cement as an overcoat or soldermask?
> >Less flexible but probably more durable would be clear nail polish?
> 
> What temperature does **your** solder melt at? 
> 


Probably approximately the same as yours.

I was thinking more of a post soldering protectant (overcoat), but I'd
be interested in what people use as a soldermask as well.

>I was thinking more of a post soldering protectant (overcoat)

Clear sprays (Krylon Clear etc.) were once popular during the thru 
hole days when there were well defined component and solder sides to a 
board. These days, most of us just prevent the copper from tarnishing 
any which way we can but this is usually done before soldering (Liquid 
tin, Tinit, solder paste etc.).

--- In Homebrew_PCBs@yahoogroups.com, "sethkoster" <sethkoster@...> 
wrote:
>

--- In Homebrew_PCBs@yahoogroups.com, "derekhawkins" <eldata@...> wrote:
>
> >I was thinking more of a post soldering protectant (overcoat)
> 
> Clear sprays (Krylon Clear etc.) were once popular during the thru 
> hole days when there were well defined component and solder sides to 
a 
> board. These days, most of us just prevent the copper from tarnishing 
> any which way we can but this is usually done before soldering 
(Liquid 
> tin, Tinit, solder paste etc.).
> 
> --- In Homebrew_PCBs@yahoogroups.com, "sethkoster" <sethkoster@> 
> wrote:
> >
>

I have always used Shellac to protect the newly etched PCB. Shellac is 
made by dissolving commercial Shellac flakes in methylated spirits. 
French polish is the same thing. Also I have a tin of product from the 
hardware store and it is known as "Patent Knotting."

The Shellac goes on the colour of varnish and prevents oxidation and 
can be soldered through. It appears to react like a flux when soldering 
through it.

On Thu, 13 Jul 2006 03:13:43 +0200, warrenbrayshaw  
<warrenbrayshaw@paradise.net.nz> wrote:

>
> I have always used Shellac to protect the newly etched PCB. Shellac is
> made by dissolving commercial Shellac flakes in methylated spirits.
> French polish is the same thing. Also I have a tin of product from the
> hardware store and it is known as "Patent Knotting."
> The Shellac goes on the colour of varnish and prevents oxidation and
> can be soldered through. It appears to react like a flux when soldering
> through it.



I use colophony resin. Basically tree resin with the turpentine removed.  
It's the same flux as used in rosin core solder wire. If given enough time  
to dry a laquer made of this will be dry and hard to the touch, although  
it does stay sticky longer than normal laquer (i believe this may be  
caused by water in the impure alcohols). It protects against corrosion,  
and acts as a flux during soldering. While it may not be ideal for the  
highest impedance circuits i have not had any problems so far.
I used (and still use) a ready-made spray can version of it, but i spotted  
colophony chunks at the chemicals shop, very good almost transparent  
quality. The lighter in color it is the lighter the flux residue will be,  
the dark brown stuff looks awful after soldering. The chunks can be solved  
in alcohol just like shellac to make a laquer.
I've also molten colophony into the little compartments at the end of my  
solder spool (the compartments to keep the plastic stiff). It's great to  
help with tinning wires.

I always thought shellac is a tree resin, but now i looked and it is  
actually produced by a beetle. I had no idea..

ST

Overcoating suggestion:

I've started using "Future" acrylic floor wax to prevent the copper traces
from oxidizng. Just wipe a thin film on and let it dry. Soldering though it
is no problem.


TANSTAAFL!

Myc

On 7/13/06, Stefan Trethan <stefan_trethan@...> wrote:
>
> On Thu, 13 Jul 2006 03:13:43 +0200, warrenbrayshaw
> <warrenbrayshaw@...> wrote:
>
> >
> > I have always used Shellac to protect the newly etched PCB. Shellac is
> > made by dissolving commercial Shellac flakes in methylated spirits.
> > French polish is the same thing. Also I have a tin of product from the
> > hardware store and it is known as "Patent Knotting."
> > The Shellac goes on the colour of varnish and prevents oxidation and
> > can be soldered through. It appears to react like a flux when soldering
> > through it.
>
>
>
> I use colophony resin. Basically tree resin with the turpentine removed.
> It's the same flux as used in rosin core solder wire. If given enough time
> to dry a laquer made of this will be dry and hard to the touch, although
> it does stay sticky longer than normal laquer (i believe this may be
> caused by water in the impure alcohols). It protects against corrosion,
> and acts as a flux during soldering. While it may not be ideal for the
> highest impedance circuits i have not had any problems so far.
> I used (and still use) a ready-made spray can version of it, but i spotted
> colophony chunks at the chemicals shop, very good almost transparent
> quality. The lighter in color it is the lighter the flux residue will be,
> the dark brown stuff looks awful after soldering. The chunks can be solved
> in alcohol just like shellac to make a laquer.
> I've also molten colophony into the little compartments at the end of my
> solder spool (the compartments to keep the plastic stiff). It's great to
> help with tinning wires.
>
> I always thought shellac is a tree resin, but now i looked and it is
> actually produced by a beetle. I had no idea..
>
> ST
>
>
>
> Be sure to visit the group home and check for new Links, Files, and
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>
>
>
>


[Non-text portions of this message have been removed]

>I've started using "Future" acrylic floor wax 

I'm assuming that after you solder you're going to have flux residue 
and burnt polish residue around joints....What cleanup solvent do you 
use that doesn't also remove your wax coating in the area and create an 
unholy mess? This applies to the other suggestions where the protective 
coating is applied before soldering as well. Needless to say these 
coatings seem to preclude a reflow job in an oven for any oddball SMDs.

--- In Homebrew_PCBs@yahoogroups.com, "Myc Holmes" <mycroft2152y@...> 
wrote:
>

On Thu, 13 Jul 2006 16:13:57 +0200, derekhawkins <eldata@...> wrote:

>
> I'm assuming that after you solder you're going to have flux residue
> and burnt polish residue around joints....What cleanup solvent do you
> use that doesn't also remove your wax coating in the area and create an
> unholy mess? This applies to the other suggestions where the protective
> coating is applied before soldering as well. Needless to say these
> coatings seem to preclude a reflow job in an oven for any oddball SMDs.


Colophony can be just left as it is.

You can put SMD paste straight on it and reflow, it won't do any harm. The  
SMD paste should use a flux you can keep on the PCB without fearing  
corrosion though.

ST

>Colophony can be just left as it is.

It can withstand 500F without breakdown? What do the joints look like 
after soldering and without cleanup?

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>

On Thu, 13 Jul 2006 17:00:52 +0200, derekhawkins <eldata@...> wrote:

>
> It can withstand 500F without breakdown? What do the joints look like
> after soldering and without cleanup?


It really depends on the quality used.
It is the same as with rosin core solder. Some leave a residue that is  
almost clear as glass (or at least lighter than PCB material), some leave  
a black ugly gunk.

If you stick a soldering iron into colophony it will melt, and smoke  
slightly, but basically not darken much.

ST

>It really depends on the quality used.

The point I'm trying to make is that cleanup with a solvent after 
soldering is best avoided, even if desirable, with anything less than 
real soldermask or a metal coating (Tin, solder paste etc.). This is 
something to consider when choosing a protective coating. If you don't 
really care how your solder joints look then it's a nonissue.

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>

On Thu, 13 Jul 2006 21:00:59 +0200, derekhawkins <eldata@...> wrote:

>
> The point I'm trying to make is that cleanup with a solvent after
> soldering is best avoided, even if desirable, with anything less than
> real soldermask or a metal coating (Tin, solder paste etc.). This is
> something to consider when choosing a protective coating. If you don't
> really care how your solder joints look then it's a nonissue.


Well, i guess the disputed point is that solder joints with any sort of  
flux residue do not look good, which i don't agree with.


ST

>Well, i guess the disputed point is that solder joints with any sort 
>of flux residue do not look good, which i don't agree with.

Not quite, the point is that there is no recourse in the event flux and 
decomposed coating residues or the result of an overlooked dirty 
soldering iron tip do not look good after soldering.

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>
> On Thu, 13 Jul 2006 21:00:59 +0200, derekhawkins <eldata@...> wrote:
> 
> >
> > The point I'm trying to make is that cleanup with a solvent after
> > soldering is best avoided, even if desirable, with anything less 
than
> > real soldermask or a metal coating (Tin, solder paste etc.). This 
is
> > something to consider when choosing a protective coating. If you 
don't
> > really care how your solder joints look then it's a nonissue.
> 
> 
> Well, i guess the disputed point is that solder joints with any 
sort of  
> flux residue do not look good, which i don't agree with.
> 
> 
> ST
>
Using Shellac as a coating may not be good when SMD is involved but 
is fine for single sided through hole boards.

If your soldering produced unsightly flux residues then solder flux 
can be cleaned of with whatever you usually use. This will likely 
remove the shellac coating as well but is only a matter of applying a 
further flash coat as a final step. The advantage of the shellac 
solution being a mixture of beetle and methylated spirits (Meths) is 
its quick drying properties. It should be widely avaiable at 
woodworking outlets.

If you make a bad job of applying it, just brush meths over it until 
it looks good. As this suggests, it can forever be reactivated with 
the meths. This all works well with fibre glass PCB but the cheaper 
phenolic board goes soft with meths so applying a shellac coating is 
fine but keep large quantaities of meths away from it as the board 
will go sticky. 
     
In all, its a cheap way of preventing oxidation of your finished 
board. I have 20yr old boards that still look great. Well lets say as 
good as a copper track with solder pads at each end can look. This is 
where the aesthetics and performance of the tin or solder mask 
techniques take over.

>Using Shellac as a coating may not be good when SMD is involved but
>is fine for single sided through hole boards.

Just about any spray could work for single sided through hole boards 
provided it was applied **after** soldering. I used to use Phenolic 
boards, Cool-Amp (silver coating) and Krylon clear spray, here is an 
example;

http://www.pbase.com/eldata/image/63450959

The Cool-Amp wasn't necessary but the silver coating looked better 
than bare copper. Why would you want to apply the Shellac before 
soldering for single sided through hole boards?

--- In Homebrew_PCBs@yahoogroups.com, "warrenbrayshaw" 
<warrenbrayshaw@...> wrote:
>