Homebrew PCBs

Warren,
On a practical note, the SEARS ES powder works fine as a solder mask. the
particle size is a bit larger than the toner powder. It is cheap and
readily available..

I use a MARVY embossing tool for fusing. It is basically a hot air gun that
has low air flow. It also works great for smt. A hot plate should also work.

I use a green 3M scrubbie to remove the toner after etching. I found that
solvents tend to stain the pcb.

Myc



On Sun, Oct 19, 2008 at 2:30 AM, warrenbrayshaw <
warrenbrayshaw@...> wrote:

>   Myc
> That's good information. Colored toner is expensive but you can buy
> single bottles of refill toner. Still may exceed some budgets.
>
> I Googled for information, prompted by your remarks, and soon spotted
> a preferable route when selecting a powder. Electrostatic powders come
> in two varieties ThermoPlastic and ThermoSetting. Laser Printer toner
> must be ThermoPlastic otherwise the "Toner Transfer" method would not
> work. It will re-melt on reheating whereas the second will not as it
> undergoes a molecular change during heating and curing. As board
> soldering takes place after the silk screening the writing will likely
> survive better if the Thermosetting powder is used. The sources you
> list may not make it clear what type is on offer but a simple reheat
> test should reveal the answer.
>
> As these powders melt between 160 and 210 degrees C they will all be
> in the melt range in a SMD oven cycle so the ThermoPlastic will reflow
> also. This may not be an issue but I feel that the more stable
> ThermoSetting powder would be better especially when using a soldering
> iron or heatgun, that may disturb the toner/ES powder writing. (ugly).
>
> For use as an etch resist the opposite is true. I suspect it would be
> best to use the ThermoPlastic variety as it should be easier to remove.
> (To quote Wikipedia) "Methylene Chloride is generally effective at
> removing powder coating, however most other organic solvents (Acetone,
> thinners, etc.) are completely ineffective."
>
> As Acetone takes off laser Printer toner easily the thermo plastic
> being referred to could well be of another type. Something to be
> discovered.
>
> Plenty to go on with
> Warren
>
>
> "Myc Holmes" wrote:
> >
> > Warren,
> > Colored toner tends to be very expensive, especially when you have
> to buy
> > all 4 colors at once.
> >
> > SEARS has small packets of an electrostatic paint powder that works
> very
> > well. It comes in many colors. I have used the green for solder mask.
> >
> > There are other ES paint powders, guys who make their own fishing
> lures use
> > some very bright colors (even white). BASS sports hops has small
> bottles for
> > around $6.
> >
> > The craft stores have "embossing" powder that may work, but I
> haven;t tried
> > it yet.
> >
> > I have been using a MARVY hot air embossing tool to fuse my toner dusted
> > pcbs. You can see the toner turn shiny and fuse.
> >
> > Myc
>
>  
>


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