Homebrew_PCBs

Another fellow was going to try using a heat gun after the toner
transfer process. Seeing as I messed up so good on my last two
boards and had to remake them, I figured I would give it a try.

I transferred the two circuits onto the boards - perfect transfers,
no pick ups or anything like that. This time I used the iron again,
set at 370 degrees F, and pressed 3 times at 10 seconds each time.
Each time I pressed, I made sure to move and rotate the iron a bit
so the steam hole areas were not on the same spot on the circuit
board. Really came out nice this time - very impressive.

I then took the heat gun and flashed over the circuit boards till it
appeared that the toner turned a bit glossy. My eyes are acting up
a bit today, so tomorrow I will look over the toner with a glass to
see if it looks like the toner "blended" together under the heat.


If time allows, I will etch and tin the boards tomorrow. Again,
will post results.

So far, that pulsar paper is working good for me, but frankly it is
expensive. However, if it works reliably, I don't mind the cost as
I don't do enough boards to justify another method using a cheaper
paper - yet.

Chris

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

> I then took the heat gun and flashed over the circuit boards till it
> appeared that the toner turned a bit glossy. My eyes are acting up
> a bit today, so tomorrow I will look over the toner with a glass to
> see if it looks like the toner "blended" together under the heat.
>

sounds promising.

>
> If time allows, I will etch and tin the boards tomorrow. Again,
> will post results.
>
> So far, that pulsar paper is working good for me, but frankly it is
> expensive. However, if it works reliably, I don't mind the cost as
> I don't do enough boards to justify another method using a cheaper
> paper - yet.
>

I use the same process with inkjet paper. The cost is very cheap.
The only issue is that it doesn't release as nicely.

Check it out!

In the files section, look for heatguntoner001.jpg it's a scan of the
board after etching. The scan does not show the glossy toner effect
from the heat gun. I looked at it with a loupe before etching and the
toner did look like it blended together pretty good (my eyes are not
the best, but it did look pretty good). The etching again, went very
good. Tomorrow I will wash off the toner to see what the copper looks
like but I suspect it is going to be pretty crisp looking. Under the
loupe, it appears as though I should have etched for another minute,
but it is pretty darn good looking so far.

I don't want to remove the toner in case there is something wrong,
don't want another "IFU" to sleep on :-)

Chris

Well, I just scanned the boards and posted the image in the files
section -- PCB-Friday001.jpg. Have a look, they turned out pretty
darn good.

Don't be alarmed by the burn marks, let me explain what you are
seeing.

After drilling all the holes, I printed out some transfers for the
silk screen artwork and transferred them to the component side of
the boards. One of the boards in the image show this. I then
realized making a two sided board is going to be pretty tough, but I
have a better idea of that now.

I then went about Derek's tinning process with the solder paste. I
have a number of butane powered torches so I thought I would give
that a try, I wouldn't recommend it. The heat is too focused and
hard to control. The heat gun, works much better, but you have to
keep it moving or you get burns like you see in the photos. The
burns are not as bad as they look in the scan, I think the shiny tin
sections threw off the brightness/contrast settings making it look
worse than it really is.

The tinning again went pretty easy. You can see that some areas are
heavier than others and some areas could have used a tad more heat
to get it to flow out. I would wager to say that getting the
lighting just right will greatly improve this part of the process.
Seeing what is going on is kind of tough - there is some smoke, but
not much. While heating the solder paste, you can see it melt and
turn shiny - this is part of the problem with seeing what is going
on. If you have a bright light on the far side and you are sort of
looking towards it, it blinds you a bit (like looking at a bright
light does).

I believe I have even got everything mirror imaged and oriented
correctly this time too. However, while drilliing the holes I
realized another error in my circuit - I forgot to put a resistor in
for the power indicator LED. You will see the repair as a large
drilled hole "breaking a trace" and on either side two smaller holes
to put in the resistor.

Well, I guess that's another lesson learned and another club to
join :-)

If anyone has questions, feel free to ask, sooner rather than later
as I know I will start forgetting everything I did :-(

Chris






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

> Check it out!
>
> In the files section, look for heatguntoner001.jpg it's a scan of

the

> board after etching. The scan does not show the glossy toner

effect

> from the heat gun. I looked at it with a loupe before etching and

the

> toner did look like it blended together pretty good (my eyes are

not

> the best, but it did look pretty good). The etching again, went

very

> good. Tomorrow I will wash off the toner to see what the copper

looks

> like but I suspect it is going to be pretty crisp looking. Under

the

> loupe, it appears as though I should have etched for another

minute,

> but it is pretty darn good looking so far.
>
> I don't want to remove the toner in case there is something wrong,
> don't want another "IFU" to sleep on :-)
>
> Chris

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

> Well, I just scanned the boards and posted the image in the files
> section -- PCB-Friday001.jpg. Have a look, they turned out pretty
> darn good.

I moved them into the Toner_Transfer folder. Nice!

Steve Greenfield