Homebrew PCBs

Leon,     

I use the TT method and with care I can do 1 mil lines.
I can do 3mill without problems.

This is how I make the boards.

The best solution I have ever used is one part
muriatic acid(27% the kind used to clean bricks) 
and two parts hydrogen peroxide ( 3 % , the
kind you can get at Walmart or drug stores).

This will  etch in 5 - 6 minutes and does not need heat.
You mix only enough to cover the board in a small plastic tray.

The printer you use is very important(at least the toner is).
A brother printer will not work.
I use an HP P1505 and it works the best I have seen.
I think HP printer is part of why I get good resolution.

I clean the board very good. I use Synthetic Steel 
Wool 2 made by hodes/American to scrub the board 
first .Then I clean it with BAR KEEPERS FRIEND 
that you can get at Walmart. The cleaner the board 
the better.  Do not get finger prints(oil from fingers)on 
the board.  You might want to use latex gloves starting 
at this point.  After you scrub the board good with
BAR KEEPERS FRIEND wash it good with soap 
and cold water.  Now take some 91% alcohol and 
wipe the board clean.  Wipe until there is no residue
left on the wipe cloth.  Now put the board in an oven that 
is preheated to 350 degrees and let it stay for 
3 minutes.

Take the board out of the oven and put the toner paper 
on the board. Be careful at this point and lay the paper 
down easy because it will stick to the hot board.  Now lay 
a clean piece of cloth over the paper and iron the board 
for one minute.  Apply very light pressure as you move 
the iron all over the board.

Now put the board in water and let it soak for about 20 
minutes the paper will float off the board with very little help.  
Now after the paper is off put the board back in the oven 
for about 3 minutes. It is now ready to etch.

I print the circuit on some Laser Jet color paper that
I bought at Sams. It is made by a company named 
Royal Brights,  108 Main Street,  Norwalk,  CT 06851 
phone 1-800-526-4280. It is Glossy Ink  Jet Paper 200 
sheets per box,  this is all I can find on 
the box.  You could call them and find out where to get it.

The reason I use this paper is after you iron it on and soak
it about 20 minuter the paper will float off the board with 
very little help.  I think the paper is one reason I get such 
high resolution. 


  ----- Original Message ----- 
  From: leon Heller 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Friday, February 20, 2009 4:28 PM
  Subject: Re: [Homebrew_PCBs] Surface Mount


  ----- Original Message ----- 
  From: "jerrytr2.com" <jerry@...>
  To: <Homebrew_PCBs@yahoogroups.com>
  Sent: Friday, February 20, 2009 8:27 PM
  Subject: [Homebrew_PCBs] Surface Mount

  > Hello,
  >
  > Since encountering this group a month or so ago, I have refined my
  > toner transfer process to the point that I am able to reliably do 15-
  > mil traces. Maybe smaller. Hope so.
  >
  > I'm doing a home project and have settled on PIC24F
  > microcontrollers. The latest version needs USB, and all the PICs
  > that support USB are surface mount. So I have been dragged kicking
  > and screaming into the 21st century.
  >
  > I bought an Aoyue 968 hot-air SMD rework station and some fine
  > tweezers and have been having a good time scrounging parts off some
  > defunct computer boards - just to get used to the tool. I'm going to
  > need a microscope - half of these parts just look like bits of dirt!
  >
  > One part I scrounged is the same package as the 24FJ256GB106
  > processor I'm planning to use - a 64-pin TQFP. Good LORD those pins
  > are small. Can Toner Transfer make boards this tight? According to
  > the spec sheet, the pin pitch is .5mm, or about 20 thousandths of an
  > inch. So the traces need to be 10 thousandths of an inch, and will
  > only have 10 thousandths of separation. Ouch.

  Some people can do that sort thing with TT, but it can be difficult. I can 
  do fine pitch devices and 8/8 mil tracks with photo-etch without any 
  problems.

  Leon 


  

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