Dennis,
Thanks much for posting that. It's the whole works on
one page! So far I have been jurking here for a few years
just reading stuff. I have never made any pc boards. All
of my work is either wire-wrapped or soldered on those
generic "junk" boards. I have had excellent results using
Vector #3677 prototyping boards, and they fit right into
a card cage. However, reading your instrcutions gets me
curious about at least trying a pc board sometime just to
see what it's all about.
Chuck Richards
>
>
>---- Original Message ----
>From: wagelec@...
>To: Homebrew_PCBs@yahoogroups.com
>Subject: RE: [Homebrew_PCBs] Thoughts on tt etching and soldering
>Date: Mon, 03 Sep 2007 14:56:55 -0000
>
>>New to the group first I want to thank all of you for your help. The
>>techniques described here have helped me very much. Second I would
>>like to share my best techniques on making my own pcbs. Many if not
>>all I discovered from this group collective thoughts. So this is
>>probably more of an affirmation than a discovery.
>>
>>I've found that the printer makes all of the difference from success
>>to failure. I had an old Epson Laser 1000 that I was using and as
>the
>>toner got lower and lower I found that it became impossible to make
>>any toner transfers that I could even use. I purchased a new Dell
>1720
>>and now it's difficult to even make a tt with imperfect results. I'm
>>currently down to 12 mill traces with no problems and with probably
>>try 10mils but I believe that is going to be the limit for me. (See
>my
>>photos called dwags projects). I use an old iron and PressNPeel.
>>PressNPeel is a lot cheaper if you order from their website 20
>sheets
>>for 33 dollars. And for my low volume this is great.
>>
>>As for iron on techniques it is a learned exercise but I have found
>>that the color of the traces through the blue transparency of
>>PressNPeel gets darker and less fuzzy. That change in appearance
>>corresponds with a correct transfer of the toner and signals an end
>to
>>the iron heat and pressure. Heat can be checked with thermometer if
>>you have one find the heat setting that corresponds with about 300
>deg F.
>>
>>For etching I use Hydrogen Peroxide (Wal-Mart 1qt for 99 cents) and
>>Muratic Acid 4.99 a gallon. In the summer I mix three parts H202 to
>>one part HCL and in the winter I usually mix two to one. The removal
>>of copper works quicker if you can expose the copper to air and let
>>the etching completely drain off then submerge and do again. Takes
>>about 10 minutes to etch a 4x6 1oz copper pcb. Muratic acid is very
>>strong and I urge you unless you are familiar with strong reagents
>>please study safety and storage and waste removal of the etching
>>before you use this technique. I always have a five gallon bucket
>full
>>of water nearby incase of any accidents or spills when I am etching.
>>
>>After etching I remove the toner with acetone wash in a cold
>solution
>>of soapy water to remove any traces of acidity dry and then coat
>with
>>a light coat of Shellac. This prevents the copper from oxidizing and
>>makes soldering a dream. Make sure you use shellac and not a lacquer
>>or varnish. Shellac has a low melting point 180 deg F and makes an
>>excellent protective insulating coat for the bottom of the pcb. I
>>only know of one manufacturer of Spray shellac Zinsser and sometime
>>you can find it at Lowes. Or you can order it online
>>
>>After the shellac has dried drill out the holes. I found a great
>>source of drills on ebay you get 50 carbide ring drills for 32.00
>>shipping included. They come in 10s of .024, .029, .033, .035, and
>>.045 diameter onpasinc.com out of Ohio. If you make your entire pad
>>holes diameter less than the diameter of the drill you intend to use
>>the etched hole in the center of the pad with act as a center punch
>>and the drill with find the exact center. Start it slowly and let
>the
>>pcb move slightly to accommodate the centering process.
>>
>>Soldering is straight forward. As you apply heat to the pad you will
>>see the shellac boiling away this gives you an indication of where
>and
>>how much heat is being applied. When it boils away you have perfect
>>unoxidized copper exposed that can be soldered without any
>additional
>>flux.
>>
>>After the board is assembled I usually brush vigorously with a small
>>bronze brush. This dulls the solder to a mate finish and makes any
>>imperfections or bad weld very easy to spot with a magnifying glass
>>and removes all flux spatters.
>>
>>Finally after the board is tested and everything works correctly I
>>give it a final heavy coat of shellac.
>>
>>Again Thanks for all of your help and I hope these comments help
>>someone new to this group
>>
>>Dennis
>>
>>
>>
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