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How do you tin your boards? Looking good.
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
Sent: Sunday, January 10, 2016 2:42 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Heatless (cold) Toner Transfer for PCB making
I have been using toner transfer for years with my Brother printer and a Scotch Tl902 laminator, with great success. Only problem has been that I need to use a genuine Brother toner cartridge, and have had problems with a little over etching of larger copper pour areas. Saw this instructable, and thought I would give it a try, since my toner cartridge was almost out and the would have to order a new one soon. I have a couple generic cartridges that I use for general printing, but they have not worked well for making boards, so I thought I would give them a try.
Looking around at my painting stuff I had some denatured alcohol and a couple of different types of solvent. but no acetone. I tried a couple to see which one would dissolve toner, and found the Xylene that I used for thinning out some enamel worked well. I tried different mixtures and found 4 to 1 mixture of denatured alcohol to Xylene worked well. Printed a couple copies of a board layout on Hammermill color laser copy paper, and used a modified version of the method in the instructable. Using a eye dropper I placed a small amount of the mixture on cleaned boards and spread it around until I had a even coating on the board. I placed the laser print on the board and lightly pressed it down so it made even contact with the board. Then with the eye-dropper I flooded the back of the paper until it became nearly transparent and I could see the pattern through the paper. Waited about 30 seconds and covered the paper with a folded over paper towel, placed a small piece of board material on top and applied pressure for about two minutes. After that I removed the board and used the rounded back of a fork and burnished the board, first with the paper towel , and then without. After soaking the board in water and removing the paper, everything looked nice and crisp. Good adhesion over the entire board, and no voids that I could see. I etched the boards, and everything came out great. Nice clean lines, no breaks in any of the traces, good sharp clearance where I had traces going between pins, and very little problem with etch through on the large ground plane areas.
Looks like time to retire the old laminator. I will post some pictures of a completed board on my blog.
DuWayne
KV4QB.blogspot.com