Finally got the whole laser printer toner tranfer thing to work.

Discussion in 'The Projects Forum' started by Evil Lurker, Feb 1, 2015.

  1. Evil Lurker

    Thread Starter Member

    Aug 25, 2011
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    Suffice to say I'm pleased. After a whole bunch of wild goose chases I finally got the whole laser printer toner transfer thing to work with fairly decent results. Turns out the solution for me was to skip trying to use the photo paper and go with an Avery printable label sticker backing sheet. Basically the entire process involves wet cleaning the board with steel wool using dish washing detergent followed by wiping down with acetone, preheating the board @170 degrees in my convection oven, then pressing about ~45 seconds with my clothes iron. After a bit of cooling and gentle rubbing with the edge of a credit card the before lifting up the sticker label backing sheet the toner comes right off. Right now the smallest thing I have tried doing is around 20 mils with no problem.

    Guess the next step is to acquire some tinnit electroless plating solution and start working on dual sided boards. I'm thinking the best way to accomplish that is going to be to see if I can use a friends custom design t-shirt press as it would allow both sides of the board to be transferred at the same time. Still haven't figured out a good way to plate my vias though as one of the chemicals needed to do that can also be used to cook meth and as such is banned in the USA. Closest solution I have found so far are some small tubular copper rivets set into the board but those are somewhat expensive.

    One idea I have been tinkering with is to use wire sliced into tiny cylinders using three flat pieces of steel bolted together sort of like a pocket knife. The wire goes into a hole drilled the same size as the wire across all three pieces, with the center piece being allowed to "stick up" just a little bit like a partially opened pocket knife. Giving the center "blade" a blow with a hammer drives the center blade level with the outer ones and effectively shears the wire cleanly leaving a slug the width of the blade with square ends. To install the slugs into the board the idea is to again drill out a hole the size of the slug and to use a small arbor press. The press has a couple thingys on it made from broken carbide drill bits ground down with a diamond cutoff wheel in a rotary tool leaving what could be described as a flat end with a small "nub" in the center. It's actually quite easy to do using a drill to turn the bit in the opposite direction the rotary tool is turning. When the cylinders are pressed the nubs will "mush" the center of the copper slug causing it to expand it's diameter slightly and grip the PCB. A little bit of solder on the ends of the via and it should be good to go.
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,866
    988
    Try Scotch Brite pads instead of the steel wool. Steel wool can leave behind tiny bits of pad that you might not pick up in your follow up cleaning.

    What happens if you need to make several tires and don't have backing on hand? Could be an expensive process to sacrifice a new sheet jsut for the backing.

    Give wax paper a try. Nice benefit is that it is semi transparent making it easier to line things up.
     
  3. Evil Lurker

    Thread Starter Member

    Aug 25, 2011
    117
    23
    IMO, steel wool is good as it physically removes the oxidation from the top of the board. And for what it is worth I did use a scotch brite pad afterwards since it was already at my sink.

    As far as the printing goes it is easy using DipTrace. Set your board outline the same size as a regular sheet of paper (which is the same for the label backing paper), lay out your board as you normally would, and when you are done highlight the finished circuit, group the components traces and copper pours, then simply copy and paste. I generally do 3.4 boards worth of circuits in one printing, cut them out, and if I want to make more simply turn the paper around on the uncut square end and run it through the printer again. You can't do that with Eagle as you are limited by max board size... unfortunately with the free version of DipTrace you can only do 300 pins but on the upside as long as your boards are small you can make many "panelized" copies one giant board.

    Speaking of Eagle, I have decided that is about the most counter intuitive, difficult to learn how to use, mother %&$#ing time vampire of a program EVER. Diptrace is simple. Virtually every component you can think of is included in the library... well not exactly but the "generic" footprints of standard pads used in the actual component library are there for everything from SMD diodes to electrolytic chip capacitors and even mini-usb SMD connectors. Even if you don't know exactly which pad layout goes with what it is easy to sift through them using the arrow keys on your keyboard till you find the one that works. And when you do get them on the board it is easy to modify them... I personally like to make the pads slightly larger so that I can use my iron to do SMDs.
     
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    I agree 100% and is why I always recommend diptrace..
     
  5. RichardO

    Well-Known Member

    May 4, 2013
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    I quit using steel wool to clean the resist from my etched boards. I concluded that the steel wool left material on the copper that gave me spotty coverage when doing electroless tin plating. I now use a Scotch Brite type of pad and Barkeepers Friend cleanser.
     
  6. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,866
    988
    Agree Eagle is horrible. Diptrace has some things I don't like but mostly easy to use. I wish diptrace had an option to list by part type instead of number. Connectors can be especially hard to find without a part number.
     
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