wot a mess with press n peel

[3v0]

Very. Mostly water. It's enough to get a reaction - turns the board pink, and quickly shows up grease or fingerprints. This was recommended back in the days of DIY photoresist application.

I would worry about the etchant taking the tooth off the scuffed up copper. I have not done this so I do not know.

 

[Mickster]

I'm doing something really wrong, aren't I?
Can anyone suggest why?
Thanks

There have already been suggestions about board cleanliness prior to tranfer and that is a vital step.

Firstly, your board should be clean and free from oxides/oily contaminants.

I normally use this process:
1. Wash the board with warm soapy water, then dry with a fresh paper towel.
2. Buff the board with 00000 steel wool, then wash with soapy water again & dry with paper towel. This removes most of the oils transferred from the wire wool, which stop it from rusting.
3. Wipe the whole board with Acetone on a new paper towel, to remove any remaining oils, then whilst the board is still damp from the Acetone, only handle the board by the edges during the next steps.
4. With another fresh paper towel, making sure not to touch the side you are using on the board, wipe the board again to "dry" it.
5. Shake the board in free air a little, to dislodge any paper fibres.
6. Immediately place the toner print on the board and the iron on the toner print, with the iron on the hottest setting. Hold the iron static for about 2 minutes at first, to get good adhesion before lifting the iron and having it move the print around.
7. Switch the orientation of the iron, since most modern irons have holes to let steam out during "normal" use. Try to ensure that even pressure is used.
8. After about 5 to 6 minutes of ironing, let the board cool, then remove the transfer paper.
9. Inspect the board throughly with a bright light and tilt it into many different positions. Any defects should be visible and minor ones can be carefully touched up with a resist pen or a "Sharpie".
10. If not satisfied, start over.

 

[HarveyH42]

My god! 7-8 minutes with an iron? Holy Jesus!!! Maybe that is why I got no results with plain paper before buying a laminator. I run the board through, flip it over, run it a second time, and its done. Might take 7-8 minutes, if you count the time it takes to turn on the power and wait for it to heat up, maybe 30-40 seconds for a 2x3 inch board. Best investment I made. I use a 4" surplus laminator, paid $25...

I went from plain and photo paper, straight to Pulsar (Florida based company ), never tried P-n-P.

 

[UTMonkey]

Hi All,

I have just acquired a laminator for PCB making and just wondered, why "flip it over"?

Mark

 

[3v0]

Hi All,
I have just acquired a laminator for PCB making and just wondered, why "flip it over"?
Mark

More even heating, thinking maybe only one roller is heated or one is hotter then the other. But it also helps keep track of how many trips each board has made.

 

[HarveyH42]

I don't know why I flip the board. Not even sure if I need to pass it through twice. I just wanted to make sure it transferred okay the first try. I had to a lot of failures with a clothes iron (pretty much every one), and it's not fun cleaning the copper, ironing and hoping this one might at least be usable... I seldom get a bad board with two passes through the laminator, so why change. I use to be a little careless handling the copper, and get finger prints on the edges. I leave a wider border, and take greater care picking up the copper and placing the transfer.

 

[3v0]

You make a good point about leaving a wide edge. It seems the trace on the edge of the PCB is the one most apt to fail. I often place a sacrifical aprox .016 in dimension line around the board.

 

[astronomerroyal]

I heard something that seemed like an excellent suggestion; wiping the board with etchant during the cleaning process. Nothing like etchant to give you a new copper surface.

 

[Angry Badger]

Hi All,

I have just acquired a laminator for PCB making and just wondered, why "flip it over"?

Mark

Hi,

What brand / model laminator did you get? What thickness board are you using and has it been a success?

I just bought a laminator of ebay (£6) but it won't accept my pcb (1.6mm). Jams up. It's just a little ID card laminator (Rexel LP10). I'll have to look for something else and want to get the right one next time.

Most laminators seem to have a max thickness allowanace of 300microns, a few have 500. Can you really get a 1.6mm pcb through one of those?

Thanks.