Making PCBs from a photo copy

[RobB]

It had been ten years or so since I last made a PCB.  Back then it was a complex procedure involving a transparency, UV lights, resist solution etc.  

I was keen to give the glossy photo paper method a go but couldn’t find any, so I decided to try ordinary photocopy paper.  

It occurred to me that the main disadvantage of ordinary paper could be that the toner may adhere too well to the porous surface.  To overcome this I decided to run the paper through the machine more than once.  After three times the black toner took on a glossy look, it was obvious there was plenty there.  Lucky for me the photocopier at work seems to have a fairly accurate feed mechanism so blurring wasn’t an issue.  

After ironing and soaking, it took 15 min to rub the paper fibres off with a sponge under running water.  Then I etched and it came out much better than I expected.  There was so much toner there that when I tried to remove it with a green scouring pad and kitchen cleaner (Ajax) I realised I was wasting my time.  Soaked it off with paint thinners instead.

Apart from the time saving of not having to remove paper fibres, is there really an advantage to using photo paper?

Also, I remember using a tinning solution to finish PCBs back then.  Is that stuff still available?

[Paul Perry (Frostwave)]

RobB, what kind of copier do you have?
(good to know SOMEBODY in Melbourne got something done today..)

[RobB]

It's the one at work.  Didn't think to look at the brand name.  It's black and white, has all the bells a whisles and would be around two-three years old.

[R.G.]

Also, I remember using a tinning solution to finish PCBs back then. Is that stuff still available?

Yes. In the USA, the trade name is "Tinnit".

[ExpAnonColin]

I think that it doesn't make a huge difference, the difference really is the amount of toner.  I can imagine that the toner would also go into the photopaper as well.  Sounds like 2 copies will do the job, eh?

-Colin

[Mark Hammer]

I would suggest it *does* make a difference.  The reason that PnP can work is that the toner can fuse to the copper more firmly than the blue emulsion can remain adhered to the acetate sheet.  Essentially, the whole rest on a "tug-of-war" where one contestant loses out to the other.  Although heaping on toner helps with the fusing to the copper, it does nothing to what goes on with respect to the paper.  The reason why glossy photo paper can work (and I'm loving it these days) is that the emulsion layer which provides the glossy surface can become detached from the paper backing.  The toner is simply the "glue" (and of course, more and better glue is a *good* thing).  Really and truly, it is the glossy emulsion that provides the real etchant resist, the same way it is the blue stuff that provides the etchant resist for PnP.

[Paul Marossy]

I use the plain copy paper method, but at best, I only get some of the pattern to stick to the blank PCB. That is with the copier set to the darkest it will do. I usually go over the whole thing with a Sharpie fine point marker before I etch it. I suppose it may depend on what kind of paper you use, too.

[Aharon]

I got really good at making PCBs with PnP blue.
The secret is in the iron temperature and I guess for every iron brand there's a slight difference in the setting.I use an old Brother HL6 laser printer on the medium setting.
The cleanning of the board is important but I've heard ridiculous claims that people will go through a million steps to clean a board before transfering the PnP.
Sand it with fine grit sandpapaer,wash it with alcohol and you are ready to go.
If the temp is right 30 secs on top of the transfer and ready again.
Quench for another 30 secs in a bowl of  cold water and presto.
I just made a board for the 301 and it made me sick how good it came out.No blurs,no bleeds,no missed spots.
I guess I'll try super glossy photo paper next but if I have to spend 2 hours scraping paper residue from the board like I did with the regular
glossy, PnP looks good again even at a higher price.
Aharon

[RobB]

In the USA, the trade name is "Tinnit".

Thanks RG, that's the stuff.

I use the plain copy paper method, but at best, I only get some of the pattern to stick to the blank PCB.

If you have access to the paper tray, try reloading the same sheet a couple of times.  You may not need your fine point marker.  

I might get a copy of the pattern made at a mini photo lab next time so quality of the PCBs can be compared.