Toner detaches from copper during etching! Help!

[ChildOfVision]

Sorry, guys, I went a little off-topic, but these pinholes drives me crazy too...

...how do you cut your pcb before etching?

I saw it with a metal saw with fine teeth, the blade is under a blunt angle with respect to the PCB (nearly parallel), the cut is very clean and tidy, without damaging the board or copper.

Did you say you saw the toner detach from the copper while etching or if the copper being etched out from under the toner and then the toner falls off?

Toner is quickly separated from the copper, just keep floating to the surface in the form of tufts. The rest of toner remains firmly on copper until the end of etching. I do not know whether is the toner under etched first, and then falls off; I am trying to figure out this thing !

When the toner does not stay on the PCB most of the time the problem is that the laminator is not getting hot enough.

Therein is the great enigma: After laminating, toner withstand severe brushing with toothbrush and dish-detergent, without any damage or separation! Therefore I assume that the laminating is properly done.

You could also try hitting the PCB with 600 grit sandpaper to give the toner a better surface to stick to.

Yes, my research so far is going in this direction! Problems have occurred when I started to use the brand new FR-2 laminate which seems to be very clear; I assumed that sanding is not necessary, I'm only washed PCB well in detergent and cleaned thoroughly with acetone! Now I'm sanding each PCB, trying new and different kinds of paper, in order to get good and consistent results.

Using a hatched pattern for a pour (eagle has this) can help.

Yes, I try this also...

You can get a green foil from pulsarProFx.com that is laminated to the top of the toner to seal pin holes.

I allready have white TRF which I use for silkscreen (with "gummed paper"), but I do not know whether green TRF works with toner which has paper residues on the surface or toner must be pure without paper residues???

keep you fingers off the PCB surface after cleaning to prevent transfer of body oils

I always wear clean gloves after cleaning with acetone !

Anyway, thanks for the suggestions!

 

[3v0]

Obviously there is something wrong or it would work.

I doubt the green TRF will work with paper fibers hanging out of the toner.

Could be that these fibers are at least part of the problem. The pulsar paper is $1.50 a sheet and will put an end to fibers but seem to increase pinholes and the need for the green TRF. The paper is $1.50 a sheet or 1.5 cent per square inch. And you can get it from Mouser and Digikey so you do not have to make a special order.

There are people who do fine without it.

 

[ChildOfVision]

Obviously there is something wrong or it would work.

Well, so are you, guys, here to help me (did I spell it good ?)!
I've somehow managed to obtain before TRF White, but it is very difficult to get pulsar's products in my country, even through eBay. When TT Paper is available it costs about 25 USD with postage + a minimum of 16 USD for TRF Green! This is very expensive for my budget ! And, I can get it only through one vendor, on ebay (dipmicro)! Therefore, I must rule out all others kind of paper (including gummed paper) before!
Finally, you said: "There are people who do fine without it. "!

 

[3v0]

Where are you ?

It is possible to make a TTP like paper. I think it was DirtyLude (maybe) that came up with a way to use glue as a coating.

 

[ChildOfVision]

Croatia. Odd shaped country between Italy and Hungary!
I'm actually on the way to do this! I was thinking about the "white glue" stick - very inexpensive and elegant!

 

[3v0]

Croatia. Odd shaped country between Italy and Hungary!
I'm actually on the way to do this! I was thinking about the "white glue" stick - very inexpensive and elegant!

Yeah I can see your problem.

You will be interested in this thread.
https://www.electro-tech-online.com/threads/diy-toner-transfer-paper-cheap-and-easy.94601/

Just to let you know the green TRF has a finer grain then the white. The white is a bit too coarse to seal pinholes but maybe better then nothing. You may have to pick out bits of it between traces.

 

[ChildOfVision]

Thanks for link!
Yes, I know that the Green TRF is better, I intend to get it, but first I must find / make the appropriate paper! I always use scotch tape to clean the PCB after use of white TRF.

 

[evaine23]

you could try using a different printer or photocopier to see if the toner your using is somehow sensitive to the chemicals used during the etching process.

 

[ChildOfVision]

Yes, I could try it, if I manage to get to another printer! I had only bad experiences with a photocopiers.

 

[3v0]

Last I hear the only laser printers that had toner problems were some Brothers and some refilled cartridges.

 

[ChildOfVision]

Yes, Brother's toner has a much higher melting (and fusing) temperature. I am using Samsung ML-1640 (fusing temp = 180°C) with original cartridge on it. I think that the toner is OK, because many of my PCBs turned out well. I think the most important is the choice of the paper. It has to accept toner very well! Last paper I tried was some super-glossy inkjet paper. Paper got stuck to the copper and did not want to come off even after more than 6 hours! I am no longer wanted to wait, so I tore it by applying of brute force ! A lot of toner is broke away from PCB, but what left turned out perfectly with some bluish layer over toner without traces of paper and without pitting! (See my post about gummed paper at https://www.electro-tech-online.com/threads/diy-toner-transfer-paper-cheap-and-easy.94601/ (post#368)!)
PS: If anyone knows the settings for my printer (ML-1640) that gives the most of the toner let me know (I know to set economy-mode off, but what kind of paper to choose (plain, transparency, cardboard... I don't notice any differences!)?