Etching Toner Transfer

[Dylfish]

Hey guys

im trying to etch my first enclosure and everytime I try to use a laser toner transfer 1/3 usually peels off with it. im sure ive cleaned the enclosure well enough and ive given it enough heat. is there any tricks you guys use to get most to transfer properly? would putting it in a toaster oven for 20 mins after the ironing help with bonding, or is tht idea too fancifull?

Cheers Dylan

[ACS]

Could try roughing up the enclosure a bit first, to give the toner something more to bond to...  Steel wool, or maybe 800 grit??  Just a thought...

[Dylfish]

i was under the impression that it had to be sanded and smooth for a good bond. or am i completely wrong?  

[FisTheGoon]

Clean down the board with 3M scotchbrite or use 600-1000 grit sand paper along and across it.This  should help.
here a good video at the bottom of this site but no sanding is done.
http://thomaspfeifer.net/
click on Create PCBs with the direct toner method

[Dylfish]

ive been doing that but still no joy. anyone else had the same problem?

[Mark Hammer]

What are you using to transfer the toner to the chassis, PnP? photo paper?

[ianmgull]

ive been doing that but still no joy. anyone else had the same problem?

I've etched a ton of PCB's, but still have trouble etching enclosures. I think it's what somebody mentioned above though, I usually sand too smooth. I use photo paper and it peels right off no matter how much heat I apply.

[Mark Hammer]

I haven't attempted to etch aluminum boxes, but I think the issue is PnP vs paper.  The resolution of paper is certainly acceptable for chassis-etching, but the heat transfer properties are not.  You will want whatever allows the heat from the iron to be directly transfered to the toner as efficiently as possible.  It is basically a race against time.  The box sinks away the heat, so if the heat transfer is sluggish (as it will be with paper), the box tends to win the race.  If the transfer medium is thin and lets heat reach the toner quickly, you'll be in better shape.

[Dylfish]

yeah, just used magazine paper and normal a4 paper to test. normal a4 printer paper seems easier to rub off

[frank_p]

You could try an iron that can go higher in temperature if you are using thick photo paper.  The more the paper will be thick the more you have to jack up the temperature of the Iron.  Paper is an insulator and the amount of heat that is transfered by time unit is proportional to the heat coefficient of what is between your iron and your enclosure.  Like Mark say the more your paper is isolating the more you have to give heat per unit time to reach the desired temperature.  The heat that is transfered to your enclosure must be kept in the aluminium also: so the surfaces that are not heated give back the heat to the air: so no fresh air-wind around your box.

[davent]

If it all comes down to too quick a heat loss being the cause of problems, is there a way you could rig a hot air gun to blow from below into your enclosure so that when you go to iron on your transfer the enclosure is already hot and will remain that way until you're ready to shut things down?

dave

[Dylfish]

the enclosure is hot enough i beleive, just ask my burn marks

[Mark Hammer]

The enclosure is hot because it is conducting heat too efficiently away from where you apply the iron.