Enclosure toner transfer failures - What could be wrong?

[lmorse]

Its a reasonably new box from China. I did sand and use polishing compound (forgot to mention that initially) so reasonably shiny for first attempt. But each subsequent attempt I've not used polishing compound. I've been using longer and longer ironing times on this one as each previous go failed.

[deadastronaut]

polishing?..

you really want it 'keyed' 220  grit wet n dry with a bit of soapy water and sand in one direction....not polished at all.

you can go to 600 after you etch it..to make it look buffed etc..

is your toner image 'thick' enough?...on very best quality print out.?.

[Pettol]

I have never had any success with photopaper or magazine paper. I'm limited to pnp blue. It's expensive, but works well. I suspect my iron doesn't get hot enough. I know for a fact that they differ quite a lot.  

[lmorse]

Everything is the same as my previous successful attempts: same iron, high print quality, enhanced blacks, same paper (plus others), etc. I only polished on the first attempt. Every other go I have sanded back with 220 grit. The only other variable I can think of is the box itself. I will have a go this morning with ironing for just 3-5 minutes.

[Pettol]

Well something's different or you wouldn't have a problem, right? 

[lmorse]

Interesting. I thought I'd try to transfer a PCB design onto a copper board as a sanity check. Transfer was great, however the toner scratches off with a fingernail (as easily as a scratch card for example). Does toner have a 'shelf-life'? Would you expect it to suddenly deteriorate? Last PCB and box I etched was about 5 weeks ago, and all was fine back then - I even cleaned off the paper with a plastic scourer, with no ill effect on the transfer. It's been hot and humid here lately (Australia). Would that effect toner life?