Toner transfer - Difference between copper and aluminum

[Hemmel]

Hi guys

Yesterday I tried to etch an enclosure using the same technique I used to successfully etch 3 PCBs. So I started with printing a negative of what I want on the enclosure (I forgot to "mirror" it though...) on magasine paper while the enclosure was being pre-heated under the iron. Then I carefully placed the printout on the enclosure, checking if it fit, and just to be sure I left it 6 minutes instead of 4 (4 minutes for successful toner transfer on my copper boards). I carefully lifted the magasine paper and saw that there was only a greyish shadow of the toner image on the enclosure.

I was afraid of leaving the iron on the enclosure for a longer period, as I didn't want to warp or damage the enclosure.

I read a few threads that cover enclosure etching but there doesn't seem to be much info on toner transfer, except for "do the same as copper PCBs". I was wondering : could I have left the iron for longer than say 10 minutes without damaging the enclosure ? Do I have to leave it longer on aluminum than on copper ?

Thanks !

[GoranP]

you won't damage the enclosure. as for the toner transfer, i never got one to stick properly. my hunch is that the enclosure being a heatsink is messing with the temperature of the toner. just a wild guess.
otoh, the few successful etches i did were all using pnp blue. iffy results as well but good enough.
people get great results with toner transfer, i was never able to.

[Hemmel]

the few successful etches i did were all using pnp blue.

Yeah.... I'm going to buy a few from smallbear and test it out.
Also, I'm going to try to leave the iron for a longer period tonight. Maybe even use parchment paper instead of magasine...

[pakrat]

Slade has a great tutorial on etching and it's hard to argue with his results: http://www.diystompboxes.com/smfforum/index.php?topic=80962.0
I have had great results with glossy magazine paper and I don't preheat the enclosure. I put the transfer on the enclosure and then put the iron on and let it heat to temp. Then use a lot of pressure while ironing it on. It takes usually 5 to 10 min to get a good transfer.

[Arcane Analog]

Preheating the enclosure is a bad idea and unnecessary. If you do not lay it down perfectly the first time you may not be able to reposition the transfer.

[Hemmel]

I preheated the 3 PCBs I successfully etched, so I thought I had to do the same to transfer toner on the aluminum enclosure. However, since it's a different metal, I'll try something else.

I'll have a look at Slade's tutorial, thanks pakrat !

[garcho]

+1 @ do not preheat. Maybe on your thousandth enclosure...

I use PnP blue, I get it directly from the company, I don't preheat, I do sand it down with 100 grit so it's flat but not too smooth, I use a Brother laser printer (I've heard bad things about their toner but it works just fine for me), I mask the toner with oil paint markers except for the detail, I let the iron sit on it for at least 10 minutes, and I run it under cold water before peeling. I get pretty good results with most issues being rooted in not sanding properly, impatience, not masking enough, etc.
I also etch my drill guides (I do the graphics on Inkscape) so I don't have to make a drill template.

[Hemmel]

Those look amazing...
I espcially like the Tone Bender with the lightplate. Sweet !

Can't wait to do my own !

[pakrat]

Yes, very nice boxes Gary.

[Arcane Analog]

I am not a big fan of PNP. It is very expensive, not very durable (more prone to bleed through or heat damage) and you cannot get as much detail as you can with cheap photo paper - the stuff Slade uses.

I could never get 'shading' and fine detail to work very well with PNP.

[seedlings]

^Those are b'etch'n boxes!

CHAD

[garcho]

Thanks for the kind words dudes! Don't look too close. 

@Arcane   Gorgeous work! I had the PnP from PCB transfers and that's how I started with etching the enclosures, I'll definitely give the Slade method a look see. I dig his reverse etches, too.

[Arcane Analog]

+1 on using the the etch art for drilling template. It will save you the trouble of measuring and/or making a template later.

[PRR]

> tried to etch an enclosure using the same technique I used to successfully etch 3 PCBs

It's not the different metal. (Al sucks 3 times the heat per gram, but is about 1/3rd the grams of Cu, so the heat is similar for similar size/thickness.)

It's the thickness.

And the sides.

The copper is, what, 0.010" thick? And the box is, say, 0.100" thick? That's *10 times* the volume of metal.

Think of drilling. When drilling PCB, the copper is holy instantly, most of the time is chewing board-stuff. OTOH drilling the box takes significant time. It's just a bigger job.

And when you try to heat the top, the sides suck the heat away.

So time-based assumptions are poor guidance.

I dunno what the answer is. I do wonder if an infrared thermometer might be helpful, to know how-hot it is without a lot of finger-burns. If you are very clever, you may be able to skirt AA's warning. Bring the box up just-short of the sticking-point, lay, adjust, then come up another 20 degrees with the iron.

[Hemmel]

Actually I used pakrat's advice yesterday evening.
I printed the image (mirror and negative this time) and delicately placed it on a cold enclosure (sanded and acetone-cleaned). And made sure the image was straight.
Then I put the iron at setting 3/10 on it. I left a large part on unprinted paper on one side, so I could see if the paper moved while setting the iron.
After about 2-3 minutes I checked to see if the toner started to stick and it did. So I boosted the iron to setting 10/10 and applied pressure for about 5 minutes.

Unfortunately some letters were a bit blurred. But the toner transferred very well this time. I'll try it again tonight. As for the blurred letters, well that seems to be a problem with my printer since I tried to print the image again, and already the smaller letters were blurred on the paper. I'll try a different font.

[Hemmel]

Well.... not quite completely satisfied...

I guess I left the enclosure in the acid too long. I bubbled like crazy and even ate through some of the toner...



I tried sanding and sanding but gave up...

[garcho]

I guess I left the enclosure in the acid too long.

You got it. I just made the same mistake. Multitasking, and next thing I know... 

[mremic01]

For enclosures, I've found that using more toner seems to work better, while less toner works better on copper clad. At least I assume this is what the 'thick paper' setting for my printer controls. I use Walgreen's brand glossy photo paper made for inkjets with a Brother laser printer. The toner doesn't fuse to the glossy side properly. Other brands of paper have not worked well. I also use generic cheapo toner cartridges from China. The Brother brand cartridges use toner that doesn't transfer anywhere nearly as well. I find that prepping copper by cleaning it with a little toothepaste helps. The toothpaste is abrasive enough to get it clean, but not so abrasive that it scratches it up like steel wool. Then I wash it with dishsoap and give it a quick once over with acetone, and the transfer usually goes well. I do the same thing with the enclosures, but use steel wool instead of toothpaste, just because the steel wool doesn't scratch up the alluminum like it does copper, but toothpaste works just as well.

I get the best etches on alluminum if I occasionally brush it with a toothbrush under cold water. Once I can see that there etch part is lower when the acid is washed away, making a depression in the metal, it's done. Any more time and the etch starts to get messy.

[Hemmel]

Maybe it's because I used Muriatic Acid and Peroxyde instead of Ferric Chloride ?
Is it not recommended for aluminum ?

[Govmnt_Lacky]

I am not the absolute BEST source of information about enclosure etching BUT....

I did successfully etch aluminum plates for enclosures. One piece of advise I can recommend...

Ditch the acid bath and go with using a Q-tip to dab the acid onto the spots you want etched. It allows finer control, less use of product, and you dont subject the parts you DONT want etched to the acid.