Etch An Enclosure Using Transparency Paper As Transfer (Like w/PCBs)?

[railhead]

Wow, that title ended up saying it all.

Anyway, I use overhead/transparency paper (film) when I'm making PCBs, going the ol' laser printer and iron route. I wanted to goof around with making an etched shell, but when I tried ironing the toner to the aluminum (which was almost mirror smooth), nothing happened. I cooked it until the shell got so hot I couldn't touch it, too.

My question, then, is whether or not this is even possible with overhead/transparency paper. Do you HAVE to use PnP for this? Should I have kept ironing for even longer?

TIA

[railhead]

Anyone? No one's done this? MarkM?

[GREEN FUZ]

As it`s possible to etch enclosures using the laser-paper method which is what I use for PCB`s I can`t think of a reason why Transparency paper wouldn`t work just as well.

Check this out.
http://modman.blogdrive.com/archive/27.html

[railhead]

Hm. I don't know what the deal was -- the transparency film was on the verge of melting everything was so hot, but nothing transferred at all.

I guess I need to try again.

[darron]

i've used projector transparency film to transfer to an enclosure. i printed some transfers which i was going to stick in the back of a box, and in frustration with pnp i grabbed one to see what it would do. it actually transfered! i was amazed and promptly printed up a layout that i actually wanted to etch. alas, with all of that black it never really worked properly again. it only transfered in large patches.

well that wasn't very helpful.... sorry.

[Paul Perry (Frostwave)]

It is difficult to iron PnP to an enclosure because of the enormous heat draw through the box.
But I was reading some Amateur Radio mags (lucky score at the thrift!) & one guy was making boards without ironing - he put the transparency paper (PnP substitute) on the PCB, then put 10 layers of newspaper each side, then a couple of blocks of wood, THEN A CLAMP, then PUT THE WHOLE LOT IN A TOASTER OVEN FOR 20 min or so!!!!!!

Well, I guess under those circumstances you could probably put a resist pattern on a potato!

he did say, best results take it apart when still warm but not quite warm enough to burn you.

[markm]

It is difficult to iron PnP to an enclosure because of the enormous heat draw through the box.

I disagree.
PNP will stick to aluminum just as well as it sticks to copper clad PCB as long as the surface is prep'd properly.
Surface prep seems to be the #1 failure of enclosure etching "mishaps" IMO.

[antojado]

I have no experience in this, but since I use them for other things (overheads  ) I know there are different types of films for transparencies depending on your printer. Maybe a different type would do what you need it to do?

[goldenechos]

I second the prepping bit...

I use a more diluted etchant. Before doing the toner transfer I do a quick etch of the surface.
I clean well with cool water and then Bon Ami.
Then I do toner transfer.
And finally the graphic etch.

Tony

[markm]

I use a more diluted etchant. Before doing the toner transfer I do a quick etch of the surface.

Just curious but, what is the reason for this?
The etchant corrodes the surface. 

[railhead]

I haven't had a second go with this yet, but my initial thought  was that the surface was too smooth for the transparency film. I got some PnP, but man, it'd be SO much easier (and cheaper) to use transparencies.

As far as prep goes, I ended with sanding the surface with 2000 grit, so it was highly polished and mirror-like. Was that too fine? I can see how the toner would need something to "grip" onto, and maybe I sanded things too smooth?

[Mark Hammer]

What hasn't been raised before is the distribution of heat in the heat source, relative to the sinking of heat by the thing you're ironing it to, and the melting point of the transfer medium.

Huh?

I suspect you'll find more success reported from folks transferring patterns to a 1590B, compared to a 1590BB or larger.  Why?  Because the smaller box can't dissipate as much heat from the iron, so more of the heat gets transferred to the PnP, glossy paper, or whatever it is you're using to get toner onto the chassis surface.  When the heat-source is broad and diffuse, like a clothes iron, transferring enough heat to overcome the dissipation properties of the box may end up applying too much heat to the sheet carrying the toner, and risk melting or corrupting it.  I suspect that if the heat-source used was more focussed (i.e., smaller than a clothes iron) you might be able to strike a reasonable balance between quickly getting enough heat to each specific part of the transfer sheet, and staying below the melting threshold.

Maybe the ideal is some sort of smaller heat-distribution surface that fits over a soldering tip.  I suppose one might fabricate a small (say 3/4" wide) piece of 12 gauge aluminum, with a 45-degree bend in the middle, and secure it to the chassis of a cheap 25W soldering iron using a bolt with the same thread as the soldering tip that normally fits in the iron.  naturally, you smooth all edges and the lower surface of the aluminum so it will slide easily.

Coming at it from a completely different direction, you will note that cast boxes are not exactly flawlessly level,  The edges and corners may sometimes be slightly raised, relative to the surface of the side and top panels themselves.  The result of that is that even when you get the surface buffed to a mirror shine, placing a clothes iron on it may result in more heat being transferred to the edges than to the middle of that surface because the raised edges keep the iron from fully pressing down on the transfer.  The suggestion arising from this is that maybe one needs to examine the areas you want to etch with a straight edge to see if the corners of the chassis are flat enough to allow even heat distribution, and file them down a bit if they aren't.  You will note that having a smaller heating source (as described above) will let you apply heat more selectively without having the chassis corners nudge the heat source out of the way that critical 5 mils or whatever.

[markm]

I haven't had a second go with this yet, but my initial thought  was that the surface was too smooth for the transparency film. I got some PnP, but man, it'd be SO much easier (and cheaper) to use transparencies.

As far as prep goes, I ended with sanding the surface with 2000 grit, so it was highly polished and mirror-like. Was that too fine? I can see how the toner would need something to "grip" onto, and maybe I sanded things too smooth?

2000 is much too smooth.
Just out of curiousity, has anyone in this thread besides me read this?

http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album24/

With some of the statements made in this thread......I have my doubts. 

Oh yeah, and this here is a DD enclosure......no heat issues here!
I don't really think size is an issue.
http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album23/FX_ad3208.jpg.html

[railhead]

2000 is much too smooth.
Just out of curiousity, has anyone in this thread besides me read this?

http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album24/

With some of the statements made in this thread......I have my doubts. 

Oh yeah, and this here is a DD enclosure......no heat issues here!
http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album23/FX_ad3208.jpg.html

Your thread is what got me started -- but you used PnP, and I wanted to use transparency film. Of course, you *did* say you only went up to 400 grit...

[markm]

Your thread is what got me started -- but you used PnP, and I wanted to use transparency film.

Why?

[railhead]

Your thread is what got me started -- but you used PnP, and I wanted to use transparency film.

Why?

Because I don't use PnP for my PCBs.

[sshrugg]

Transparency film sounds like a good thing to experiment with for PCBs, just because it could be cheaper.  I imagine you could clean it up with a paper towel with a dab of acetone and reuse the same sheet a few times!  For cases, though, I'd use the PnP just because I've had such consistant results with it.

Oh yeah, and this here is a DD enclosure......no heat issues here!
I don't really think size is an issue.
http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album23/FX_ad3208.jpg.html

That is sexy.  Nicely done, Mark!

[railhead]

I've had excellent results with transparency and PCBs. I print traces .6mm wide with pads 2mm, and everything comes out crystal clear and crisp. I haven't tried reusing the film, though, since I cut out the transfer -- but I'll have to try that tonight and see how it goes.

[Mark Hammer]

http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album24/
Oh yeah, and this here is a DD enclosure......no heat issues here!
I don't really think size is an issue.
http://www.aronnelson.com/gallery/v/MarkMs-Gallery/album23/FX_ad3208.jpg.html

Clearly, size doesn't have to be an issue, but I think few would deny that under some circumstances, it can be.
Just out of curiosity, a) what did you use to apply the transfer to that chassis, b) are the edges/corners as nicely finished to be level or lower than the main surface as they appear to be from that photo, and c) did you experience or do anything different in transferring that pattern than you normally would for a PCB?

[markm]

a) what did you use to apply the transfer to that chassis,

I used the same Sunbeam Iron that can be seen in the Tutorial. 

b) are the edges/corners as nicely finished to be level or lower than the main surface as they appear to be from that photo

Yes.
The top was thoroughly sanded FLAT as seen in the Tutorial.

c) did you experience or do anything different in transferring that pattern than you normally would for a PCB?

Actually, No.
I used the same heat setting, PNP, and painted on the additional mask areas.
This one was my first etch ever!