My first photo etch

[JazzMan]

I've used various processes in the past to make boards including
hand-drawn resist, laser transfer paper, and an odd technique of
printing the reverse image on a peeled backing sheet of labels
and ironing the toner onto the board. Results were ok, but I
wanted to try the photographic process. Being too cheap to buy
the light source I dug out my 25 year old fluorescent desk
lamp with two 18" tubes. I didn't know how long to expose the
board so I drew up a test image with the intention of using
a light shield to vary the exposure along the length of the
strip. Here's the result:

http://www.fierocentral.com/images/misc/firstetch2.jpg

The leftmost part was exposed for 5 minutes, going to
the right in decreasing 30 second increments. Here's a closeup:

http://www.fierocentral.com/images/misc/firstetch.jpg

The numbers are upside down, BTW.

The narrowest horizontal lines are 0.025" and the narrowest gap is
0.0045". This was soooo easy! I don't think I'll go back to the
old ways except for quick and dirty projects. The only downside
is the cost of presensitized boards, they're fairly expensive.

Anyway, just wanted to throw this out there.

JazzMan
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[Active8]

On Sun, 20 Mar 2005 23:19:53 -0600, JazzMan wrote:

is the cost of presensitized boards, they're fairly expensive.

You might look at think and tinker's dry-film. You can probably get
a wal-mart laminator to apply it, but I've only checked the temp on
my unit, so the jury's still out as to what modifications I'd need.

www.thinktink.com ??

 

[Rex]

On Sun, 20 Mar 2005 23:19:53 -0600, JazzMan wrote:



You might look at think and tinker's dry-film. You can probably get
a wal-mart laminator to apply it, but I've only checked the temp on
my unit, so the jury's still out as to what modifications I'd need.

www.thinktink.com ??
--

I think the hard part is finding a cheap laminator that will accept the
thickness of a PCB. I tried this a few years ago and never got
dependable laminations of the dry film with the cheap laminator I tried
to use.

 

[Active8]

I think the hard part is finding a cheap laminator that will accept the
thickness of a PCB. I tried this a few years ago and never got
dependable laminations of the dry film with the cheap laminator I tried
to use.

What was the symptom? Did it mash your dryfilm? I ran a toner
transfer through it a couple of times and it worked. I think slowing
it down would allow me to do it in a single run. IIRC the laminators
sold for dry film apply pressure but don't remember how much.

 

[Rex]

What was the symptom? Did it mash your dryfilm? I ran a toner
transfer through it a couple of times and it worked. I think slowing
it down would allow me to do it in a single run. IIRC the laminators
sold for dry film apply pressure but don't remember how much.

At the time I think the cheapest ThinkTink laminator was over $300. I
bought a much cheaper one from a local office supply but it was not
designed to accept .031 thickness. I opened up the case and made some
mechanical mods to let it open up a bit wider. There were some screws to
adjust tension which I also made externally accessable.

As I recall, with mine, the laminate had kind of a wavy quality.
Probably uneven heat or pressure. The one I had did not have heated
rollers either -- it had a heating strip.

Bottom line... you get what you pay for and I tried to go cheap. Hard to
tell the mechanics of a laminator without opening it up and I think it
matters a lot for this application.

 

[Clint Sharp]

Bottom line... you get what you pay for and I tried to go cheap. Hard to
tell the mechanics of a laminator without opening it up and I think it
matters a lot for this application.

How 'bout the fuser assembly from an old laser printer? Should be
possible to buy a refurb assembly for an old Laserjet II,III or IV for
little money. The temperature would need controlling and you'd have to
drive it but............