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My first photo etch

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:

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

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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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Reply to
JazzMan
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you can buy the contents in a can and spray the board in a dark room and store them some where for drying. P.S. there is a shelf live for this chemical, keeping it in the fridge extends it.

Reply to
Jamie

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.

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Best Regards,
Mike
Reply to
Active8

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.

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Best Regards,
Mike
Reply to
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.

Reply to
Rex

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.

Reply to
Rex

In message , Rex writes

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............

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Clint Sharp
Reply to
Clint Sharp

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