Well, @Wolframore, a deal's a deal. I promised I'd open a new thread about this subject, and here it is. I hope it's worth your while.
You mentioned you've seen people make SMT stencils out of soda cans, and so I looked around using those keywords. And sure enough, I found a youtube video describing that technique and more.
The printed stencil ready to be press transferred onto the aluminum foil.
A successful transfer. With a few spotty imperfections here and there which I protected using a sharpie pen. It seems that transferring onto aluminum is not as easy as transferring onto copper.
Bubbling reaction ...
The stencil right after being etched.
Looking nice and clean.
I think I used too much soldering paste ... next time I won't be so wasteful.
This is probably the neatest, cleanest-looking SMT PCB I've ever assembled!
You mentioned you've seen people make SMT stencils out of soda cans, and so I looked around using those keywords. And sure enough, I found a youtube video describing that technique and more.
- The video recommends using aluminum from a soda can (I'd rather use aluminum from a beer can, though ) What I did is I measured the thickness of a soda can's aluminum, and it turned out to be 0.004". After a little browsing around, I found that Amazon sells #36 gauge aluminum foil (0.005" thick) which is normally used for arts and crafts at only $13.00 bucks apiece. Using this aluminum instead has the advantage of not having to remove the paint and plastic layers that soda cans normally have.
- I used a mix of muriatic acid and peroxide of one to three parts, just as the video suggested, but it took a lot longer than the couple of minutes that the video mentioned for the acid to completely eat through the foil... something in the order of 10 minutes or so. Also, I had to constantly move the piece around inside the container I used because the bubbles produced by the reaction tended to stick to the foil's surface. The bubbles interfered by preventing the reaction from continuing in an efficient manner. @jpanhalt, is there a particular reason for using said mix? Wouldn't using only muriatic acid be enough? Or is the peroxide there to prevent too fast a reaction?
- On a final note, I had some trouble with my laser printer. The paper I normally use with my transfer technique began to get stuck in the printer because its plastic film melted as it went through the fuser roll. It's very strange because it was working just fine... and all of a sudden this small disaster happened... So what I did is I began to experiment with different paper types. I even tried using the adhesive vinyl film (Con-Tact brand) recommended in the youtube video, but it didn't work as expected because the plastic gets distorted as it goes through the printer. In the end, I discovered that the perfect paper for this application is the vinyl film's back surface paper itself! ... it's a very thin sort of paper, so feeding it into the printer was a little tricky, but it all worked out when I decided to adhere a piece of masking tape to its front edge. That helped it remain straight and flat as it went into the printer.
The printed stencil ready to be press transferred onto the aluminum foil.
A successful transfer. With a few spotty imperfections here and there which I protected using a sharpie pen. It seems that transferring onto aluminum is not as easy as transferring onto copper.
Bubbling reaction ...
The stencil right after being etched.
Looking nice and clean.
I think I used too much soldering paste ... next time I won't be so wasteful.
This is probably the neatest, cleanest-looking SMT PCB I've ever assembled!
Last edited: