Felix has put together the ‘definitive tutorial’ on making solder paste stencils out of soda cans, who am I to argue with that ? Looking at his previous attempts to perfect the process I can buy that.
The soda can appears to be just the right thickness (and price) for a sharp stable stencil. Felix uses the toner transfer method to etch the holes in the soda can using readily available chemicals. If you’ve ever etched a circut board it’s a similar process.
The write-up is here.
If you make it that far, you’ll want to check out Felix’s solution for a cheap manual pick and place that he put together for $20. Just add a home made reflow oven or hot plate and you’re making your own surface mount boards in no time.