[TriEmbed] DIY Metal solder paste stencil for SMD

[Jon Wolfe]

Very neat! And scary! Any ChemE know of an alternative to HCl? Supposedly, for etching copper, you can use vinegar (and a lot of extra patience), and it's about the safest way to etch, and probably makes watching paint dry look fun. It would seem to me that aluminum might be a little pickier than copper though.

Not being experienced with solder masking, what's the advantage of this over a plastic mask? Just durability?


Also, you can find aluminum flashing at Lowes in the roofing/gutter section that has a similar consistency to soda cans. I don't know how well it would work for a mask, but I know first hand that it works well with toner-transfers, I used it to make the capacitive touch buttons on this:

http://bytecruft.blogspot.com/2011/03/good-times-part-1.html

It's been so long that I don't remember the prep work that I had to do, but it wasn't much. I think there is a slight coating, but I think it''s less than a typical soda can.


Also, the aluminum flashing mills pretty well on my CNC, I just never tried to do something so small and precise as what you would need for a mask. I also don't know what long term effect that has on the expensive end mills, so I've kept it limited. I'm sure it dulls them faster than the MDF or PVC I usually use. But that could potentially be much safer and faster than the toner transfer.




________________________________
 From: Pete Soper <pete at soper.us>
To: triembed at triembed.org 
Sent: Tuesday, May 6, 2014 6:32 PM
Subject: Re: [TriEmbed] DIY Metal solder paste stencil for SMD
 


Fascinating. 

I'd like to add one additional warning about those chemicals. Acetone will ignite at twice the air/fuel ratio of gasoline and it's very volatile, so at higher temps like described in that how-to it might be possible to set yourself up for something extremely unpleasant with an open flame or spark in the vicinity. A very, very good mask would be a given, of course. But the hydrochloric acid/peroxide mixture made my hair stand on end.  I didn't read must past that, so I don't know if they call for heating that mixture...

Around age 11-12 I  was casting zinc/sulfur solid rocket propellant
    and doing other insanely dangerous things. But now days after
    reading this the hundred dollars for a stainless steel stencil seems
    completely reasonable. :-)

-Pete



On 05/06/2014 04:02 PM, Shane Trent wrote:

Pete, 
>
>
>Here is the article I mentioned last night about making metal paste stencils. I do not recall if this has been posted here so I thought I would post it. I am enjoying many of the projects at LowPowerLab. 
>
>
>http://lowpowerlab.com/blog/2013/02/11/diy-smd-metal-stencils-the-definitive-tutorial/
>
>
>
>Shane
>
>
>_______________________________________________
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