Homebrew PCBs

At 03:38 AM 11/18/2009, designer_craig wrote:
>
>
>FYI, Got a flyer from Michaels (craft store) and they had a product 
>called a YUDU for just north of $200 us. 
><http://www.whatdoyudu.com/products/default.aspx>http://www.whatdoyudu.com/products/default.aspx
>Its sort of an all in one unit for screen printing on T-shirts, but 
>I wonder if it could have any application on DYI pcb's

i owned a screen print business for almost 25 years and my guess is 
no, although i didn't look at the link. the mesh count for doing most 
t-shirts is dramatically courser than for hard surfaces like copper. 
plus it requires a special resist for the etchant. i did successfully 
screen print many PC boards for many years. here's a tip, write to 
Ulano (http://www.ulano.com/) on a letterhead requesting a sample of 
their "Ulano Blue Poly-2" film and they will send you enough to make 
several small boards. it requires a special 2-part developer and 
they  may supply that as well (ask for it). you can expose the 
between plate glass and black art paper under the blue poly with 
sunshine. do a test strip with pennies as art to find the exposure 
time. find a local screen printer of t-shirts and ask them for scrap 
fabric from when they make their screens. ask for a very fine fabric, 
about 300mesh (which they will have sometime for fine images) or so 
and stretch and staple it on a art canvas stretcher a few inches 
larger on each side than the board you want to print. then ask a sign 
printer for some enamel ink -- just a cup full will do plenty of 
boards. Naz Dar 
Co.http://docs.google.com/viewer?a=v&q=cache:nkPrDEZAsoYJ:www.nazdar.com/pdf/182034PC_Etch_Resist_Black_Rev%25202_022808.pdf+printed+circuit+etch+resist+ink&hl=en&gl=us&pid=bl&srcid=ADGEEShozL916Elmjj0JIiYDg56AO48v7T1sEk2aNEeapLIfDGFmvQ_oyz5zDRtw523fb9-5Wfgf0dmv0GsQptVLPYZ_FmQxebZvmkm6yOAIOxZGDQlqo0rCip4rydSTkrrKjLyl5l_Z&sig=AHIEtbT9WeoOYIloAnMDNsi1v2gB54Je8Q 
makes a pc resist ink that you can get in quart sizes (a lifetime 
supply). oops, now see it is gal size only. as i recall it was an 
alkaline reist ink? 
http://www.nazdar.com/prodDetail.asp?categoryID=0�ionID=0&subSectionID=0&subSection2ID=0&subSection3ID=0&attrCatID=0&attrIDs=0&searchtext=resist%20black&catID=&catTab=&productID=777

getting a good print is a bit of an art that requires practice. must 
print off-contact.  thin and clean up with mineral spirits.

but this is really only reasonable for the effort if you want to 
print multiple copies of the same artwork. then it pays off--can 
print hundreds for pennies a print.

huh. son-of-a-gun! we do leave an electronic footprint . . . i just 
googled and at http://www.answers.com/topic/circuit-board, in the 
periodicals sections of the biblio is a booklet i wrote back in the 
early 90s and sold with a kit. what a gas -- Alford, William. "Screen 
Printing PC Boards." Electronics Now, September 1993, pp. 38-41.


William Alford

GI Motility Medical Research Page
http://alford.grimtrojan.com/ 

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