I just finished up my new photo resist spinner.
Its consists of a plywood box 15" square and 3" high with a modified
surplus computer fan mounted in the center. I found a nice 4" Nidec
fan with a metal frame and cut off the plastic blades with my band saw.
Also took off about 1/2" of the metal frame to allow the fan hub
protrude above the frame. I used some JB-weld to glue a 6" aluminum
disk to the fan hub. I mounted a push button swithch in the side and
power it with a wall-wart transformer.
I posted a picture and a short video low quality video clip at: Spin
Coater <
http://picasaweb.google.com/cschaffter/DYIPCBs#>
The board is fastened to the aluminum plate with small loop of masking
tape. To coat the board I put about 1/8 tsp of the resist on the board
and spread it out with my small brush or my finger. This wets the
copper and prevents dry spots when spinning. Then I add another 1/8 tsp
in the center and turn on the spinner. I use the power button to
modulate the rpm and stop the process by eyeball.
I just started playing with the Genesis AQ3000 waterborn negative photo
resist and so far I like it. I am getting a nice even coating from the
spinner and after baking at 180 deg F the resist is nice and hard with
good adhesion. No worry about pulling off the resist with masking tape
while doing the second side. I have not etched a board yet but did a
test exposure yesterday with an old circuit negative. I think the
resist is quite sensitive, but I will know more when I get my UV box
built and receive my Stauffer 21 step test strip.
Next project will be to build the UV exposure box from a couple of 36W
nail polish curing units off ebay. UV lamp
<
http://stores.ebay.com/eTech-Digital-World__W0QQ_sidZ863785197?_nkw=36w\&submit=Search>
Craig
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