On Tue, 14 May 2002, Pic Dude wrote:

>Peter's got the right solution here.

Actually Dwayne Ried (?) had the L posting, I just explained it.

I seldom use the L, I use taped foils and double glass exposure frame. The
alignment is aided by putting fiducials OUTSIDE the board and by tacking
one of the foils to a corner of the board with a tiny bit of blu-tack or
hot glue (only one side). Once I close the glass frame, I do not open it
anymore until both sides are exposed. I expose one side then the other. No
black carton is used on the 'other' side, but the exposure table is black.
Side light to the lower layer never was a problem for me. The fiducials
outside the board allow perfect alignment without fudging with the board.
I often make small prototypes that have real funny shapes so I make them
from copper clad and spray photoresist on them after I cut them to shape.
This is a pain but the board house would bankrupt me for the 3-4 tries I
need to get everything right (see Tal's posting for prices around here).
Resist board cannot be cut without chipping the resist, even though I use
a jeweller's saw with 000 blades that cost a fortune each.

Peter

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