Seeking photoetch advice

[PJPickard]

Hi all,

Working on designing/drawing my first photoetch parts. Planning on using PPD based on advice from here and other forums.
Can anyone help on sizing? For example if I have a window opening and want it to fit a plastic window, how much bigger do I make the opening? For arguments sake lets say the window is .2" x .25". Will the undercutting that is part of the etching process allow the window to drop in if I draw the opening exactly .2 x .25"? Or does it need to be a couple of thou bigger?

Next question:
For car siding, what have others found to be a good width of the grooves?

Thanks guys and happy new year!

Paul

[Sokramiketes]

It's based on the thickness.

Read up here:
http://www.hollywoodfoundry.com/HowToPapers.shtm

Scroll down to the series on metal etching.

[PJPickard]

Wow thanks for that, I had not come across it before, excellent guide!

Paul

[Sokramiketes]

It's the best overall guide I've read.  It's worth passing on.