I'll post the instructions as I complete them to give you idea how everything goes together. As always, questions and comments are welcome.

Moderator: ArizonaBB39



DrPR wrote:Rusty,
Who does your photoetching?
Photofabrication Engineering
Talk to Karen Shapiro, Customer Service | 508.478.2025 x114 | kshapiro@photofabrication.com
What is the "formula" you use for the relationship between minimum line width and metal thickness. For minimum opening width and metal thickness?
It really depends on the company one uses for photo etching and thickness of the metal sheet used. Each company has their own "formula" because of the chemical mixture they use and brand of machinery they have. Karen can supply you with that information. Whichever photo etch company you use, they probably have a web site or flier with all the info you need to produce artwork for their company. Also, (if you have the money) they can do the artwork for you. Obviously, you don't require that.
I have tried several times to etch 1:96 catwalks for the smoke pipes of the Cleveland class cruiser, with no success. The bars that make up the walkway are 0.005" and the spaces between are 0.019" minimum. The failures have been caused by incomplete removal of the mask so one side of the catwalk etches perfectly and the other is etched incompletely. I have had no problem etching less detailed parts.
Unfortunately, home photo etching can do only so much. Your line spacing is correct for.005 brass. However, when the details get so fine and the spacing between the lines get so close, only PRECISELY mixed chemicals and computers PRECISELY timed to remove the parts from the etchant, can create the finished product you want. The catwalk screening is exactly what I am talking about. You need a commercial photo etcher to handle it. If the lines are even the slightest amount too close together, you will experience the problems you describe. Believe me, I know. I used to do home photo etching too.
I have attached an image. You can see the ladder-like catwalk deck - the black is the areas to be etched away.
Any suggestions?
Phil
















