Etching

[unittrain]

I have a question regarding etching, do you have to double side etch .01 and .005 brass? I'm using a basic set up, a small fish tank with an aquarium heater and a few airators to create bubbles. Most of the parts I have to etch are from 1/32 to 1/8" wide (that is the width of most of the parts). Thanks for any help.

[Chris333]

Do mean etch both sides at the same time? If you do it will etch quicker by half.

Just half etching is usually for when there is detail on just one side.

[unittrain]

Yes I'll be etching both sides all theway through I'm making a truss skeleton for another bridge so I figure I'll etch out an area about 1/16" wide around each column with some tabs here and there.

[Chris333]

Yeah I'd etch both sides just to save time in the tank, plus the edge would have to be a bit better that way as well. 

If you have an image for one side all you need to do is flip or reverse it for the other side.

[pnolan48]

Chris,

I'm think of getting into etching, as I understand the process quite well, though haven't done it. My one question is how do you make sure the two sides are in register? Make the mask the exact same size as the etched material? Drill holes for register marks?

[Chris333]

I lay one printed side down and tape it to the plexi. Then you lay the other side on that and tape it down. I just use a small magnifier to make sure they are lined up, but you could put crosshairs on the artworks if you want.


Once they are both lined up and taped to each other open it like a book and put the brass in there.

[unittrain]

I'm going to put crosshairs on my artwork, I'm just getting ready to do the solid hatching in CAD to get the darkend in areas that I want to etch away. Also another important thing is the exposure source I've read sunlight is really good but if you use artificial light it is best to go with shorter wavelength flourecent lighting. Does anybody here use flourecent lighting? If so do you have any suggestions on what to get?

[Chris333]

I have no idea what lights are best. I just use 2 100W bulbs:


Sometimes it might take 45 min. to expose enough, but walk outside and hold it toward the sun and it will take like 1-2min per side.  The light blue film will be a darker purple when it's done. Like this:


So if the sun is out just go out and get it done pretty much instantly. Me I usually work at night so sun won't work for me.

[pnolan48]

Thanks, Chris!

I knew it had to be simple, but my mind got stuck.

[unittrain]

Thanks for the insight.