Cutting openings in brass?

[lab-dad]

That is GORGEOUS! I think I just wet my pants!
-Marty

[DaKra]

Superb bridge model, you have achieved about as near to perfection as one can hope to get in that scale.   I've also found the problem with commercial production is you have to balance perfection with ease of assembly.  The compromises can be painful.

Sounds like the etching company uses a plotter to print the lines. I guess they print directly on film, the plotting lays down enough ink to be light proof, as opposed to toner.   Just guessing though.

Since this has turned into a photo etching thread, I'm hoping we'll hear from Dan Pickard.  He posted a couple of photos of an etching work station he built, wondering how that's going now.

Dave

[John McGuyer]

For those who are just looking for a simple tool, don't forget nibblers. They usually require about a 1/2" hole, then you can nibble out whatever you want.

John

[finescalerr]

Thanks for getting us back on topic, Nephew John!

Let's start a separate photo etching thread if anybody has more to contribute. The results, as we have seen, can be stunning. One thing we should discuss on that thread is when photo etching is the best solution and when other, possibly more accessible methods (e.g., laser cutting), can work as well or better. Great subject. I want to learn more.

Russ

[JohnP]

Russ, I was thinking today when I get home I would apologize for the thread hijack. I got excited. Well, you know what I mean.

I have a manual nibbler and use it every so often, but I am glad it is still in the toolbox. It is cheap and handy tool that works on brass, aluminum and even light steel. It may wrinkle .005" thin stuff but works up to about .020". It requires a starter hole for blind areas but then can quickly open up straight lines with right angle corners so little clean up is needed. It's even a handy way to cut sheet stock down to size without using a saw.

So back to Ray--(still there?)-- what size opening and what thickness metal are you thinking of?

John

[Ray Dunakin]

Oh, I was just thinking it might be a better way to make window frames for my buildings... brass would be more durable.

[John McGuyer]

I too would like to learn more on photo etching. My only experience was when I was a factory pro racing R/C cars, I etched my own circuit boards and they were oh so crude.

John

[danpickard]

Gee Dave, thanks for dobbing me in...

Yes, have done a few home etch pieces, and after having a quick read through the thread, seems the technique I have been using (and what local professional etching guy has told me) is a bit different.  When it comes to the artwork side of things, CAD unfortunately does my head in, frustrates me too quickly trying to get simple things done, it does think like I think!  I ended up just using a free program called Inkscape, to essentially do a B&W positive/negative drawing of my items to etch.  I was able to use that program like I think, just drawing in the solid blocks of black to form the shapes or patterns I needed.  A few years ago there was an article in one of the Finescale Annuals about building an On3 Heisler which showed a page of the B&W artwork for etching it. 

Once my artwork is drawn (in my method, solid black is the resist layer and is what the brass piece will look like, white areas will be etched away by the ferric chloride), I have used a toner transfer paper put out by Pulsar ProFX.  I had read on different websites about using photo paper, or magazine paper as a transfer medium, which is not always successful due to the paper not realeasing the toner onto the brass.  The Pulsar Pro FX gear is designed to (and works well too) hold the toner image, use heat to transfer the image onto the brass sheet, and then once transfered to the brass, drop the brass straight into a water bath.  The toner transfer paper peels off very easily after about 30 sec.  Should note that the toner is "not set" on the transfer paper, and requires heat to fuse it to the brass.  Heat needs to be about 170 degrees celcius to fuse, so a cheap laminator doesn't get hot enough (only get to about 110 degrees), but there are laminators that have a variable heat setting (mine goes to 210 degrees, so works well.  I have found the toner transfer paper to work well beacause its a two part layering process, first the toner is transfered to the brass, then the toner is "sealed" with a foils layer.  The image transfer has seemed better than another method of a "Press and Peel" resist layer, because the toner and then foil are two thin layers (holds detail better), where as the P'n'P film is much the same principle, just both layers at once (ok for large solid etch shapes, but not as fine for say small lines of rivets etc).

More later...
Dan

[danpickard]

I should add that my commercial etching guy uses photoetching, which is about a 14-15 step process, which explains why etched material can be so expensive.  Artwork is first converted to the file he needs, then printed as a film (bromide maybe?), which can stay in storage as the master.  Brass is first well cleaned and then treated with light sensitive coating, then the film artwork used as mask as such when the brass is exposed under UV light, creating the resist layer, and then the brass needs to go into a developer to actually create the visible resist layer.  Eventually the brass sheet goes through a ferric chloride spray etch machine, and then cleaned of the resist layer at the end.  Not really a quick and easy process by any means...

I'll do some pics of my average home efforts in the near uture to show some of the results.  The issues I have at the minute are still with artwork alignment.  I can get away with that for one off pieces or test etches, but isn't reliable enough for long repetitive runs.

Dan

[JohnP]

Ray, if you can use even a simple CAD program you might want to investigate using a laser cutter person to cut plastic windows for you. I have a laser cutter guy who cuts my bridge master parts and mold plates for me. He can cut different thicknesses of a special, non-melting plastic used for indoor/outdoor signage. Google (sorry Russ) SketchUp could be used to draw the lines. I find the sign plastic to be very durable. It bonds using AC super glues.

John