Etching brass?

[nachoman]

has anyone here ever considered brass etching as a tool for model building? While searching for information on PCboard etching I ran across this:

<!-- m --><a class="postlink" href="http://steampunkworkshop.com/electroetch.shtml">http://steampunkworkshop.com/electroetch.shtml</a><!-- m -->

I have etched copper clad PC boards before with great success. But I have been considering ways in which the technique could be used in model railroading. This could be useful for making brass detail parts such as grilles or even scratchbuilding locomotives out of brass. I am wondering if this technique could also be used to make a stamp or a stencil for applying logos on decal paper, or even spraying logos directly on rolling stock.

[Russ Bellinis]

I think it would have been the method of choice for some small flat details prior to the development of laser cutters. If you look at any laser cut brass kit, you could make the same thing by the etching process.

[Sumpter250]

I think it would have been the method of choice for some small flat details prior to the development of laser cutters. If you look at any laser cut brass kit, you could make the same thing by the etching process.

It is still the method of choice for after market dress up parts ("PE", or photo etched brass) for scale plastic warships, aircraft, and armor. There have been articles written over the years about photoetching parts. There are, of course, photoetched vent screens for diesels, and walkways etc. for rolling stock, in stainless, and brass.
The only caution here, is, you're working with acid, and possible toxic vapors. It's not a "kitchen table" project.

[nachoman]

for PC boards, the process is to laser print a negative of the design on glossy photo paper, lay the design down on the copper clad board, and iron the pattern onto the copper clad board. The heat from the iron will transfer the toner from the printed image to the copper board, and when submerged in the etchant solution, all will be etched except where the toner is. When I have done PC boards using this method, it reproduces details and fine lines quite well. I wonder if I could, for instance, take the a drawing of a tender with the rivet detail, iron the image onto brass, and etch it to leave the rivet detail raised above the rest of the brass.

[doctorwayne]

I wonder if I could, for instance, take the a drawing of a tender with the rivet detail, iron the image onto brass, and etch it to leave the rivet detail raised above the rest of the brass.

It should work, or you could try these. A little on the pricey side, but I've already got some projects in mind.

Wayne

[jim currie]

I wonder if I could, for instance, take the a drawing of a tender with the rivet detail, iron the image onto brass, and etch it to leave the rivet detail raised above the rest of the brass.

not to rain on your parade but have done a bit of PE and rivet detail would be very hard as in etching you have undercutting and the more material removed the more the undercutting occurs also if you look at a etched edge it is not square .it more resembles a slightly concave edge whitch would be ok if you wanted to have square headed rivets.
jim

[Sumpter250]

It should work, or you could try these. A little on the pricey side, but I've already got some projects in mind.
Wayne

I've seen these surface detail sheets at an AMPS (armor models) show. These would be far easier than trying to etch, and probably no more expensive. As I recall, they are resin on decal film, and they seem to be very popular with the Armor modeling folk.

[boppa]

for PC boards, the process is to laser print a negative of the design on glossy photo paper, lay the design down on the copper clad board, and iron the pattern onto the copper clad board. The heat from the iron will transfer the toner from the printed image to the copper board, and when submerged in the etchant solution, all will be etched except where the toner is. When I have done PC boards using this method, it reproduces details and fine lines quite well. I wonder if I could, for instance, take the a drawing of a tender with the rivet detail, iron the image onto brass, and etch it to leave the rivet detail raised above the rest of the brass.

this is something I have had a lot of experience with (copper etching- not brass)

HEAT TRANSFER (photo) etching as described above is the most accurate way of etching (to within 0.1mm accuracy easily or better with copper, brass should be just as acurate)
I have handmade PCB's with 0.25 mm wide tracks with 0.1mm spacing from a laser printer and `iron on' ie heat transfer prints with a better than 50% success rating

photoetch is WAY more easy and more importantly accurate than heat transfer etching, and more importantly it has less `blurring' if you can time it

hardest part is that both methods require etching times- and they depend on acid strength, time, heat and the angle you hold your head at....

(seriously- its almost `black magic' etching stuff- a good etcher can do `magic' a bad one can't..- you have to `know' just when to pull it from the acid for accurate results)

EDIT TO CHANGE PHOTO TO HEAT TRANSFER

(2 different ways and heat transfer is less accurate than photoresist methods)

undercuts etc sound like poorly applied (ie unclean surfaces) and overlong etching times...

[boppa]

actually what he is describing is heat transfer `iron ons' which are quite accurate (but as I can say from personal experience- less than perfectly accurate)

photoresist is much more accurate

(I can post the results of a heat transfer pcb shortly as soon as I find my cameras usb cord..)

its what i used with `mostly good' results, but a photoresist etch is MUCH MUCH better

and the etching time is equally (actually much more)important- in fact I would say that the etching is 99% of the accuracy-

under and overcuts are the result of blurring (via printing method)
and etching (time)

[Dave Harris sctchbld]

I wonder if I could, for instance, take the a drawing of a tender with the rivet detail, iron the image onto brass, and etch it to leave the rivet detail raised above the rest of the brass.

not to rain on your parade but have done a bit of PE and rivet detail would be very hard as in etching you have undercutting and the more material removed the more the undercutting occurs also if you look at a etched edge it is not square .it more resembles a slightly concave edge whitch would be ok if you wanted to have square headed rivets.
jim

Here are a few shots of a scratch built tender I built to test photo etching techniques I had read about.
I had Kinkos photo copy on clear acetate the sides of a Riverossi Y6B tender to get the rivet & panel line detail . When I asked them to copy it , The clerk rather curtly told me " This aint star trek, we don't have a replicator" ! Took some convincing to get him to do what I wanted , but I was trying to do it without having to do a lot of art work. Never had any complaints about how the rivets turned out --- BUT I don't let "Rivet Counters" in the house!

One word of caution, if you are going to try photo etching , be aware that you NEED a good respirator to avoid the Zylene fumes, they are NASTY! I was only exposed to them for abour 3 minutes ( with out protection because I did not know I needed it) & got a violent headache that lasted for hours. Research on Zylene showed that it causes severe brain damage with prolonged exposure. BE Careful!!