Freerails Home 
Home Search search Menu menu Not logged in - Login | Register

Because of non-railroad abuse of the site, new members MUST use their first names (at least) to join NO EXCEPTIONS!

Etching for beginners
 Moderated by: W C Greene Page:    1  2  Next Page Last Page  
New Topic Reply Printer Friendly
 Rating:  Rating
AuthorPost
 Posted: Wed Jan 7th, 2015 07:43 pm
  PMQuoteReply
1st Post
Tramcar Trev
Registered


Joined: Sat Mar 16th, 2013
Location: Gordon ACT, Australia
Posts: 415
Status: 
Offline
Needed some plaques for the War Memorial and I used the iron on laser printer film, the dry iron on stuff; http://www.ebay.com.au/itm/151036912356?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649


The makers claim that 0.01mm lines are possible so I thought as the smallest line width I was working with is 0.25mm I should be ok. The brass sheet needs to be scrupulously clean, don’t use steel wool; rather a plastic scourer and maybe Ajax though I used “Gumption”. This gets the surface really clean and polished so you will be able to read the lettering on the background of duller etched brass. DO NOT BUY SECONDS (film) the sheets may be very cheap but also may have scratches on them which is a problem if you are doing fine work. Don’t rub your fingers over the surface to see how clean it is that will only mean starting over.


Printing the film went well with a little experimenting. The detail I wanted is well within the capability of the printer but large expanses of black around the object to be etched caused some problems, the printer didn’t like to print them on the film but it printed on paper quite well. Eventually by tweaking the printer settings it came out as well as I hoped, turn off the “toner saver”... The film is positive i.e. what you see is what is NOT ETCHED and what remains raised but as you have to print on the side of the film that is against the brass you have to print mirror image so that when viewed through the film you see what you will get. Mask out areas you don’t want etched with clear packing tape, it resists the heat of the etching process.


Application was a bit unfocused. I then used a sheet of plain paper between the iron and the film to stop minute movements. The iron temperature is critical but not that critical, I set mine halfway between “synthetic” and “wool”, as recommended. Iron the film on gently, let the heat and weight of the iron do the job, too much pressure can distort the image. Then you have to “quench” the sheet in cool water, I think the quick contraction helps release the film from the ironed on image.


Peel the film off and the next step as recommended is to go over the image with sticky tape. This cleans up the “furriness” around the detail and you can see quite a bit of fine blue lines coming away as well as the centres of filled letters which otherwise would not etch.


The etching itself I eventually did with ammonium persulphate. Mix it with demineralised hot water, make the water hot by putting it in a microwave in a plastic jug, I boiled mine and mixed it while it was very hot... While that was going on I had boiled the electric kettle as I needed to keep the etchant hot. I used a plastic esky as a “Baine Marie” to keep things hot. Do it outside with plenty of natural ventilation. Rubber gloves and goggles are a very good idea for mixing and using Ammonium Persulphate. The etching process took about 20 minutes and gave a depth of around 10 thou. Far quicker and cleaner than ferric chloride.... During etching I occasionally lifted the brass out of the tank and agitated the surface with a 1/2” paint brush, this removes fine specks of the mask and any remnants of adhesive from the sticky tape that would show as shiny spots on the finished job.


As I don’t have a guillotine (I must try and source a small one for cutting brass sheet) I cut the plaques from the sheet using an “Olfa Plastics Cutter” it has a very sharp hook type blade that was good for scoring half way through then its just a matter of folding on the scored line and the plaques come away cleanly, if you're clever you can achieve a bevelled edge...


The printed on mask is easiest cleaned off with some acetone rather than scrubbing with steel wool, (as recommended) steel wool will tend to polish the etched areas that you want to remain etched to imitate cast bronze. A couple of coats of automotive clear coat work well to keep it weatherproof and looking readable. Something I did not do with the earlier etched plaques.


The Photos show the finished job. I’m really pleased with the result the small print is quite legible despite being 1mm high and the “Fleur de Lis” came out well. I did want to use a “Rising Sun” and made the mistake of seeking permission, lets just say that after trying to “get through” to a bureaucrat trained to think in a 10Hz bandwidth I went with the Fleur de Lis..... Next time I'll buy a miniature “Rising Sun” from the War Memorial Gift shop and use that....


Despite my complete success with this job I'm going to make my Bandstand in “Federation” style timber rather than Victorian cast iron lace, to etch that much brass would require a lot of Ammonium persulphate. Etching like this to a decent depth uses a lot of etchant, the tank holds ½ litre and was exhausted after etching these plaques... I used about 2kg of ferric chloride to etch the trolley ears. I do have to make “Tram Stop” signs and they will be etched with an enamel infill....


In the past I used the photo resist film and the developing and etching technique using Ferric Chloride. That was very successful for etching my trolley ears out of 10thou brass sheet and was double sided work as the artwork was clear and could be seen through to align for exposure, Haven’t tried double sided work with this film but overall its so much simplified and some way of alignment would be possible.


I use a home made glass tank and an elcheapo aquarium pump for agitation, my local glass shoppe cut me some glass and I stuck it together with silicone $10 all up, and a $5 air pump from a $2 shop saw that sorted I already had some plastic tube.... You don’t need a lot of bubbles so leave Lloyd Bridges and Jacques Cousteau out of the equation but the wall of bubbles does need to be more or less even as just putting an air-stone in one corner will not give good results. I used a red hot needle to poke holes through the tube every 10mm and ran that across the bottom on one side and after some experimenting that seems to work.
Disposing of the depleted Ammonium Persulphate is a topic for hot debate. As I only have a small quantity I dilute and flush it...


Of course a CNC engraver would eliminate this technology entirely....

Attachment: DSCF1456.JPG (Downloaded 150 times)



____________________
There once was a man who said Damn!!
I perceive with regret that I am
A creature that moves
in predestinate groves
I'm not a Bus, I'm a tram
Back To Top

 Posted: Sun Jan 17th, 2016 09:36 pm
  PMQuoteReply
2nd Post
NevadaBlue
Registered


Joined: Mon Apr 7th, 2014
Location: Under The Blue Nevada Sky, Nevada USA
Posts: 701
Status: 
Offline
Trevor, this is amazing! Thanks for showing it to us. Very nice work!

Somehow I missed this thread. Hopefully it will be on top for a while now.

Last edited on Sun Jan 17th, 2016 09:37 pm by NevadaBlue



____________________
Ken

Back To Top

 Posted: Mon Jan 18th, 2016 01:08 am
  PMQuoteReply
3rd Post
Tramcar Trev
Registered


Joined: Sat Mar 16th, 2013
Location: Gordon ACT, Australia
Posts: 415
Status: 
Offline
Thanks Ken, saves a lot of money if yoy want to make builders plates, loco numbers etc....



____________________
There once was a man who said Damn!!
I perceive with regret that I am
A creature that moves
in predestinate groves
I'm not a Bus, I'm a tram
Back To Top

 Posted: Tue Jan 19th, 2016 02:00 pm
  PMQuoteReply
4th Post
NevadaBlue
Registered


Joined: Mon Apr 7th, 2014
Location: Under The Blue Nevada Sky, Nevada USA
Posts: 701
Status: 
Offline
I'm going to experiment. I ordered some transfer medium and some PCB chunks. Hopefully signs will be the result.



____________________
Ken

Back To Top

 Posted: Tue Jan 19th, 2016 10:14 pm
  PMQuoteReply
5th Post
Tramcar Trev
Registered


Joined: Sat Mar 16th, 2013
Location: Gordon ACT, Australia
Posts: 415
Status: 
Offline
We shall look for the signs... Using PCB you can make rather nice 1930's style illuminated signs with a warm white LED illuminationn behind the PCB....



____________________
There once was a man who said Damn!!
I perceive with regret that I am
A creature that moves
in predestinate groves
I'm not a Bus, I'm a tram
Back To Top

 Posted: Wed Jan 20th, 2016 03:54 pm
  PMQuoteReply
6th Post
Salada
Registered


Joined: Mon Nov 4th, 2013
Location:  
Posts: 1096
Status: 
Offline
Those Memorial Plaques are amazing !. So sharp & detailed. Well done !.

Regards,          Michael

Back To Top

 Posted: Wed Jan 20th, 2016 05:57 pm
  PMQuoteReply
7th Post
Tramcar Trev
Registered


Joined: Sat Mar 16th, 2013
Location: Gordon ACT, Australia
Posts: 415
Status: 
Offline
the lettering is about 1mm tall.... Used Ammonium persulphate to etch, ferric chloride was too slow and by the time I had the depth I wanted the Ferric had eaten away the mask.....



____________________
There once was a man who said Damn!!
I perceive with regret that I am
A creature that moves
in predestinate groves
I'm not a Bus, I'm a tram
Back To Top

 Posted: Wed Jan 20th, 2016 06:57 pm
  PMQuoteReply
8th Post
Salada
Registered


Joined: Mon Nov 4th, 2013
Location:  
Posts: 1096
Status: 
Offline
Aha !

I was wondering why you had used ammonium persulphate rather than ferric chloride - now we know. Thanks Trev.

Regards,              Michael

Back To Top

 Posted: Wed Jan 20th, 2016 10:07 pm
  PMQuoteReply
9th Post
Herb Kephart
Super Moderator


Joined: Thu Jul 19th, 2007
Location: Glen Mills, Pennsylvania USA
Posts: 6096
Status: 
Offline
OK, OK, So what's this amomia periscopes stuff called in the non-chemist world??

Herb



____________________
Fix it again, Mr Gates--it still works!"
Back To Top

 Posted: Wed Jan 20th, 2016 10:55 pm
  PMQuoteReply
10th Post
NevadaBlue
Registered


Joined: Mon Apr 7th, 2014
Location: Under The Blue Nevada Sky, Nevada USA
Posts: 701
Status: 
Offline
Thanks Trevor, for the tip on the etchant. I haven't ordered it yet. I was just in Salt Lake City and wanted to go to Radio Shack where they had the ferric chloride in stock but didn't make it over there. No worries, the PCB is coming from China so I have plenty of time. I'll order both the ferric chloride and ammonium persulphate from someplace.
I wonder if I could make signs like yours using copper sheet? I have a huge piece of copper sheet I could experiment with.
I was hoping for some neat effects with the PCB. I hadn't thought of back lighting. Interesting.



____________________
Ken

Back To Top


 Current time is 04:58 pm
Page:    1  2  Next Page Last Page  

Top



UltraBB 1.172 Copyright © 2007-2016 Data 1 Systems