Brass etching

Not too sure why but i have seen a number of vintage cars where the owner has stuck Dyno labels on the instrument panel advising what the various switches do. Personally I think that is a bit naff and is hardly a period feature. So I have been looking into something more in keeping with the period – I thought custom built brass plaques should do the job, i.e. etched brass labelling. Historically, coach builders always placed a small brass plaque onto the engine bulkhead somewhere advertising that it was themselves that created the automotive art. But naturally *my* coach builders were not in business in the 1930’s so I will just have to create something using their logo and then ‘age’ it.

Brass etching has been around since the middle ages and was used in the early days of printing, so the basic technique is well documented – all you need is a liquid to mask what you want to keep and some form of acid to cut away the unprotected areas. Readers of my other blog will know that i like a bit of alchemy AND it is artistic so right up my street so to speak. Leaving the treated brass in the acid for a length of time results in the protected areas being higher than the etched surface. So the whole item can be sprayed with paint and the high points lightly sanded, removing the paint leaving you with… a plaque with a professional design and nicely defined lettering.

I am in discussion with the Artisans about redesigning their website for them and as part of that task I have taken the opportunity to recreate their logo in the form of a vector graphic because it can be resized from tiny up to ‘huge’ with no loss of image quality. We are agreed that my version will be their new logo. So, within photoshop, I copied the image onto a rectangular plaque shape, added the company name plus the place of origin in period style text and added a shoulder for the screw holes. This looked pleasing so I now have the ‘plaque’ image that can be transferred to brass ready for etching. The orange areas are a feeble attempt to see what it would look like with ‘aged’ brass showing against the black background.
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These days, you can create the mask with a sharpie pen and use Ferric Chloride as ‘the acid’. This is often used to create prototype printed circuit boards where you can literally draw the lines of the circuit that you want and let the acid remove everything else. The acid does not eat the permanent ink of the sharpie pen so this is fine for a test piece as I don’t really want a hand-drawn image, I want it to look more professional. So I am modernising the technique and using Photoshop for the image and a laser jet printer. Sadly 2mm brass sheet won’t feed through my printer so somehow I need to print the design on paper and then use heat again to transfer the design off the paper and onto the brass. A laser-jet printer is needed because it uses toner (not ink) which it fixes to the paper using heat.

Question is what sort of paper will best release the toner when I heat it up again?

Second question is how to apply heat to the paper and brass plate… using a domestic iron is the idea but I suspect borrowing the household iron would be frowned upon so I bought a £6 steam iron from a high street shop to do the job. Theoretically all I need to do is place the printed image face down into the brass plate then heat the paper and brass with the iron – the heat melts the toner which then transfers from the paper to the brass… “Aha”, i hear you say as you begin to see my cunning plan.

Question two being resolved, i moved back to question one – the paper. Printer paper is designed to hold ink (and toner) so I know I can create a finely detailed design but what  paper is the best to use?

  • Attempt 1 – ordinary printer paper – applied heat – but it pulled all the toner off the brass when i peeled away the paper. Clean brass and start again.
  • Attempt 2 – ordinary printer paper – applied heat for 5 minutes – same as above
  • Attempt 3 – ordinary printer paper – applied heat for 10 minutes – put brass in water to make peeling the paper away easier – it took multiple soaks before the paper would fall off the brass – image was better but definitely not good enough
     photo IMG_2839_zpsufqtcp9e.jpg
  • Attempt 4 – intraweb suggestions imply the paper in free Sunday newspaper magazines is thin enough to soak off easily and is free…
  • I should have mentioned… the printing image in the photo below is reversed (a negative) so that when it is transferred onto the brass it is the right way round – this may seem obvious (and it was – the second time) photo IMG_2840_zpsjutcfknv.jpg
  • I had high hopes for attempt 5 – and indeed the paper DID peel off easier but it was STILL holding onto too much ink – AND sadly some of the magazine ink came off with it creating a ghost image
  •  photo IMG_2842_zps3evcd1ib.jpg
  • Attempt 6 – i tried overhead projector slide (plastic) – this deposited all the ink onto the brass BUT i noticed it moved under the iron and smudged the ink. Possible technique but there is still room for improvement
  • Attempt 7 – will be proper paper designed for transferring circuit board designs onto brass – cheaply available on fleabay – i await the delivery… ho hum

In the mean time lets try some etching because if i can’t get that to work then getting the design onto brass is a moot point… so much to learn when building a car!

Ferric chloride is available on the interweb or from electrical component stores like Maplin (other stores are available). In crystal form this is only a couple of uk pounds and is mixed with water to make up the solution. I carefully read all the paperwork that came with it as this is ‘acid’ but not particularly nasty stuff when used in a ventilated area. The intraweb suggested heating the acid to 30 degrees to speed up the process – never one to believe everything i read and seeing as i can spare the time I thought I won’t heat it up at all and we will see what happens.

Etching attempt 1 – I cut a small scrap piece of 2mm which brass and wrote on it with a sharpie pen – then dropped the plate into the solution for 10 minutes. The liquid is dark so you can’t see what happens but i envisaged 10 minutes should be safe – i also read that it was better to move the acid about so that ‘fresh’ acid was always coming into play on the brass… so after 10 minutes and wearing protective rubber gloves, i removed the first test piece. It HAD etched the unprotected areas but not by much maybe 0.1mm (if that). Thats only just about enough to be able to sand the high areas… i think it needs longer.
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Etching attempt 2 – Same process as about but left to soak in the acid for 1 hour with acid agitation every 15 minutes. Much better with a noticeably more pronounced raised image but still not good enough. Leaving it to soak for several hours is a bit boring so I think i understand why people heat up the acid. (memo to self – I really must learn to believe advice). Luckily from my days of doing my own nickel plating, i have an aquarium heater that will suit the job nicely, add in my plating aquarium bubble maker and i have automated liquid agitation too… its funny how a simple theory ends up being another feat of engineering… something for another day… here is what attempt 2 looked like:
 photo IMG_2843_zpsrcgt1sra.jpg

In the image about you can see the lettering is raised up. I took very little care with sanding the paint off this area as this is only a test piece but it did work and the writing  was nice shiny brass. I then dropped the piece into my antiquing solution to ‘age’ the brass and you can see the end result – I think this is going to work, the test piece looks like it has had a long and hard life. I have high hopes for producing what i was hoping for, time and practice will get me there…

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