Question for those who’ve made their own photoetch

[OldNYJim]

So, I’ve read about every topic I can find on here about DIY photoetch, and I’ve had an idea brewing in my mind for a while...and I guess I’d like to know from someone more knowledgable than me why it WOULDN’T work.

I have a Silhouette scrapbook cutter here, and it occurred to me that I could maybe cut “masks” from signwriting vinyl, apply them to some brass/copper/aluminum sheet and use an appropriate etching fluid or acid to make my own metal parts

Without going any further with my experiments, is my theory sound at least?  If amateur electronics makers use a Sharpie or similar do mark out the parts of a PCB they don’t want etched I figure this might be a quick and easy way for anyone else with one of these scrapbook cutters to make some cool stuff!

[peteski]

Sharpie works very poorly as etch-resist pen.  I've tried it.

Your idea has merit, if the adhesive will stick well enough to the metal to prevent any of the liquid etchant from getting in between the adhesive and metal.  I would compare it to masking and airbrushing multiple colors on a model car body.  If the masking tape edge is not burnished perfectly, the paint will bleed under it.

Other than that, it should work.  The vinyl and pressure sensitive adhesive on it should easily withstand contact with the etchant.  Make sure the metal surface is smooth, clean, and grease free.  I clean the copper and brass I etch using household copper cleaner. It cleans using both, gentle abrasive, and chemical action.

Edited March 5, 2020 by peteski

[OldNYJim]

Interesting!  Thank you so much for your feedback!  Guess I need to get some material and enchant and try this out!

[kitbash1]

  On 3/5/2020 at 4:34 AM, CabDriver said:

Interesting!  Thank you so much for your feedback!  Guess I need to get some material and enchant and try this out!

Expand  

All you'll do is make a big toxic mess. The metal plates that are used for PE parts are like printing plates. They are coated with chemicals that must be exsposed to a light sorce to burn an image on the coated surface. Then you process the plate in an acid solution for a period of time to eat away the areas around the burned in image. And then you have to dip the PE in a fixing solution and then wash the part in water.  Also have you figured out how your going to dispose the waste chemicals ? Because you just can't dump them down the kitchen sink. You Tube has some tutorials on this subject. 

[OldNYJim]

I understand how the “photo” part of photo-etching is done - I’m trying to figure out if you can use a cut vinyl graphic as the resist instead.  

What would happen to make a “toxic mess”?

 

[Flat32]

Etchant is usually ferric chloride and if it doesn't affect the vinyl adhesive it should work.  The ferric chloride is available premixed on Amazon and has relatively safe disposal methods. I bought all the stuff to do dry transfers using laser printed images on transfer paper and heat pressing onto the brass.

[Russell C]

Having worked several years in the graphics department at PMA Photometals, which did both ferric chloride etching of brass, stainless steel & copper sheet, and nitric acid etching of zinc braille dot signs, I can say firsthand that the nitric acid was a nightmare for the owners to deal with, while the ferric chloride was easier, and could be replenished and used again after straining the waste out of it. But to do top-quality etching, they used professional grade photoresistant film applied to the sheet material via a machine for that task. When the photoresist didn't stick right, that produced lots of parts that went straight into the scrap barrels. Additionally, there was a specific "art" for oversizing the artwork to correspond with the thickness of the metal. Remember, the etching not only goes down through the metal, it goes sideways into it, so the uppermost part of the metal is eaten away more so than the bottom area, and the resulting tapered slope of the metal depends on what strength of acid you're using. On top of all that, this process really doesn't smell very good.

One of these days, I'll re-learn how to do the artwork, but when I get around to offering P.E. parts for sale, I'll turn the actual etching over to the pros and let them deal with the hassle of chemicals, metal acquisition, prep & disposal.

[Russell C]

Saved this brass parts sheet from two decades back, a double etch one where the first etch was halfway down into the metal on the top sheet surface, then it was flipped over and another pass was done for an etch-through. If I remember right, this sheet was a total reject because the holes were not undersized enough to prevent the acid from ultimately making them too big in diameter. There's an 'art' to the whole process. Run the sheet through the acid too quickly, and you don't get a deep enough etch. Leave the sheet in too long, and too much of the metal disappears.

Edited March 6, 2020 by Russell C
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