DIY photo etch?

[scottgirvan]

Hi,
Would anyone have a link(s) to a DIY photo etch system. I've seen the one at Micro Mark. Being in Canada I would need the export version and then find the chemicals here. Just wondering if there are any other solutions out there. Can't seem to Google much.
Thanks.

[tetsujin]

Hi,
Would anyone have a link(s) to a DIY photo etch system. I've seen the one at Micro Mark. Being in Canada I would need the export version and then find the chemicals here. Just wondering if there are any other solutions out there. Can't seem to Google much.
Thanks.

I haven't tried it yet but there's a system I read about that interests me: Galvanic etching with copper sulfate. (See also pages on Green Art...)

The most common etching process is a simple corrosive, usually ferric chloride. This has a number of implications. First, the solution's potency decreases as you use it. Second, usually (and in particular, with ferric chloride) the solution is dangerous by touch and odor, and is very effective at staining anything it touches.

Galvanic etching requires a fairly robust power supply - but it has several advantages. First, the effectiveness of the solution remains pretty much constant. (The galvanic process removes copper from your plate, and deposits copper on the opposing electrical terminal.) Second, for a given mixture of solution, temperature, and power supply setting, the time required to establish a certain level of etching is pretty consistent, which means it's easier to get consistent result.

So that might be an option to consider. The equipment and chemicals are a bit different than regular etching - the main thing in common between both methods is you need a method to get the pattern onto the plate in the first place. The Micro-Mark set uses a photo-transfer resist system - another option that may be simpler to get (if the export set doesn't include everything for the resist) would be a toner transfer method with a laser printer. (There are special papers you can use for toner transfer - though I have seen some places that recommend using plain old photo paper...) I think these methods aren't as good or reliable as photo resist, but it could be a handy way to get started.

If you go with good old ferric chloride - it's pretty common as it's used for etching circuit boards as well (those not produced by a milling machine, I mean) - around here they even have it in Radio Shack. I believe you can also get FeCl in dry form as well, and then mix it with water to make your own solution.

[Dr. Yo]

MacFrank has a very good article on DIY photo-etching on the main site.

http://www.starshipmodeler.com/tech/fh_pe.htm

[macfrank]

I have an article here at SSM on making PE. The chemicals are cheap, but corrosive and for best results, you still need a laminator.

I haven't done much with the galvanic methods, but it is an interesting way to etch. The main drawback there is that for best results you need a good regulated, current limited power supply that can provide a fair amount of power into what is effectively a short circuit. They'll run between $80 and $300+.

Ferric Chloride is cheap, but it's a real PITA to use, since it's opaque and stains badly. Drop some on the floor or your clothes and it's never coming out.

[scottgirvan]

Thanks a million everyone. I will look into this.

[ajmadison]

I won't repeat what's been extensively researched, but my take on DIY photo-etch, is the most critical aspect is getting good resolution of the imprint of the acid-resist on the blank. The pasta-machine laminator is only poor resolution. The slightly better motorized laminator is better. But for sub 1mm resolution with consistent results, you need one of those expensive professional laminators, or switch over to a professional photo-resist set ups.

While I'm at it, I've researched Laser Engravers, also know as a laser CNC (
Computer Numerical Control) mill/machine tool. While some have enough wattage to engrave metal, the lower wattage models have enough power to cut sheet styrene, with sub millimeter accuracy. The short version of this story is, unless you find a used one for sale (and sometimes they do show up on E-bay), that's USB compatible, and accepts a non-proprietary CAD file format, you'll spend close to $2000 to put one on your desk at home.

[macfrank]

The slightly better motorized laminator is better. But for sub 1mm resolution with consistent results, you need one of those expensive professional laminators, or switch over to a professional photo-resist set ups.

This circuit board was made with the laminator in my article and a Press N' Peel toner transfer sheet. The traces are just under 0.25mm wide and this was the worst of 8 boards - it etched through the ground plane on one edge of the board where a chunk of the Press N' Peel material was scratched.

I've made 1/1400 and 1/2500 PE figures (less than 1mm long and less than 0.25 mm wide) with the Press N' Peel and an iron - which produces less than great results. Sub millimeter resolution is not the problem.
The main issues with the toner transfer method are getting large areas of toner to stick to the brass, and producing relief etching. For good relief etching and sub 0.1mm details, you need to use a photographic process.

You can get some relief detailing with a laminator and toner transfer by making a double sided PE sheet, but that takes some work.

[Joseph Osborn]

Scott,
For my workshop photoetching needs, I've found that photosensitive dry resist is the most reliable production method. I use an ordinary 500W halogen worklight to expose the resist and common hardware store chemicals to develop and etch. I etch on both sides of the brass and while my results aren't quite as good as the big guys like Eduard, they are really, really good for a homebrew operation.

[scottgirvan]

Thanks all.
Joseph, care (or have the time) to go into detail about your methods?

[ajmadison]

I've made 1/1400 and 1/2500 PE figures (less than 1mm long and less than 0.25 mm wide) with the Press N' Peel and an iron - which produces less than great results. Sub millimeter resolution is not the problem.
The main issues with the toner transfer method are getting large areas of toner to stick to the brass, and producing relief etching. For good relief etching and sub 0.1mm details, you need to use a photographic process.

Sorry, hope I didn't step on anyone's toes. I should have thought about how old some of my research on DIY etching is. Of course the technologies should have improved since then.

[Joseph Osborn]

Thanks all.
Joseph, care (or have the time) to go into detail about your methods?

Actually, time is a little tight for me these days. I'll work up a summary of my methods and shoot them to you.

Joseph

[macfrank]

Sorry, hope I didn't step on anyone's toes. I should have thought about how old some of my research on DIY etching is. Of course the technologies should have improved since then.

Not a problem. The toner transfer method works best when you can control the temperature and pressure. That's why you need a laminator. Some people can get very good at it using a regular iron, but I never got consistent results with one.
Photographic methods are fine, but they seem cumbersome for the occasional PE job. Of course, if you don't have access to a laser printer it's one of the few options available.