Comments on: PCB Iron-On Etch Resist Problems (and Solutions)

By: Keith Neufeld

Keith Neufeld — Sun, 21 Sep 2014 21:06:23 +0000

Ivor, the printed material in the magazine is ink that’s dried on the page. The toner transfers because it’s plastic melted to the page and re-melts when you iron it. I haven’t used magazine paper myself but I hear it works!

By: Ivor Cadiramen

Ivor Cadiramen — Thu, 19 Dec 2013 04:41:16 +0000

Re the use of Magazine Paper, please excuse my ignorance but wouldn’t the printed material in the magazine page transfer as well. I have had reasonable (not great) success with cheap dollar shop photo paper. I too use the HCl:H2O2 combination – less hassle from the homefront than the FeCl3.

By: komradebob

komradebob — Fri, 06 Apr 2012 22:12:44 +0000

Thanks for the writeup.

I use the muriatic acid / peroxide etchant. Works like a charm, especially if you keep it warm.

The ultimate thing to use instead of an iron…Steal the fuser assembly out of a dead laser printer. My HP 5Si croaked a few years ago and I didn’t have the heart to pitch it. It now lives on serving as the press-n-peel to pcb fuser. I hook it up to the mains , keep an eye on the temp sensor with an ohmmeter, turning the lamp off when it gets warm enough and crank the boards through by hand 5 or 6 times. Then quench them under cold water. Works like a charm!

Mark K – I love your idea of hot water bath and plastic bag. Really makes life easy. I use disposable plastic food containers that Chinese food comes in.

By: Keith Neufeld

Keith Neufeld — Thu, 03 Mar 2011 12:48:52 +0000

Graham, I’m not using a laminator; I’m using a clothes iron.

By: Graham Rounce

Graham Rounce — Thu, 24 Feb 2011 22:23:26 +0000

Hi – I’m looking at laminators, and the “maximum document thickness” they accept seems to be about 0.6mm. Can you still get a 1.5mm(?) pcb through easily, or are you using a special “thick document” laminator?!

Thanks,

By: Mark K

Mark K — Thu, 03 Jun 2010 14:22:35 +0000

I liked your lessons as well. I tried a lot of things to etch and finally have a kit in a plastic shoe box. Not much is original, but it has been tweaked for performance. If you are a member of the Automobile Club you receive the Westways magazine. It is about the best ‘free’ source of transfer paper I have found. I use a GBC laminator and a green scrub pad on the boards. My etchant is FeCl and my ‘tank’ is a Zip-Lock freezer bag. This is immersed in hot water held in my plastic shoebox. Agitation is a trim paint roller applied to the outside of the plastic bag. Etching is very fast and controllable, the water bath both heats and helps dilute any leaks. The primary advantage is that this technique uses very little etchant and as long as your board has not poked any holes in the bag, very clean. I clean the toner off using a worn green scrub with laquer thinner, much better than acetone. Disposable rubber gloves keep the etchant at bay.
The effectiveness of the bag, hot water, and roller cant be overstated, it takes about fifteen minutes to do a 3×5 board with about two ounces of etch. No great board prep either, a scrub until matte with plain water and a dry with a paper towel. Wrap board in printed page and secure with scotch tape. Run through the laminator a few times, cool and soak in warm/cold water for a few minutes. This sort of paper does not leave much of itself on the transfer. I have tried the Staples cheap photo paper and it just does not work as well as the magazine paper.

By: Keith Neufeld

Keith Neufeld — Fri, 12 Mar 2010 20:26:51 +0000

Keith T, as an electrician or plumber, you’d be too “close” to PVC pipe and just see it as conduit. To an outsider, it’s a cool cylinder good for holding things.

By: Keith T

Keith T — Fri, 12 Mar 2010 16:17:04 +0000

thanks for a great idea! i never thought to use PVC pipe for this application. And i was an electrician for years.
thanks again!
Keith T

By: Rob Reeder

Rob Reeder — Mon, 29 Oct 2007 20:32:13 +0000

Sounds like you’re getting lots of experience. Back in the days of Iron-on etch resist (only a couple years ago), we built an aluminum box and tied it to a vacuum cleaner. We added a baffle to the side with perforations at the top.

We laid the PCB, copper side up, Iron-On etch-resist on top of that, then a layer of plastic oven bag material on top. Suck it all down with the vacuum cleaner, adjust the baffle so we don’t burn up the shop vac, and hit the pcb with a heat gun. Cook until the white paper turns the color of a ready-to eat, golden brown marshmallow.

Shut off the vac and allow to cool SLOWLY over about 30 minutes. Make an inspection to ensure the toner is still stuck to the corners. If it’s good, soak it in still water until the paper floats away.

SLOWLY drain the water, and hit it with the heat gun again to final set the etch resist. Non-adhering etch resist will shrivel up.

Touch up with a black Sharpie under an inspection microscope.

Big Secret: Before doing the transfer, thoroughly clean with soap/water, and rinse to get all the soap off, and air dry. At the very last moment, go over the copper with fine grit sand paper to give the etch resist something to grab on to.

Never use alcohol before transferring since it leaves a fine white dust that acts like a mold release. It’s the same reason we need to get all the soap off.

As far as etching goes, my best work was in 1/2 full tupperware while shaking like crazy. Skip the trip to the Gym on the day you do that. 1 oz. Copper came off in about 2 minutes. As the etchant gets old, it’ll take longer.

Nowadays, we have this automated dremel thing that grinds the copper off.

By: Keith Neufeld

Keith Neufeld — Thu, 23 Aug 2007 11:36:07 +0000

Tom –

Right now I’m drilling most of my boards on my friend’s CNC drill machine. I get best alignment drilling the holes (perfectly positioned) first, then aligning the iron-on transfer to the holes by holding it up to the light. Transfer-then-holes requires careful alignment on the drill machine that’s not easy with the software he uses.

When I hand-drill holes, I definitely etch first.

But . . . as you can see, I got past the dimpling/ahesion problem just by putting a pad under the iron. Which seems to help give me more consistent results anyway. Of course, your mileage may vary.