Etching my own PCB
Vega256
Posts: 197
Hey,
First time fabbing my own PCB. I've been looking around for the method that best fits my needs (there are tons of ways to do this). I've decided to go with the toner transfer method using just glossy paper and an iron.
Has anyone etched any boards using RadioShack's brand of copper-clad two-sided boards? I have seen reports from a small number of people reporting that RadioShack's brand of boards are not good for heating: the fiberglass layer bubbles underneath the copper when heated. Most people, though, have had good results with the brand.
I would like to use Staple's brand of glossy paper, but some complain that their brand of paper, in particular, leaves a substantial amound of glossy film on the copper, preventing the etchant from getting to the copper.
I would just like to hear some opinions from people who've done this before, especially those who've done it with the aforementioned brand names.
First time fabbing my own PCB. I've been looking around for the method that best fits my needs (there are tons of ways to do this). I've decided to go with the toner transfer method using just glossy paper and an iron.
Has anyone etched any boards using RadioShack's brand of copper-clad two-sided boards? I have seen reports from a small number of people reporting that RadioShack's brand of boards are not good for heating: the fiberglass layer bubbles underneath the copper when heated. Most people, though, have had good results with the brand.
I would like to use Staple's brand of glossy paper, but some complain that their brand of paper, in particular, leaves a substantial amound of glossy film on the copper, preventing the etchant from getting to the copper.
I would just like to hear some opinions from people who've done this before, especially those who've done it with the aforementioned brand names.
Comments
Rad shack boards ( last I looked) are brown phenolic not real FR4 or G10 FRP . these phenolic boards are junk to work with really regardless on who makes them .
peter
I have my copies printed at the local UPS store.
one thing about Iron on, it is difficult to use the outside 1/4" of the board,
the traces from the paper don't seem to stick 100% of the time.
so try to keep all the fine traces away from the edges if at all possible...
A very hot iron, and lots of pressure, I don't think you can press to hard,
Just don't let the "owner" of the Iron see this part...:)
You will have to go over your art work with a fine tooth comb to ensure all the traces and pads make it to the copper.
As to the Radio Shack boards, You can solder and drill them as usual, but if you try them in a toaster oven,
You must watch carefully for the solder to reflow, and then turn the heat down ASAP.
in other words, don't leave them in to long.
And don't be to frustrated if your first couple of boards don't work out,
There is a learning curve, so start with a small board if you can.
-Tommy
I've been very happy using an HP inkjet printer on transparency material. Other printer's ink doesn't work for me. While the ink is a little sticky and can be smugged if abused, the images are excellent.
Others have doubled laser printer images of transparencies to get a dense image.
For software, I am still using Eagle CAD. People complain that it is hard to learn. But the libraries for parts are vast and you can always get new downloads.
I use ferric chloride to etch. Other's hate it, but if you are neat about your workspace - it is not bad to use.
I had a terrible time with radioshack stuff ;x
This is the way I ended up going on my second attempt worked much better... http://www.youtube.com/watch?v=tWnfnt2rNO0
The problem I keep running into now is 'package sizes' I am using eagle to lay out the pcb but picking the right package size of resisters and capacitors etc.. etc.. has been a total
nightmare considering none of those specs are on any of the parallax components.. I have been measuring them with a ruler and them picking the package size based off that ;c
Go to Harbor Freight, Home Depot, or Lowe's (maybe even Walmart?) and pick up a cheap digital caliper. Much easier and far more precise. And you can switch between inches and mm with the push of a button. I keep my 'good' set by my desk, and have a cheaper one on the garage workbench.
Thanks, I totally forgot about such devices ;x
Radio Shack boards work good for me.
Radio shack etchant works good for me, although sometimes it takes quite a bit of time.
Usually about 25 minutes in the etchant will finish the board.
I've had success Copying the design on Ink Jet HP photo paper.
I have my design copied on a copy machine at Office Max with the darkest setting I can get that still looks good.
I preheat my board in an old electric frying pan, then iron on the pattern.
I use high heat on the iron and press as hard as I can for about 2 minutes.
I put a weight on top of the ironed on pattern and leave it cool for about 30 minutes.
Then I put it in a water bath until the paper swells and peel it from the board.
If there are small areas that don't transfer quite correctly, I go over them with a Sharpie marker.
There is a company that sells a type of coated paper that releases in water very good.
They used to be called DynaArt Designs years ago.
Jeff
I used to use MG Chemicals pre-sensitized boards as they offer a 6 minute (approximate) exposure time, but I had frequent problems with trace burn-through and scratches. I found GC Chemicals pre-sensitized boards work VERY well. Their exposure time (with a single flourescent bulb at 8") is 30 minutes, but the traces are perfect every time.
I have my transparencies made at Staples on their PHOTO laser printer. The density of black is much better, much more even. I only need a single transparency to expose the board.
I still use MG Chemicals developer, and I use Ferric Chloride to etch. The etch takes a fairly long time, but I don't heat or pump, I just manually agitate by rocking the tray. One of these days I'll get a small pump for this job, it will significantly improve the experience.
If all you are doing for PC Boards is larger, through-hole and not too complex, then the transfer method may be fine, but if you want runs much smaller than .025", in my experience, nothing beats the pre-sensitized, photo-expose methods. This is the only way I have been able to use SOIC chips reliably on my PC Boards, I could never do it with transfer.
Good luck and let us know how it goes!
Dave
PS., If anyone can use it, here's the 300dpi mask blank I use with PhotoShop when I make my layouts by hand. I know it's archaic and one of these days I will get DipTrace or similar customized to do everything I want it to... but this is just for anyone else who hand creates their masks in Photoshop... These patterns have traces for DIP IC's including Stamps, as well as wide and narrow SOICs, 1210 to 0805 resistors/caps, SOT-3, 233, etc., transistors, regulators, and Propeller and EEProm patterns. To use it, be sure to get the FULL size image (click the thumbnail, then CLICK the image that opens to get the high-res (the one that displays is reduced initially).