Author Topic: DIY etching PCB's - Toner Method or Photo Resist Method?  (Read 6199 times)

joel_ostrom

Just getting into some tinkering with Pedal clones, want to start etching my own PCB's. I've seen some vids on youtube and read lots of tutorials. Just wondering which is the preferred method among you guys.

Toner Method - transfer toner from printed diagram to a copper board via heat, using the toner drawn on the copper to draw the traces

UV Exposure - Using photo sensitive boards with a diagram printed on transparent paper. Using the unexposed trace sections as the traces.

which is the better method for a beginner circuit board builder?
Which do you prefer?
Why?

Cheers!

R O Tiree

Re: DIY etching PCB's - Toner Method or Photo Resist Method?
« Reply #1 on: May 27, 2013, 06:01:48 AM »
Toner Method

Requires a lot of patience every time. Sure, you get good at it over time, but it still takes a while to get the board up to temperature, ensure that every scrap of toner gets transferred. Then, if using the glossy paper method, there's all the faffing about rubbing the paper fibres off in soapy water... That said, people can get down to 0.015" traces and lower once they acquire the skill sets.

Photo-Resist Method

Takes a little while to ascertain the required exposure time with a few experiments (make sure you always warm your UV tubes up).  After that, the process is pretty much fool-proof. Requires another chemical to develop the board - your supplier will be able to recommend the right one, as some boards are designed for specific solutions. The most usual, however, is a weak Sodium Hydroxide solution. As I said, ask your supplier. Accuracy can be very good indeed, given good quality board. I regularly get down to 0.005" traces, although I usually stick to 0.012" as a minimum. I used to spray my own photo-resist, but that is fraught with problems - consistent thickness, cat hair, dust, moisture, etc. If you can't govern the thickness, you can't judge the exposure time correctly, for example.  Now I just buy the pre-sensitised boards. It's more expensive than toner transfer, but the reuslts are much quicker and more accurate, IMO.

Start with something small using quite thick traces, so you don't waste boards as you learn the ropes of either method.

Overall

Toner transfer is very cheap, requires no extra chemicals (aside from soapy water!) but it's always time-consuming and takes a while to master.

Photo-resist requires extra chemicals and a UV box (prices vary but good ones can be expensive) but, after the initial calibration process, it's very quick to do and stunningly accurate for the home builder.

I tried Press'n'Peel - didn't get on with it at all. Tried glossy paper transfer. Messy and time-consuming. Tried spraying my own boards with photo-resist. Got quite good at it, but QA is very hard in a draughty house with 6 cats and 4 dogs. Now I just buy pre-sensitised boards and suck up the costs in exchange for the reduced time spent on them.

My advice is to try the cheap methods first, then invest in the extra equipment and move onwards and upwards when you get good at design and need the extra time.
...you fritter and waste the hours in an off-hand way...

stevie1556

Re: Re: DIY etching PCB's - Toner Method or Photo Resist Method?
« Reply #2 on: May 27, 2013, 12:32:45 PM »
I've used both, but I much prefer the UV method. Much easier and quicker to do. But I do have a proper UV exposure box. After seeing videos on YouTube you can use a bulb and do it like that, which is essentially what a UV box does, but without the box.

When I etch my boards, I have a heated bubble etch tank, but they are reasonably expensive, but I always had good results from soaking a sponge in ferric chloride and rubbing it over the board for a while.

davent

Re: DIY etching PCB's - Toner Method or Photo Resist Method?
« Reply #3 on: May 27, 2013, 04:31:00 PM »
Guys i've never had a brand of board that didn't produce great results just using regular everyday fluorescent tubes for exposures, the uv light will afford a shorter exposure time but there's no need for one.  I can easily go from printing out a transparency to having the etched, ready to drill board in under a half hour, the uv light will trim a few minutes off that total.

dave
"If you always do what you always did- you always get what you always got." - Unknown
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therecordingart

Re: DIY etching PCB's - Toner Method or Photo Resist Method?
« Reply #4 on: May 28, 2013, 02:31:22 PM »
I use both methods, but prefer toner transfer. Both took an extensive amount of time to get right, and both took a bit of an investment money wise. If you are doing one-off boards then do toner transfer. If you are doing large batches or multiple runs of the same board I'd do the photo method. The extra chemicals and transparencies add to the cost of the photo method.

The tricks to getting consistent toner transfers are clean boards and NOT using an iron for applying heat. Spend the $60 on a laminating machine at your local office supply store, and run the board through the machine a few times. Peel off our paper and etch away.


smallbearelec

Re: DIY etching PCB's - Toner Method or Photo Resist Method?
« Reply #5 on: May 28, 2013, 02:56:37 PM »
I offer tutorials and kits for both P'N'P and the positive photo process, and I have used both extensively.

https://www.smallbearelec.com/HowTos/DirectPCBoards/DirectPCBoards.htm
https://www.smallbearelec.com/HowTos/PhotoPCBoards/PhotoPCBoards.htm
http://www.smallbearelec.com/servlet/Categories?category=PC+Boards%2FPrototyping%3APC+Board-Making+Kits

Either will work consistently well. My personal preference is the photo process, because it does not require a laser printer. I agree that a UV box is not necessary for exposure. If you always use the same fluorescent light source, a few experiments will get you the right exposure time. I strongly recommend using Window Decal stock for your making your masks. The less-than-full transparency of translucent stocks doesn't give enough contrast and makes exposure time too critical. Re the developing solution, it's easy to make from household Lye, but please follow every precaution on the can!

Regards
SD

deadastronaut

Re: DIY etching PCB's - Toner Method or Photo Resist Method?
« Reply #6 on: May 28, 2013, 03:25:28 PM »
i'm quite happy with the results i get using toner transfer/iron on....never had a problem with it...let cool, peel.

i use my spent box etchant warmed up.....waste not, want not. :)

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