MG Chemicals 9" x 6" Positive Presensitized Copper Clad Board, Double Sided, 1 oz Copper, 1/16" Thick, FR4, cat# 660

These are great. I had a little trouble with the traces getting narrow, but overall it was good.The instructions say that they have a white covering - they don't. I finally convinced myself that the material was the presensitization and went with that. I tried sodium carbonate as a developer, but that did not phase it at all. So I used 5 to 1 sodium hydroxide. That worked well, not too fast and not too slow. I didn't have to scrub on most of it, but a couple of places didn't want to come off. So when most of the board was clear, I stopped developing (only a minute or two) and took those areas off by hand. Those areas didn't etch well either.Otherwise the etching with Muriatic acid and hydrogen peroxide was excellent and I came out with good boards.The big minus is the price, but when you mix in several failed boards, this one is hard to beat. The only other method that is close is negative transfer film that you laminate on yourself. The price is better by about half and the only kicker is to get the application of the film onto the board without getting it to stick to everything else. Also when you laminate, it is nearly impossible to get the bubbles out. So you end up 'fixing' the spots with some form of marker. That happens on the positive presensitized also, but not as much. I have found that paint markers work best. I bought the extra fine and found that I could used a dump of paint about 1/4" in diameter on a piece of plastic to dip the tip into for best results.

Great boards for prototyping in a hurry. Sometimes we all get a little behind on our work and this pre sensitized copper clad board just might save you.The final product is really clean and crisp to the thou which is really great. The biggest downfall I have found is it does chip during cutting around the edges which means you have to cut or snap a bit larger than you would anticipate.Overall great product!

I've had much better luck using my own photoresist and copper clad. While this is faster and easier, the results aren't amazing and you can only realistically expect a minimum feature size of about 0.3-0.5mm depending on how careful you are. For small quantity large feature size boards it's pretty economical but any more than that and it gets too expensive pretty quickly.

These boards are great for high resolution prototyping. They work with your existing PCB making process, albeit more expensive. If you are used to making your own photo-resist boards, you will find that these boards require much less exposure time (2-2.5 minutes per side versus 6 minutes) They also develop much faster, you do not want to keep theses boards in the developer for longer than 10 seconds else the artwork will begin to wash away. I keep some of these boards on hand for emergency purposes, but I would not recommend them for production use because of the high cost.

After struggling with clothes irons and Drano, I finally purchased all the 'correct' products; developer, etching solution, and pre - sensitized, double-sided boards. From then on, my boards are perfect, every time. No touch-ups or post scratching required.I use fritzing, photoshop, and a professional exposure table (originally for pad-printing plates), and using mg boards and solutions, I get perfect results every time.for the positives, I use dual-layed, tranparencies, printed on a laser printer.

I keep getting board with bad bits and then it ends up in the BIN. Half of it is good so they only get a half score.