ABCFab on eBay. I've bought 1oz copper clad from him for years. He usually has some black FR-4, too. He also has 2oz if you ever need any. But, 2oz actually takes about 4 times as long to etch than 1oz.Looks like he is on vacation now. It usually clos3s in August for a few weeks.https://www.ebay.com/str/pcblaminatescopperclad
I'm guessing the big smiling "A" isn't it. I welcome your opinions.TIA