I personally have not heard of this brand, but I did Google the Dutch Boy 1/8" solder. There were many pictures of Dutch Boy solders that came up. Most of the pictures had some description of the alloys in it, 60/40, 50/50, acid core, rosin core, etc. I also saw where many came up that are listed for sale on eBay. If you can find any item number or identifying numbers on it, you can call or email Dutch Boy and see if they might be able to help you identify it or you can try Googling the name with the numbers and see what comes up. Check and see if the seller is a stained glass person too. If you buy it and are not happy with it, can you return it to get your money back? I say this because I bought a 5lb roll of 60/40 solder that was advertised for stained glass, and when I got it, it was a rosin core solder for electrical applications and I ended up having eBay force the person to take it back as it was listed incorrectly and they tried to use the phrase of "buyer beware" and refused to return my money. So basically, it comes down to you trying to figure out what the solder's application is, or will you be happy with paying for something you are not sure you will be able to use for stained glass and take a chance. Another word on old solder I bought some old 50/50 solder real cheap, like 40+ pounds, for stained glass application, but it was not properly stored, and before I can use it, I must use steel wool on it to take off all the dirt and whatever else it has on it, which I do not mind doing as I got it at such a good price ($20.00), but I also knew it was for stained glass. I noticed that some of that old Dutch Boy solder is dirty and crusty that is listed for sale on eBay. Good luck!