I use it but I am not in the Greater Boston Area.

Here in KCMO I have to go to older hardware stores. We have one that is local that has just about anything you want. Also Ace Hardware stores here are like this also so that might be an option for you if you have Ace Hardware in your area. Hobby stores that cater to models train, planes and such well often have it also. Another name for it is spring wire. That may help you in your search