Originally Posted by TheMerkleFamily

Welcome! I agree with finding a sewing machine, even if borrowed, vs sewing any of your t-shirt quilt by hand. Yes, interface is a must in order to keep your knit t-shirts from stretching and becoming wonky or distorted. Quilting should be reasonably close to the 4" recommended by the batting manufacturer or you do run the possible risk of the batting not standing up over time. There are great online resources that I spent hours researching before making my 1st t-shirt quilt - lots of articles, videos and even a class on the bluprint website (a great resource for all types of crafting!). Local quilt shops are a great opportunity to get advice and buy your needed items. Mine helped me with interfacing and recommended a few books dedicated to making t-shirt quilts that have a wealth of information.

Another suggestion is to go to the top of this site and search for t-shirt quilts and you'll find previous discussions (threads) on this website with a ton of advice, too! There are so many folks here with experience that are willing to help - keep asking!

And be sure to show us pictures! Good luck