I have made 5 and always use stabilizer just to be safe.

Yes, use a stabilizer -- two of my bee members have made many tshirt quilts and always use a stabilizer with no problems at all!!

I have made numerous T-shirt quilts. I only use stabilizer if the T-shirt is very thin. Otherwise 90% of the blocks are without stabilizer. I do NOT send mine out to be quilted. Instead I quilt them on my domestic machine. I stabilize the quilt by stitching in the ditch of each block first. Then I go back and stitch in each block. here is a link to one of my T-shirt quilts. look for the entry by lakekids

http://www.quiltingboard.com/main-f1...ml#post4790296

I use light weight tricot on the back of the T-shirts. Remember the T's stretch around your body, so the tricot should stretch the other way, up and down. That way the fabric is stabilized and good for quilting on.