I fused the facing on first before cutting. I then figured out on paper before I cut what size each tshirt could be cut to and arranged them from there, so I had rows of different that had the same height, not always the same width, so the side boarders between the blocks varied but the horizontal boarders where the same. I'll attach a picture of one of the quilt I did for my son. for the small designs on the chest or arm, I put 4 together to make one square.

if you have lots of tshirts, I've seen them sewn together in a scrapy type fashion with blocks of fabric scattered around to make the shirts all go together. So no real boarders between the shirts. Lots of ways to do tshirt quilts.

Have you seen the "Too Cool T-Shirts" site? (for some reason whenever I copy/paste the web address in here the link doesn't work, but it's www.toocooltshirtquilts.com.

Their blocks are not the same size, nor is there any sashing. They have a book, but if you don't want to buy it, perhaps you can use the pictures for an idea of how to fit your tee shirt blocks together. Check out "The Process" (button on the left). Pretty neat.

My kids say they don't want a quilt made of their old tee shirts, but I've been saving the shirts in case they change their minds :).

I've made two t-shirts quilts so far with two more to do. Once you get the shirts fused and cut to the largest blocks possible, lay them out and start trimming with the object of arranging same size with same size. Then you get to add borders on those that are the smallest. It really does come together. If I knew how to add a picture at this point, I could show you how my son's soccer coach shirts came together. It took me weeks looking at the shirts to try and figure out how to have blocks with sayings on them and blocks with just a small decal. Once the blocks were laid out on the floor, it was measure, trim and sew borders. The blocks came together.

I just finished making my great-niece a T-shirt quilt for graduation and I did sort of a field fit. I cut out the piece of shirt that I wanted to use with as much extra fabric around it that I could. When I had every thing cut out I did a trial layout. I tried to line up the ones that looked like they would be the same width. Then I worked on making my columns the same length. I did have to piece some of the blocks with some of the leftover material from the shirts they were cut from and trim some up. Then I cut my iron on interfacing to a somewhat common width size and what ever length size. I did not have a pattern so I did do some trimming here and there. I did look at some of the T-shirt quilt sites and got ideas from there. I think it turned out okay but my niece and grandniece were pleased and everyone at the graduation party raved about it.

I recently made a t shirt quilt. I fused the interfacing on in random sizes. Whatever size seemed to fit the design and cut them all out, they all had a little extra t shirt on them. Then I started laying them out. Some wer 10 inches high. SOme only 3 inches. I put them into rows pretty much based on their height. I trimmed as I went and cut each row to the same height. Some I put 2 t shirt logos together to get the right size. I even used the things on some of the sleeves. It came out really nice. I didn't use sashing but I did add a couple of borders. It came out really nice.

I couldn't find my picture of the one I made, but all of my kids want one now. I did use very thin fusible interfacing on the backside of the fabric before I cut out my t-shirts. My son is really into cars and racing. The parts I wanted to save were various sizes. Instead of using sashing, I bought a variety of Nascar, etc. racing type fabrics and put them around each block until I had all blocks the same size. That meant that not all my strips were the same size. Some were pretty large, so I just put fabric on one side or on the bottom. I arranged them in a pleasing manner and put them together. He was in his mid-30s when I gave it to him and it is still his favorite several years later. Sleeps with it every night. Not sure if I should be honored or embarrassed! LOL I guess it's ok with his wife 'cause she likes it too.

Hope this gave you some more ideas.

I cut my interfacing to 12 1/2 " squares then ironed it to the backs of the t-shirts. That size worked for most of the adult size large-xlarge shirts I had. Then when done I put together with square in a square sashing. Here's a pic.

I measure all the designs and add 2 inches for seams and an edge, then take the largest horizontal and largest vertical measurement and cut them all that size. They usually come out about 12x15 and the small designs I use for corner blocks or in the border. Good luck.

I just finished one the same way. It turned out great! It was a Harley t-shirt quilt and the sashing was flames.