Vintage T-Shirt DIY #Fail

A few weeks ago I was on Pinterest as usual and I came across a pin that led me here:

And I got SUPER excited! I have this old vintage t-shirt form a children's hospital that was Z's thrift store find from years ago, but it is so thin and soft and simply amazing. 

I emailed Z the link and said "we so HAVE to do this!"- he was totally on board.

After reading through the instructions and going to Whole Foods, Raley's, Home Depot, and a local hard ware store I finally found the Sodium Carbonate at the pool supply store. I had to buy a 5lb bag of it but I was so excited I really did care.  *Baking Soda is Sodium Bicarbonate*

I had all of my supplies ready to go! I used a J'Adore Dior shirt which is a little to stiff for my liking but 100% cotton and I thought it would work perfectly.

Per wash load it said to use:
1/4 Cup Sodium Carbonate
2 Cups Salt
(I did a little more of each)

I got to work!

I put the machine on hot water per instructions -

And loaded it with my shirt and a garage towel, waited until the water was done loading and added the ingredients. (Salt & Sodium Carbonate) If you do not wait until the water is done loading the Sodium Carbonate will get into the air and not be pleasant. ;)

I fully washed and dried the items and repeated the instructions - three, four, five, six, and finally seven times. Thats a lot of washing and drying, not to mention salt! 

After every wash cycle I expected to see some sort of change after I pulled it out of the dryer but there was NOTHING! Finally after the last time I noticed a little fading but the shirt was not any softer or thinner. I do have to wonder if a polyester yuck blend shirt would break down faster as most of the vintage shirts in thrift stores are a poly/cotton blend. 

I was very disappointed with the result or lack there of... and definitely do not think I will try this again.

Big time DIY fail.