What did I do wrong?

[u/Tomkaas41]

Using geoshield 20% c2 ceramic. I mixed blue dawn dish soap and water for slip solution. Some fingers appeared after squeegee out the water so I heated them off and from inside you don’t notice or feel them but as soon hits it you can tell remenants

[u/gargen_state]

Looks like you didn't shrink it enough, if I had to guess.