You only have to pay estimated taxes if your full time job withholding is not adequate.
Are you claiming 1 or 2 on your W4 at work? If so, lower that to 0 or choose 0 plus additional $10/$25 per paycheck. You don't need to make estimated tax payments if you can pay in more via your FT job.
Etsy is tough- do you expect this to have a major positive result on your income? If so, then you may need to make estimated tax payments if you aren't used to a sizable refund from the W2 job.
You don't make estimated taxes for the W2 job- they already take out taxes.
Your tax liability just from the Etsy work might be 15% for Self-Employment Tax plus 15-20% for regular income tax (depending on high your income is in general) on the net income (income minus all expenses).
You are not required to pay estimated taxes if your W2 withholding can cover this.
