Abstract: A method of making strengthened articles that includes: providing articles comprising ion-exchangeable alkali metal ions and first and second primary surfaces; providing a bath comprising ion-exchanging alkali metal ions larger in size than the ion-exchangeable ions; and submersing the articles in the bath at a first ion-exchange temperature and duration to form strengthened articles. Each strengthened article comprises a compressive stress region. Further, the exchange rate of the ion-exchanging alkali metal ions is higher into the first primary surface than into the second primary surface. In addition, the submersing step is conducted such that a predetermined gap is maintained between the first primary surface of each of the articles.