A glazing panel system is provided using retention clips formed of folded sheet metal having a top flanges for engaging and retaining a pair of glazing panel ends against uplift forces generated by high velocity winds flowing across the glazing panels. The preferred one piece retention clip has a two ply central web which is formed on the retention clip to be positioned at a seam between adjacent glazing panels and these plies may be welded together to increase the strength of the central web. This top flange is strengthened to resist bending of its right or left flange section by raised portions extending normal to the fold lines that join the respective top flange sections to the top of the central web. A base flange, preferably with left and right flange sections, is bent from the sheet metal blank. The illustrated base flange may have a flange section with raised portions stamped in the sheet metal blank to a height equal to fastener heads used to secure the other flange section to an underlying support. The preferred method of making the retention clip is to fold a blank of sheet metal to bend the blank at the fold lines to form a two ply top flange, a two ply central web and a base flange. The preferred retention clip also is formed with spot welds to join the two plies of the central web and with struck or raised portions such as ribs in the top flange to strengthen the clip against deformation. In another embodiment, a pair of separate retention clip halves are each formed with upstanding central webs to be positioned in the seam of a pair of adjacent ends of glazing panels. Preferably, a progressive die of a stamping press is used to stamp apertures in the metal blank, to form upstruck ribs in the top flange and to bend the flat sheet blank into the shape of the retention clip. The preferred retention clip is made of stainless steel which is stronger than the usual metal used for retention clips and which is resistant to galvanic corrosion when attached to an aluminum support.