Experimental studies of a heat exchanger with an improved plate's heat transfer surface are carried out. In the article, various types of solders were investigated and on the basis of the obtained results the technological process of soldering was developed. Testing for the leakage and destruction limit of the heat exchanger was done. The results showed that in comparison with the traditional copper solder in aggressive environments the developed solder composition is close to the chemical composition of stainless steel grades 304/316 and has the same stainless properties as the base material, which provides higher resistance. Tests for the leakage and final strength showed that the additional reinforcing elements added in the design of the heat exchanger improve the reliability of the solder joint, as well as the overall strength of the structure in comparison with the analogue.