QuickLinks -- Click here to rapidly navigate through this document

EXHIBIT 99(b)

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

        In connection with the Annual Report of MagStar Technologies, Inc. (the "Company") on Form 10-KSB for the fiscal year ending December 31, 2002 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Joseph A. Petrich, Treasurer and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant § 906 of the Sarbanes-Oxley Act of 2002, that:

        (1)  The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

        (2)  The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/  JOSEPH A. PETRICH Joseph A. Petrich
Treasurer and Chief Financial Officer
March 27, 2003

        This certification is provided pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and shall not, except to the extent required by such Act, be deemed to be filed by the Company for purposes of Section 18 of the Securities Exchange Act of 1934, as amended.

QuickLinks

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002