Table of Contents

1

Exhibit 31(b)

SECTION 302 CERTIFICATION

I, John P. Zimmer, certify that:

1.

I have reviewed this annual report on Form 10-K of Core Molding Technologies, Inc.;

2.

Based on my knowledge, this annual report does not contain any untrue statement of a material fact or omit to state a material

fact necessary to make the statements made, in light of the circumstances under which such statements were made, not

misleading with respect to the period covered by this annual report;

3.

Based on my knowledge, the financial statements, and other financial information included in this annual report, fairly

present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for,

the periods presented in this annual report;

4.

The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and

procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as

defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and we have:

a)

designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be

designed under our supervision, to ensure that material information relating to the registrant, including its

consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in

which this annual report is being prepared;

b)

designed such internal control over financial reporting, or caused such internal control over financial reporting to

be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting

and the preparation of financial statements for external purposes in accordance with generally accepted

accounting principles;

c)

evaluated the effectiveness of the registrant ’s disclosure controls and procedures and presented in this report our

conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered

by this report based on such evaluation; and

d)

disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during

the registrant’s most recent fiscal quarter (the registrant ’s fourth fiscal quarter in the case of the annual report)

that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over

financial reporting.

5.

The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over

financial reporting, to the registrant’s auditors and the audit committee of registrant ’s board of directors (or persons

performing the equivalent functions):

a)

all significant deficiencies and material weaknesses in the design or operation of internal control over financial

reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and

report financial information; and

b)

any fraud, whether or not material, that involves management or other employees who have a significant role in

the registrant’s internal control over financial reporting.

Date: March

11, 2021

/s/ John P. Zimmer

John P. Zimmer

Vice President, Secretary, Treasurer and Chief Financial Officer