<PAGE>   1
                                                                 Exhibit 10.14c

                            STOCK PURCHASE AGREEMENT
                            ------------------------


           This Agreement, dated as of September 30, 1997, is by and between
UNIFRAX CORPORATION, a Delaware corporation, ("Seller") and BP EXPLORATION
(ALASKA) INC., a Delaware corporation, ("Purchaser").

           WHEREAS, Seller is a Delaware corporation authorized to issue
preferred stock as set forth in the Certificate of Incorporation of Seller,
amended by a Certificate of Amendment dated April 21, 1997; and

           WHEREAS, Purchaser is currently the holder of 2,000 shares of the
common stock of Seller; and

           WHEREAS, Purchaser desires to purchase from Seller, and Seller
desires to sell to Purchaser, 166.67 shares of the preferred stock of Seller,
subject to the terms and conditions of this Agreement.

           NOW, THEREFORE, in consideration of the premises and covenants
contained in this Agreement, and for other good and valuable consideration, the
receipt and adequacy of which are hereby acknowledged, Seller and Purchaser
agree as follows:

                                    ARTICLE

                          PURCHASE AND SALE OF SHARES
                          ---------------------------

           0.1   Transfer of Shares. Subject to the terms and conditions
contained in this Agreement, Seller shall sell, transfer, assign, convey and
deliver to Purchaser, and Purchaser shall purchase from Seller, One Hundred
Sixty-Six and 67/100 (166.67) shares of the preferred stock of Seller (the
"Shares").

           0.2   Purchase Price. Purchaser shall pay to Seller for the sale,
transfer, assignment, conveyance and delivery of the Shares an amount equal to
$250,000 (the "Purchase Price"). As payment of the Purchase Price, Purchaser
shall, at its option, (a) pay to Seller $250,000 in cash or (b) issue to Seller
a credit in the amount of $250,000 against interest payable pursuant to the
Subordinated Promissory Note of Seller, dated October 30, 1996, in the original
principal amount of $7,000,000 (the "Note").

           0.3   Pre-Emptive Rights. Purchaser acknowledges that the right to
purchase the Shares pursuant to this Agreement satisfies any right it may have
to purchase any shares of the preferred stock of the Seller in connection with
Seller's sale of 1,500 shares of such preferred stock to Unifrax Holding Co.,
whether pursuant to the Stockholders Agreement, dated as of October 30, 1996,
among Seller, Purchaser and Unifrax Holding Co. (the "Stockholders Agreement"),
applicable law or otherwise.



<PAGE>   2


                                       2


                                   ARTICLE 1
                                    CLOSING
                                    -------

           2.1   Effective Date. The transfer referred to in Section 1.1 of this
Agreement shall be effective (the "Closing Date") as of the earlier of (a)
Purchaser's tendering to Seller $250,000 in cash or (b) October 30, 1997 (or,
if any reason the first interest payment to be made by Seller to Purchaser
under the Note is not made on or prior to October 30, 1997, November 9, 1997).

           2.2   Certificate. Seller shall issue to Purchaser on the Closing 
Date a certificate evidencing Purchaser's ownership of the Shares. Such
certificate shall be in form and substance, and shall be executed and delivered
in a manner, reasonably satisfactory to Purchaser.

           2.3   Payment. Purchaser shall pay the Purchase Price on the Closing
Date. If Purchaser decides to pay the Purchase Price by issuing to Seller a
credit in the amount of $250,000 against interest payable pursuant to the Note,
Purchaser shall execute and deliver to Seller a receipt or other documentation
requested by Seller in connection with such credit.

           2.4   Termination. If for any reason the Purchase Price is not
received by Seller on or before the Closing Date, Seller shall so notify
Purchaser and Purchaser shall have two business days after such notification to
pay the Purchase Price. If the Purchase Price is not received by Seller prior
to the expiration of those two business days, this Agreement shall
automatically terminate and Purchaser shall not have any right to purchase the
Shares, whether pursuant to this Agreement, the Stockholders Agreement,
applicable law or otherwise. Notwithstanding the termination of this Agreement
pursuant to this Section, Seller reserves all rights and remedies it may have
against Purchaser in connection with the failure to pay the Purchase Price
pursuant to this Agreement.

           2.5   Time is of the Essence. Time is of the essence under this
Agreement.

                                   ARTICLE 2
                    REPRESENTATIONS AND WARRANTIES OF SELLER
                    ----------------------------------------

           Seller hereby represents and warrants to Purchaser as follows:

           2.1   Title. Seller is transferring to Purchaser on the Closing Date
good and marketable title to the Shares pursuant to this Agreement, free and
clear of any lien, security interest or encumbrance of any kind.

           2.2   Authorization. Seller has all necessary power and authority, 
and has taken all action necessary, to (a) execute and deliver this Agreement,
(b) consummate on the Closing


<PAGE>   3


                                       3

Date the transaction contemplated by this Agreement and (c) perform its
obligations pursuant to this Agreement.

           2.3   Enforceability. This Agreement has been duly executed and
delivered by Seller and is a legal, valid and binding obligation of Seller,
enforceable against Seller in accordance with its terms, except that the
validity, binding effect or enforceability of this Agreement may be limited or
otherwise affected by (a) any bankruptcy, insolvency or other similar law
affecting the enforcement of creditors' rights and remedies generally or (b)
principles of equity.

                                   ARTICLE 3
                  REPRESENTATIONS AND WARRANTIES OF PURCHASER
                  -------------------------------------------

           Purchaser hereby represents and warrants to Seller as follows:

           3.1   Authorization. Purchaser has all necessary power and authority,
and has taken all action necessary, to (a) execute and deliver this Agreement,
(b) consummate on the Closing Date the transaction contemplated by this
Agreement and (c) perform its obligations pursuant to this Agreement.

           3.2   Enforceability. This Agreement has been duly executed and
delivered by Purchaser and is a legal, valid and binding obligation of
Purchaser, enforceable against Purchaser in accordance with its terms, except
that the validity, binding effect or enforceability of this Agreement may be
limited or otherwise affected by (a) any bankruptcy, insolvency or other
similar law affecting the enforcement of creditors' rights and remedies
generally or (b) principles of equity.

                                   ARTICLE 5
                                INDEMNIFICATIONS
                                ----------------

           5.1   Seller. Seller shall indemnify and hold harmless Purchaser from
and against each claim, damage, expense, liability or loss incurred by
Purchaser (including, but not limited to, any fees and expenses of counsel to
Purchaser) to the extent such claim, damage, expense, liability or loss results
from any warranty or representation made by Seller being untrue or misleading
in any respect.

           5.2   Purchaser. Purchaser shall indemnify and hold harmless Seller
from and against each claim, damage, expense, liability or loss incurred by
Seller (including, but not limited to, any fees and expenses of counsel to
Seller) to the extent such claim, damage, expense, liability or loss results
from any warranty or representation made by Purchaser being untrue or
misleading in any respect.



<PAGE>   4


                                       4

                                   ARTICLE 6
                                 MISCELLANEOUS
                                 -------------


           6.1   Applicable Law. This Agreement shall be construed, interpreted
and the rights of the parties determined in accordance with the laws of the
State of Delaware, without regard to principles of conflicts of law.

           6.2   Headings. The headings of the articles and sections of this
Agreement are inserted for convenience of reference only and shall not affect
the meaning or interpretation of this Agreement.

           6.3   Waiver. No failure of Seller or Purchaser to require, and no
delay by Seller or Purchaser in requiring, the other to comply with any
provision of this Agreement shall constitute a waiver of the right to require
such compliance. No failure of Seller or Purchaser to exercise, and no delay by
Seller or Purchaser in exercising, any right or remedy under this Agreement
shall constitute a waiver of such right or remedy. No waiver by Seller or
Purchaser of any right or remedy under this Agreement shall be effective unless
made in writing. Any waiver by Seller or Purchaser of any right or remedy under
this Agreement shall be limited to the specific instance and shall not
constitute a waiver of such right or remedy in the future.

           6.4   Binding. This Agreement shall be binding upon Seller and
Purchaser and upon each successor and assignee of Seller and Purchaser and
shall inure to the benefit of, and be enforceable by, Seller and Purchaser and
each successor and assignee of Seller and Purchaser; provided, however, that
neither Seller nor Purchaser shall assign any right or obligation arising
pursuant to this Agreement without first obtaining the written consent of the
other party.

           6.5   Entire Agreement. This Agreement contains the entire agreement
between Seller and Purchaser with respect to the subject of this Agreement, and
supersedes each course of conduct previously pursued, accepted or acquiesced
in, and each oral agreement and representation previously made, by Seller or
Purchaser with respect thereto, whether or not relied or acted upon.

           6.6   Modification. No course of performance or other conduct
hereafter pursued, accepted or acquiesced in, and no oral agreement or
representation made in the future, by Seller or Purchaser, whether or not
relied or acted upon, and no usage of trade, whether or not relied or acted
upon, shall modify or terminate this Agreement, impair or otherwise affect any
obligation of Seller or Purchaser pursuant to this Agreement or otherwise or
operate as a waiver of any such right or remedy. No modification of this
Agreement or waiver of any such right or remedy shall be effective unless made
in a writing duly executed by Seller and Purchaser.



<PAGE>   5


                                       5

           6.7   Severability. Whenever possible, each provision of this
Agreement shall be interpreted in such a manner as to be effective and valid
under applicable law. However, if any provision of this Agreement shall be
prohibited by or invalid under such law, it shall be deemed modified to conform
to the minimum requirements of such law, or, if for any reason it is not deemed
so modified, it shall be prohibited or invalid only to the extent of such
prohibition or invalidity without the remainder thereof or any other such
provision being prohibited or invalid.


           IN WITNESS WHEREOF, Seller and Purchaser have executed this
Agreement on the day and year indicated at the beginning of this Agreement.

                              UNIFRAX CORPORATION



                              BY /S/WILLIAM P. KELLY
                                 -----------------------------
                                 NAME: WILLIAM P. KELLY
                                 TITLE:   PRESIDENT

                              BP EXPLORATION (ALASKA) INC.



                              BY /S/P. D. WILBUR
                                 -----------------------------
                                 NAME: PETER D. WILBUR
                                 TITLE:   SECRETARY