[LETTERHEAD OF GIBSON, DUNN & CRUTCHER LLP]

                                                                   EXHIBIT 5.01
                             August 27, 1997




(212) 351-4000                                                   C 30620-00004
Falcon Building Products, Inc.
Hart & Cooley, Inc.
Mansfield Plumbing Products, Inc.
DeVilbiss Air Power Company
SWC Industries, Inc.
Ex-Cell Manufacturing Company, Inc.
Two North Riverside Plaza
Chicago, Illinois  60606

     Re:  EXCHANGE OF 9 1/2% SENIOR SUBORDINATED NOTES DUE 2007 
          AND 10 1/2% SENIOR SUBORDINATED DISCOUNT NOTES DUE 2007

Ladies and Gentlemen:

     We have acted as counsel for Falcon Building Products, Inc., a Delaware 
corporation (the "Company"), and its wholly-owned subsidiaries Hart & Cooley, 
Inc., a Delaware corporation, Mansfield Plumbing Products, Inc., a Delaware 
corporation, DeVilbiss Air Power Company, a Delaware corporation, SWC 
Industries, Inc., a Delaware corporation, and Ex-Cell Manufacturing Company, 
Inc., an Arkansas corporation (collectively, the "Guarantors"), in connection 
with the proposed offer by the Company (the "Exchange Offer") to exchange up 
to $145,000,000 aggregate principal amount of its outstanding 9 1/2% Series A 
Senior Subordinated Notes Due 2007 (the "Old Notes") for a like principal 
amount of its 9 1/2% Series B Senior Subordinated Notes Due 2007 (the 
"Notes") and to exchange up to $169,317,000 aggregate principal amount at 
maturity of its outstanding 10 1/2% Series A Senior Subordinated Discount 
Notes Due 2007 (the "Old Discount Notes") for a like principal amount of its 
10 1/2% Series B Senior Subordinated Discount Notes Due 2007 (the "Discount 
Notes" and, with the Notes, collectively referred to herein as the 
"Securities").  The Old Notes were issued and the Notes will be issued 
pursuant to an indenture by and among the Company, the Guarantors and Harris 
Trust and Savings Bank (the "Trustee") dated June 17, 1997 (the "Note 
Indenture").  The Old Discount Notes were issued and 



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August 27, 1997
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the Discount Notes will be issued pursuant to an indenture by and among 
Company, the Guarantors and the Trustee dated June 17, 1997 (the "Discount 
Note Indenture" and, with the Note Indenture, collectively referred to herein 
as the "Indentures").  The Notes will be jointly and severally guaranteed on 
a senior subordinated basis (the "Note Guarantees") by the Guarantors, 
according to the terms of the Note Indenture.  The Discount Notes will be 
jointly and severally guaranteed on a senior subordinated basis (the 
"Discount Note Guarantees" and, with the Note Guarantees, collectively 
referred to herein as the "Guarantees") by the Guarantors, according to the 
terms of the Discount Note Indenture.  

     As such counsel, we have examined, among other things, (i) the Registration
Statement on Form S-4 to be filed by the Registrants with the Securities and
Exchange Commission (the "Commission") on the date hereof to register under the
Securities Act of 1933, as amended, the issuance of the Securities and the
Guarantees, (ii) the Indentures, (iii) the forms of the Securities and 
(iv) the forms of the Guarantees.  The Securities, the Indentures and the 
Guarantees are sometimes collectively referred to herein as the "Securities
Documents."  We have examined the proceedings and other actions taken by the 
Company and the Guarantors in connection with the authorization, execution and
delivery of the Indentures and the issuance of the Securities and the Guarantees
thereunder.  We also have made such other inquiries and examined, among other 
things, originals or copies, certified or otherwise identified to our 
satisfaction, of such records, agreements, certificates, instruments and other
documents as we have considered necessary or appropriate for the purposes of 
this opinion.

     In rendering this opinion, we have assumed:

          (i)   The Guarantees have been duly authorized by all necessary 
corporate action on the part of Ex-Cell Manufacturing Company, Inc. 
("Ex-Cell") and, when issued and delivered in connection with the Exchange 
Offer in the manner described in the Registration Statement, will be legally 
issued and delivered by Ex-Cell, to the extent such matters are governed by 
the laws of the State of Arkansas;

          (ii)  The due and valid execution and delivery of the Indentures by 
the Trustee, and that the Indentures constitute the legal and binding 
agreements of the Trustee; and

          (iii) The genuineness of all signatures, the legal capacity of all 
natural persons, the authenticity of all documents submitted to us as 
originals, the conformity to original documents of all documents submitted 
to us as certified or photostatic copies and the authenticity of the originals
of such latter documents.

     Based upon the foregoing and in reliance thereon, subject to the
qualifications, exceptions, assumptions and limitations herein contained, and
subject to receipt by the Company and the 



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August 27, 1997
Page 3


Guarantors from the Commission of an order declaring the Registration 
Statement effective, we are of the opinion that:

          1. The Notes, when issued and delivered in exchange for the Old 
Notes in the manner described in the Registration Statement and when executed 
and authenticated as specified in the Note Indenture, will be legally issued 
and will constitute binding obligations of the Company.

          2. The Discount Notes, when issued and delivered in exchange for 
the Old Discount Notes in the manner described in the Registration Statement 
and when executed and authenticated as specified in the Discount Note 
Indenture, will be legally issued and will constitute binding obligations of 
the Company.

          3. The Note Guarantees of each of the Guarantors, when issued and 
delivered in connection with the exchange of the Old Notes in the manner 
described in the Registration Statement and when the Notes and the Note 
Guarantees have been executed and, in the case of the Notes, authenticated, 
as specified in the Note Indenture will be legally issued by each Guarantor 
and will constitute binding obligations of each Guarantor.

          4. The Discount Note Guarantees of each of the Guarantors, when 
issued and delivered in connection with the exchange of the Old Discount 
Notes in the manner described in the Registration Statement and when the 
Discount Notes and the Discount Note Guarantees have been executed and, in 
the case of the Discount Notes, authenticated, as specified in the Discount 
Note Indenture will be legally issued by each Guarantor and will constitute 
binding obligations of each Guarantor.

     The foregoing opinions are also subject to the following additional
qualifications, exceptions, assumptions and limitations:

          A.   We render no opinion herein as to matters involving the laws 
of any jurisdiction other than the United States of America, the State of New 
York and, only with respect to (i) the due authorization, execution and 
delivery of the Securities by the Company and (ii) the due authorization, 
execution and delivery of the Guarantees by each of the Guarantors other than 
Ex-Cell, the General Corporation Law of the State of Delaware.  This opinion 
is limited to the effect of the present state of the laws of the State of New 
York, the United States of America and, to the limited extent set forth in 
this paragraph, the General Corporation Law of the State of Delaware, and to 
the facts as they presently exist.  We assume no obligation to revise or 
supplement this opinion in the event of changes in such laws or the 
interpretations thereof or in the event of changes in such facts.
 



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          B.   Our opinions set forth herein are subject to (i) the effect of 
any bankruptcy, insolvency, reorganization, moratorium, arrangement or 
similar laws affecting the enforcement of creditors' rights generally 
(including, without limitation, the effect of statutory or other laws 
regarding fraudulent conveyances and transfers or preferential transfers and 
distributions by corporations to their stockholders) and (ii) general 
principles of equity, regardless of whether a matter is considered in a 
proceeding in equity or at law, including, without limitation, concepts of 
materiality, reasonableness, good faith and fair dealing.  Without 
limitation, we express no opinion as to the ability to obtain specific 
performance, injunctive relief or other equitable relief as a remedy for 
noncompliance with any of the Securities Documents.

          C.   We express no opinion as to the effect on the enforceability 
of the Guarantees against any Guarantor of any facts or circumstances that 
would constitute a defense to the obligation of a guarantor or surety, unless 
such defense has been waived effectively by such Guarantor.

          D.   We express no opinion as to the validity, binding nature or 
enforceability of provisions in the Securities Documents providing for 
indemnification or contribution.

     We hereby consent to the filing of this opinion as an exhibit to the 
Registration Statement, and we further consent to the use of our name under 
the caption "Legal Matters" in the Prospectus forming a part of said 
Registration Statement.  In giving this consent, we do not admit that we are 
within the category of persons whose consent is required under Section 7 of 
the Securities Act of 1933, as amended, or the Rules and Regulations of the 
Commission promulgated thereunder.

                              Very truly yours,

                              /s/ GIBSON, DUNN & CRUTCHER LLP