<PAGE>

                                                                    EXHIBIT 3(a)
                          CERTIFICATE OF INCORPORATION

                                       OF

                                  ASTREX, INC.


The undersigned,  a natural person,  for the purpose of organizing a corporation
for conducting the business and promoting the purposes hereinafter stated, under
the  provisions  and  subject  to the  requirements  of the laws of the State of
Delaware  (particularly  Chapter 1, Title 8 of the Delaware Code, as amended and
supplemented,  which is hereinafter  referred to as the "General Corporation Law
of Delaware"), hereby certifies that:

     FIRST: The name of the corporation (the "Corporation") is Astrex, Inc.

     SECOND:  The address,  including  street,  number,  city, and county of the
registered  office of the  Corporation in the State of Delaware is 32 Loockerman
Square,  Suite L-100, City of Dover,  19901, County of Kent; and the name of the
registered  agent of the Corporation in the State of Delaware at such address is
The Prentice - Hall Corporation System, Inc.

     THIRD:  The  purpose of the  Corporation  is to engage in any lawful act or
activity for which  corporations may be organized under the General  Corporation
Law of Delaware.

     FOURTH: The Corporation shall be authorized to issue the following shares:
<TABLE>
<CAPTION>

Class                                  Number of Shares                      Par Value
-----                                  ----------------                      ---------
<S>                                       <C>                                 <C> 
Common Stock                              5,200,000                           $.01
Preferred Stock                             200,000                          $5.00
</TABLE>

     FIFTH: The name and the mailing address of the incorporator are as follows:

<PAGE>

Name                                        Mailing Address
----                                        ---------------
Michael Harvey                              342 Madison Avenue
                                            New York, NY 10173

     SIXTH: The Corporation is to have perpetual existence.

     SEVENTH:  The number of directors of the  Corporation  shall consist of not
less than five

(5) and not more than nine (9) members.

     EIGHTH:  Whenever a  compromise  or  arrangement  is  proposed  between the
Corporation  and  its  creditors  or  any  class  of  them  and/or  between  the
Corporation  and its  stockholders  or any class of them, any court of equitable
jurisdiction  within the State of Delaware may, on the  application in a summary
way of the  Corporation  or of any  creditor  or  stockholder  thereof or on the
application of any receiver or receivers appointed for the Corporation under the
provisions of Section 291 of Title 8 of the Delaware Code or on the  application
of trustees in  dissolution  or of any receiver or receivers  appointed  for the
Corporation  under the provisions of Section 279 of Title 8 of the Delaware Code
order  a  meeting  of  the  creditors  or  class  of  creditors,  and/or  of the
stockholders or class of stockholders of the Corporation, as the case may be, to
be summoned in such  manner as the said court  directs.  If a majority in number
representing  three  fourths in value of the  creditors  or class of  creditors,
and/or of the stockholders or class of stockholders of the  Corporation,  as the
case may be, agree to any compromise or arrangement and to any reorganization of
the  Corporation as a consequence of such  compromise or  arrangement,  the said
compromise or arrangement  and the said  reorganization  shall, if sanctioned by
the court to which the said  application  has been  made,  be binding on all the
creditors  or class of  creditors,  and/or on all the  stockholders  or class of
stockholders,  of  the  Corporation,  as  the  case  may  be,  and  also  on the
Corporation.

     NINTH:  No  director  shall  be  liable  to the  Corporation  or any of its
stockholders  for monetary  damages for breach of fiduciary  duty as a director,
except  with  respect to (1) a breach of the  director's  duty of loyalty to the
Corporation  or its  stockholders,  (2) acts or  omissions  not in good faith or
which  involve  intentional  misconduct  or a  knowing  violation  of  law,  (3)
liability under Section 174 of the Delaware


<PAGE>

General Corporation Law, or (4) a transaction from which the director derived an
improper personal benefit,  it being the intention of the foregoing provision to
eliminate the liability of the Corporation's directors to the Corporation or its
stockholders  to the  fullest  extent  permitted  by  Section  102(b)(7)  of the
Delaware General Corporation Law.

     TENTH:  The  Corporation  shall,  to the fullest  extent  permitted  by the
provisions  of  Section  145 of the  General  Corporation  Law of the  State  of
Delaware,  indemnify  any and all persons  whom it shall have power to indemnify
under said section from and against any and all of the expenses, liabilities, or
other matters referred to in or covered by said section, and the indemnification
provided for herein  shall not be deemed  exclusive of any other rights to which
those  indemnified  may  be  entitled  under  any  Bylaw,  agreement,   vote  of
stockholders or disinterested  directors or otherwise,  both as to action in his
official capacity and as to action in another capacity while holding office, and
shall  continue  as to a  person  who  has  ceased  to be a  director,  officer,
employee, or agent and shall inure to the benefit of the heirs,  executors,  and
administrators of such a person.

     ELEVENTH:  The Corporation  reserves the right to amend,  alter,  change or
repeal any  provision  contained in this  certificate  of  incorporation  in the
manner now or hereafter  prescribed by law, and all rights and powers  conferred
herein on  stockholders,  directors  and officers  are subject to this  reserved
power.

     IN WITNESS  WHEREOF,  the  undersigned  hereby  executes  this document and
     affirms  that the facts set forth  herein are true under the  penalties  of
     perjury this 23 day of November, 1992.


                                                  /s/ Michael Harvey
                                                 ---------------------------
                                                      Michael Harvey
                                                      Sole Incorporator

<PAGE>

            Certificate of Amendment of Certificate of Incorporation
                                       of
                                  ASTREX, INC.




          It is hereby certified that:

          1.   The   name   of   the   Corporation   (hereinafter   called   the
               "corporation") is Astrex, Inc.

          2.   The  certificate of  incorporation  of the  corporation is hereby
               amended by striking out Articles  Fourth and Seventh  thereof and
               by  substituting  in lieu  of said  Articles  the  following  new
               Articles:

          " FOURTH:  THE CORPORATION  SHALL BE AUTHORIZED TO ISSUE THE FOLLOWING
     SHARES:
<TABLE>
<CAPTION>

        CLASS OF SHARES                        NUMBER OF SHARES                          PAR VALUE OF SHARES

<S>                                                <C>                                          <C>  
       COMMON STOCK                                15,000,000                                   $0.01
       PREFERRED STOCK, SERIES A                      200,000                                   $5.00
       PREFERRED STOCK, SERIES B                   10,000,000                                   $0.01
</TABLE>


     THE SPECIFIC POWERS,  RIGHTS,  PREFERENCES,  DESIGNATIONS,  QUALIFICATIONS,
RESTRICTIONS AND OTHER  CHARACTERISTICS OF EACH SERIES OF PREFERRED SHARES SHALL
BE AS DETERMINED BY DUE RESOLUTION OF THE BOARD OF DIRECTORS."

                                       And

     "SEVENTH:  THE NUMBER OF DIRECTORS OF THE CORPORATION  SHALL CONSIST OF NOT
LESS THAN FOUR (4) AND NO MORE THAN NINE (9) MEMBERS."

     3. The amendments of the certificate of incorporation herein certified have
been duly  adopted in  accordance  with the  provisions  of  Section  242 of the
General Corporation Law of the State of Delaware.


Signed and attested to on August 8, 1997.



                                                /s/ Michael McGuire
                                                -------------------------------
                                                    Michael McGuire, President

Attest:

/s/ Irene S. Marcic
-------------------
Irene S. Marcic, Secretary
--------------------------