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                                                                   EXHIBIT 4.11


                                    GUARANTEE

                            Dated as of May 14, 2004

GREENFIELD COMMERCIAL CREDIT (CANADA), INC.

      THIS GUARANTEE, effective as of the date accepted by you, sets forth the
terms and conditions upon which the undersigned (whether one or more in number,
referred to herein as "we," "us" or "our" and whom, if two or more in number,
shall be jointly and severally bound) agree to Guarantee certain loans made by
you:

      1.    UNDERLYING FACTS.

            (a) You have agreed to extend financing facilities to STEELBANK INC.
(the "Seller") as evidenced by a Factoring and Security Agreement dated May 14,
2004 (the "Factoring Agreement") and documents executed therewith (the "Finance
Facilities").

            (b) You require as a condition of entering into the Finance
Facilities that we execute and deliver this Guarantee.

      2.    AMOUNT OF GUARANTEE. In order to induce you to enter into the
Finance Facilities, we absolutely and unconditionally guarantee to you the due
and prompt payment and performance of any and all indebtedness, liabilities and
obligations of Seller to you whether now existing or hereinafter purchased or
incurred, direct or indirect, absolute or contingent, secured or unsecured,
matured or unmatured, joint or several, including without limitation, all
indebtedness evidenced by the Finance Facilities, whether for principal,
interest, fees, expenses, costs of enforcement, including reasonable attorneys'
fees, or otherwise (the "Obligations"). In addition, we shall pay you all costs
incurred, including reasonable legal fees, in enforcing payment and performance
of this Guarantee.

      3.    YOUR AUTHORITY. You may from time to time without notice to us
and/or without our consent and upon such terms and conditions as you may deem
advisable without affecting this Guarantee:

            (a)   release the Seller, any maker, guarantor, surety or other
                  person liable for payment of all or any part of the
                  Obligations;

            (b)   make any agreement extending or otherwise altering the time
                  for or the terms of payment of all or any part of the
                  Obligations;

            (c)   modify, waive, forbear, compromise, release, subordinate,
                  resort to, exercise or refrain from exercising any right you
                  may have hereunder, or under any of the Finance Facilities;

            (d)   accept or decline additional security or guarantees of any
                  kind;

            (e)   endorse, transfer or assign any promissory note or any other
                  security to any other party;

            (f)   accept partial payment or payments on account of the
                  Obligations;

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            (g)   make further or additional loans or give or extend credit to
                  or for the benefit of the Seller;

            (h)   release, settle or compromise any of your claims against the
                  Seller or any other person, firm, corporation, guarantor, or
                  account debtor whose obligation is held by you as collateral
                  security for the Obligations;

            (i)   release or substitute collateral, guaranties or guarantors;
                  and/or

            (j)   amend the Finance Facilities, whether or not such amendment
                  increases the likelihood of our liability under this
                  Guarantee.

      4.    OUR WAIVERS. We unconditionally and absolutely waive:

            (a)   any obligation you may have to protect, secure or insure any
                  of the collateral given to secure the payment of the
                  Obligations or to ensure the Seller's compliance with any such
                  obligation imposed on the Seller under the Finance Facilities;

            (b)   any right to participate in any of the collateral given as
                  security for the payment of the Finance Facilities;

            (c)   notice of your acceptance of this Guarantee;

            (d)   any right to notice of presentment, notice of demand for
                  payment, notice of non-performance, protest, notice of
                  protest and notice of dishonor, notice of non-payment and
                  notice of partial payment;

            (e)   any right to notice of any default under any of the Finance
                  Facilities or in the performance of any of the covenants and
                  agreements contained therein or in any instrument given as
                  security therefor;

            (f)   any defense, offset or claim the Seller may have against you;

            (g)   any limitation or exculpation of liability on the part of the
                  Seller whether contained in the Finance Facilities or
                  otherwise;

            (h)   the right to notice and the right to consent or object to the
                  transfer or sale by the Seller of any collateral or any
                  diminution in value of any collateral or any release of any
                  collateral;

            (i)   any defense, offset or claim of lack of commercial
                  reasonableness in the method, manner, time, place and terms of
                  the disposition of collateral given as security for the
                  Obligations;

            (j)   any failure, neglect or omission on your part to realize upon
                  or protect the Obligations or any collateral given as security
                  therefor;

            (k)   any right to insist that you prosecute collection of the
                  Obligations or resort to any collateral given as security for
                  the Obligations or to proceed against the Seller or against
                  any other guarantor or surety prior to enforcing this
                  Guarantee; provided,

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                  however, in your sole discretion you may, either in a separate
                  action or in an action pursuant to this Guarantee, pursue your
                  remedies against the Seller or any other guarantor or surety,
                  without affecting your rights under this Guarantee;

            (l)   any right to participate in or direct such action or
                  proceeding in 4(k) above;

            (m)   any right to notice of advances made to Seller under the
                  Finance Facilities;

            (n)   any right relating to notice or any order, method or manner of
                  application of any payments on the Obligations; and/or

            (o)   any right to insist that you disburse the full principal
                  amount of the Finance Facilities to Seller or the order,
                  method, manner or amounts disbursed under the Finance
                  Facilities.

      5.    OUR REVOCATION. This Guarantee shall remain in full force and effect
and be binding upon us and shall inure to your benefit until thirty (30) days
after the date this Guarantee is expressly terminated by notice in writing
delivered personally to or received by registered mail by you at 316 - 20 Queen
Street West, Toronto, Ontario M5H 3R3, attention the Chief Financial Officer,
with a copy to 300 E. Long Lake Rd., Suite 180, Bloomfield Hills, Michigan
48304, attention the Credit Manager, or such other address you specify in
writing to us; provided, however, that this Guarantee shall remain in full force
and effect regardless of such termination with respect to all Obligations in
existence on the date of such termination (including any subsequent extension,
renewal, modification, amendment or compromise thereof and all subsequently
accruing interest and other charges thereon) until all such Obligations are
fully satisfied and paid to you. In the absence of any termination of this
Guarantee in accordance with the provisions of this Section 5, we agree that
until all Obligations and our obligations under this Guarantee are satisfied,
this Guarantee shall remain in full force and effect notwithstanding that from
time to time the Seller may be free from all Obligations.

      6.    ADDITIONAL WAIVERS. We will not assert against you and do hereby
unconditionally and absolutely waive all defenses of the Seller and any defenses
we may have against you, including, but not limited to, defenses of waiver,
release, discharge, bankruptcy, statute of limitations, res judicata, statute of
frauds, anti-deficiency statute, fraud, fraudulent conveyance, insolvency, lack
of consideration, merger of claims under this Guarantee with the Obligations,
ultra vires acts, usury, illegality or unenforceability, any defense which,
under principles of Guarantee, suretyship or other applicable law, would operate
to impair or diminish our liability under this Guarantee, any setoff available
against you by Seller whether or not on account of a related transaction, and we
shall be and remain liable for any deficiency remaining after foreclosure of any
mortgage or any security interest securing the Obligations notwithstanding any
provisions of law that may prevent you from enforcing such deficiency against
the Seller.

      7.    EFFECT OF BANKRUPTCY. Our liability shall not be affected nor
impaired by any voluntary or involuntary dissolution, sale or other disposition
of all or substantially all of the collateral or assets of Seller, receivership,
insolvency proceeding, bankruptcy, assignment for the benefit of creditors,
reorganization proceeding, arrangement, composition or readjustment of, or other
similar event or proceeding affecting the Seller or any of its assets and that
upon the institution of any of the above actions, at your sole discretion and
without notice thereof or demand therefor, our obligations hereunder shall
become due and payable and enforceable against us, whether or not the
Obligations are then due and payable.

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      8.    MARSHALING OF ASSETS. We waive any defense or claim relating to any
obligation you may have to marshal the collateral or other assets of the Seller
for our benefit, and we agree that you shall be under no duty to marshal the
assets of the Seller for our benefit or any third party.

      9.    ABSOLUTE AND UNCONDITIONAL. No act or thing, except for payment in
full, which but for this provision might or could in law or in equity act as a
release of our liabilities, shall in any way affect or impair this Guarantee.
This shall be a continuing, absolute and unconditional Guarantee, and our
liability on this Guarantee shall be immediate. You may have immediate recourse
against us for full and immediate payment and performance of the Obligations, or
any part thereof, at any time after the Obligations have not been paid or
performed when due (whether by acceleration or otherwise). Subject to Section 5
hereof, this Guarantee shall remain in full force and effect until the
Obligations have been paid in full notwithstanding any change or modification of
our relationship with the Seller which exists as of the date hereof.

      10.   SUBORDINATION AND REPRESENTATIONS AND WARRANTIES. All indebtedness
and liability now or at any time or times hereafter owing to us by the Seller is
hereby subordinated to the Obligations and any payment of indebtedness or
liabilities of the Seller to us shall be held by us in trust for you, segregated
from other funds, and shall, immediately upon our receipt, be turned over to you
in the exact form received by us (duly endorsed to you, if required), to be
applied against the Obligations, whether matured or unmatured, in such order as
you may determine.

      11.   SUBROGATION. We waive any claim or other right which we may now have
or may hereafter acquire against the Seller or any other person that is
primarily or contingently liable on the obligations that arise from the
existence or performance of our obligations under this Guarantee, including,
without limitation, any right of subrogation, reimbursement, exoneration,
contribution, indemnification, any right to participate in any claim or remedy
you may have against the Seiler or any collateral security therefor, which you
now have or hereafter acquire, whether or not such claim, remedy or right arises
in equity, or under contract, statute or common law, save and except upon
execution and delivery of a General Release pursuant to Section 18 of the
Factoring Agreement. If any amount shall be paid to us contrary to the terms of
this Section 11, such amount shall be held by us in trust for you, segregated
from our other funds, and shall, immediately upon receipt by us, be turned over
to you in the exact form received by us (duly endorsed to you, if required), to
be applied against the Obligations, whether matured or unmatured, in such order
as you may determine.

      12.   SETOFF. Upon the occurrence and continuation of a Default (as
defined in the Finance Facilities), we hereby authorize you at any time and from
time to time to set off and apply any deposit held and any other indebtedness at
any time owing by you to us or for our account against our Obligations and
liabilities to you.

      13.   REINSTATEMENT. This Guarantee shall continue to be effective or be
reinstated, as the case may be, if at any time any payment of all or any part of
the Obligations is rescinded or must otherwise be returned by you upon the
insolvency, bankruptcy, reorganization, liquidation or dissolution of the Seller
or otherwise, all as if such payment had not been made. We hereby indemnify and
hold you harmless from and against all costs and expenses you may incur,
including reasonable legal fees, in connection with the defense of a bankruptcy
preference action, fraudulent conveyance action, lien avoidance action, or other
action relating to your right to retain amounts previously paid to you in
respect of the Obligations, and for all costs and expenses you may incur
relating to the Obligations or the security therefor during any applicable
redemption period following the foreclosure of any mortgage or security interest
in any collateral, including but not limited to, taxes and insurance costs in
respect of such collateral, whether or not the Seller would be liable to you for
such costs and expenses.

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      14.   YOUR RELIANCE. We acknowledge that this Guarantee is executed in
order to induce you to extend the financing facilities with the intent that you
will rely upon it in making and disbursing the Finance Facilities with the
knowledge that you would not do so but for execution of this Guarantee.
Disbursement of any part of the Finance Facilities, without any further action
or notice, shall constitute conclusive evidence of your reliance hereon.

      15.   REPRESENTATIONS AND COVENANTS. Each of the undersigned hereby
represent and agree as follows:

            (a)   we are meeting our current liabilities as they mature; our
                  financial statements furnished to you fairly present our
                  assets, liabilities and financial condition; since the date of
                  such financial statements, there have been no material adverse
                  change in our financial condition; there are not now pending
                  any material court or administrative proceedings or any
                  undischarged judgments against us, and no federal, provincial
                  state or other tax liens have been filed or threatened against
                  us, nor are we in default or claimed default under any
                  agreement for borrowed money which has not been waived. A
                  description of any waived defaults is disclosed on Schedule A.

            (b)   we agree to immediately give you written notice of any
                  material adverse change in our financial condition, including
                  but not limited to litigation commenced, tax liens filed,
                  defaults claimed under our indebtedness for borrowed money or
                  bankruptcy proceedings commenced by or against us. Upon your
                  request, we agree to deliver to you timely annual financial
                  statements for the preceding year and supporting federal,
                  provincial state or other tax returns, and at such reasonable
                  time as you request, to furnish our current financial
                  statement.

            (c)   we are fully aware of the financial condition of the Seller
                  and deliver this Guarantee based solely upon our own
                  independent investigation and in no part upon any
                  representation or statement made by you with respect thereto.
                  We are in a position to and hereby assume full responsibility
                  for obtaining any additional information concerning the
                  Seller's financial condition as we may deem material to our
                  obligations hereunder. We are not relying upon nor expecting
                  you to furnish us any information in your possession
                  concerning the Seller's financial condition.

            (d)   neither the Seller nor the Guarantors is in default under any
                  material agreement, contract, lease or other instrument to
                  which the Seller or the Guarantors is a party and no event has
                  occurred which, with the giving of notice or the passage of
                  time or both, will become an event of default thereunder.

            (e)   there is no litigation or proceeding pending or threatened
                  before any court, agency, tribunal, arbitration board or any
                  other body which has or could have a material adverse effect
                  upon the condition, either financial or otherwise, of the
                  Seller or the Guarantors Principal or the ability of the
                  Sellers and the Guarantors to perform its or their obligations
                  under any of the Factoring Agreement or any of the documents
                  executed and delivered in respect thereof.

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      16.   SECURITY. The performance of our obligations under this Guarantee is
unsecured.

      17.   MISCELLANEOUS.

            (a)   No right or remedy conferred upon or reserved to you under
this Guarantee is intended to be exclusive of any other available remedy or
remedies but each and every remedy shall be cumulative and shall be in addition
to every other remedy given under this Guarantee, or the Finance Facilities, or
as may now or hereafter exist at law or in equity. No waiver, amendment, release
or modification of this Guarantee shall be established by conduct, custom or
course of dealing, but only by an instrument in writing duly executed by you.

            (b)   Whenever the context requires or permits the singular shall
include the plural, the plural shall include the singular and the masculine,
feminine and neuter shall be freely interchangeable.

            (c)   This Guarantee is delivered in and made in, is executed with
respect to and shall in all respects be construed pursuant to and governed by
the laws of the Province of Ontario.

            (d)   This Guarantee and each and every part hereof, shall be
binding us and our heirs, administrators, representatives and executors and
shall inure to your benefit, and your successors and assigns, including each and
every assignee of any part or all of the Finance Facilities.

            (e)   This Guarantee may be executed by one or more of the parties
hereto on any number of separate counterparts and all of the counterparts taken
together shall constitute one and the same instrument.

            (f)   This Guarantee constitutes the joint and several obligation of
each guarantor of the Obligations, including the undersigned, and shall be fully
binding upon and enforceable against any or all of such parties or persons and
their sole and separate estates. Neither the death nor release of any guarantor
of the Obligations shall affect or release the joint and several liability of
any other person or party. You may at your option enforce this Guarantee against
one or more or all of the guarantors of the Obligations; provided you shall not
be required to resort to enforcement against each and every guarantor of the
Obligations and the failure to proceed against or join each and every of the
guarantors of the Obligations shall not affect the joint and several liability
of each of the guarantors of the Obligations.

            (g)   This Guarantee is intended by us as a final expression of our
agreement and is intended as a complete statement of the terms and conditions to
which we are bound.

      18.   WAIVER OF JURY TRIAL. OUR LEGAL COUNSEL HAS ADVISED US THAT (a)
THERE MAY BE A RIGHT TO A JURY TRIAL IN CONNECTION WITH ANY CLAIM, DISPUTE OR
LAWSUIT ARISING OUT OF THIS GUARANTEE, AND (b) SUCH RIGHT MAY BE WAIVED. AFTER
CONSULTATION WITH OUR COUNSEL (WHICH HAS INCLUDED OUR COUNSEL'S REVIEW OF THIS
GUARANTEE), WE BELIEVE THAT IT IS IN OUR BEST INTEREST IN THIS COMMERCIAL
TRANSACTION TO WAIVE SUCH RIGHT. ACCORDINGLY, WE HEREBY WAIVE OUR RIGHT TO A
JURY TRIAL AND FURTHER AGREE THAT THE BEST FORUM FOR HEARING ANY CLAIM, DISPUTE
OR LAWSUIT, IF ANY, ARISING IN CONNECTION WITH THIS GUARANTEE OR OUR
RELATIONSHIP WITH YOU, SHALL BE A COURT OF COMPETENT JURISDICTION SITTING
WITHOUT A JURY.

      WE GIVE THIS GUARANTEE FREELY AND VOLUNTARILY TO YOU WITHOUT ANY DURESS OR
COERCION. WE HAVE CONSULTED WITH COUNSEL AND WE HAVE CAREFULLY AND COMPLETELY
READ ALL OF THE TERMS AND PROVISIONS OF THIS GUARANTEE.

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                                                BST ACQUISITION LTD.

                                                /s/ Charles A. Vanella
                                                -------------------------------
                                                Name
                                                President

                                                TARPON INDUSTRIES, INC.

                                                /s/ Charles A. Vanella
                                                -------------------------------
                                                Name
                                                President