Plug and Mold Construction 



 Building and Preparing the Plug or Pattern
        1.    The plug can be made out of just about anything.
           2.    Low density materials, such as foam (LBI 370), will limit the amount of molds to be taken off the plug, usually one, sometimes
                  two.
           3.    The plug should be as defect free as possible to minimize the amount of work done on the mold.
           4.    Any work done on the plug will affect the outcome of the mold and ultimately the part – so be very careful in modifying the plug.
           5.    Finally, after a smooth finish is obtained (A fine sanded 1000 grit Four Seal (LBI 48-9001G) finish  makes an excellent plug finish),
                  begin to wax the plug with a mold release wax (LBI TR-102).  6-8 coats are necessary, buffing after each coat.  Allow the wax to
                  fully cure (20 min.) between each coat.  The last coat should be left for considerably longer to ensure all solvents and vapors
                  have dissipated.  To ensure  a proper release of the mold spray on several thin mist coats of PVA that can be washed off with 
                  warm water later.
           6.    The plug is ready.

Building the Mold
        1.    Begin by spraying 2 coats of Tooling Gelcoat (LBI 304) at least 20 mils thick.  Let the gel coat “gel” in between coats.  This means
                  that the gelcoat will be tacky, but will not come off on yours figures when leaving a finger print.
           2.    Immediately (while second coat is “gelled”) lay up a backing layer of ¾ oz Mat (LBI 7550).  This layer is crucial to keep the gelcoat
                  from hardening and backing away from the plug and to secure the shape of the mold.  The ISO Resin (LBI 302) or Tooling Resin 
                  (LBI 33540) is an excellent mold resin.
           3.    Let this layer of backup mat sit for 2-3 hours if using the tooling resin or 6-8 hours if using the Iso Resin and continue this trend
                  between layers.  For the Tooling Resin application, after 4 layers have been applied it is possible to lay 2 layers at a time to achieve
                  final thickness and strength.
           4.    When laying up your mold, be sure to add sufficient  layers to the mold flanges to ensure adequate stiffness.  This will help in
                  removing the part as well as enabling vacuum bagging or vacuum resin infusion.
           5.    Let the three layers of 1.5 oz Mat (LBI 1550) cure completely, sand and continue.
           6.    You can also use woven roving (LBI 2450, 1850, 4550) in your mold for additional strength.  Make sure that the woven is far enough
                  away from the Tooling Gelcoat to not print  through and is sandwiched between two layers of 1.5 oz Mat (LBI 1550).
           7.    When the desired thickness and strength are obtained let the entire mold cure.

Building the Support for the Mold
        1.    While the mold is still attached to the plug, begin constructing a support for the mold.  This support can be made out of wood
                  or metal.  Tape the supports to the mold with 2-4 layers of laminate depending on the strength and stiffness required.
           2.    The mold supports must keep the mold from distorting or flexing during the lay up process. 

 Popping the Mold and Breaking it in
         1.    Use polyethylene wedges evenly and carefully applying pressure to release the mold from the plug.  Last chance to make
                   any modifications to the mold surface before break in and the lay-up of the first part.
            2.    To break in the mold, wet sand and buff to achieve a smooth glossy surface. – apply 6-8 coats of mold release wax
                   (LBI TR-102) and buff each time.  You should be looking at a very glossy surface.  Refer to step 5 in plug construction.
            3.    Spray a mist coat of PVA for the first few parts molded to ensure release. 
            4.    You are now ready to begin making parts with your new mold.