I'm not an expert, but have dealt in Kayak molds and plugs, and you might 
be better off  making a heavy part(chopper gun or lots of matt, as you are 
effectively making a plug here to modify later) from the existing mold, PVA 
the hell out of the mold surface after waxing til your arms fall off(to 
prevent the new plug from sticking to the old mold), then go through the 
gelcoat and laminating process.  It would be helpful to find out what the 
layup was for the original parts and then multiply that several times so 
you have a very stiff plug to keep it's original integrity.  Since you're 
going to be doing many changes to it, I wouldn't worry about having a 
pretty surface as it's much more important to have the new plug release 
from the old mold.  I'd also be careful when laminating a thick plug as 
that much thickness with normal catalyst concentrations could make a VERY 
warm environment(exothermic heat buildup, I think).  I have a friend in 
Pittsburg Kansas that is an expert in the field, having laminated a 
mahogany wood plug for a commercial 48" city water valve mold that needed 
to spec out within .06"   I could get you in touch with him if you were 
really serious about the project.At 03:15 PM 2/6/2005, jimt wrote:
>On 2/6/05 8:00 AM, "Joe Federici" <joefederici@EARTHLINK.NET> wrote:
>
>On a hightop for my van I have been looking at some of the ones in the
>salvage yards that are on chevy and dodge etc.
>
>For those that work in the fiberglassing,  how hard would it be to maybe
>modify one of those tops.  One I was looking at I figure I could do the base
>trimming with very little difficulty.  The hard part would be a split down
>the center to remove about 1 inch and then somewhere across from one side to
>the other to remove about 6 or 7 inches.
>
>I was thinking 20 gauge aluminum plate (or similar) along the seams from the
>inside with rivets through to plate on the outside at points and then reseal
>everything with fiberglassing kit.  I have done similar on smaller projects
>but never on anything of that size.  Is this doable on that scale?
>
>����������������������������������������
>jimt
>Planned insanity is best.
>Remember that sanity is optional.
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