I decided to try building a buck, as getting my hands on a nosecone was going to take a while. I'd reached the point where much of my progress was blocked. I think it's a good idea to leave building the scuttle until the lines of the nosecone can be followed through the hood to the scuttle, so I wanted to wait until I had the nosecone in hand.
I'm not particularily interested in working with fiberglass, the fumes and the mess something that I prefer to avoid (much to the relief of my neighbours). It also needs warmer temperatures to do properly, which limits the time of year that I could progress. In all likelyhood I will purchase a nosecone, but I wanted to build a buck just to get the feel of working with it. Since it was all throw away, I wanted to limit the expense and trouble and time involved.
I settled on building a buck from 1/8" hardboard - it took only 1 sheet, about $9 cdn, not bad. From that I built the buck and back panel for the scuttle.
Note that a real buck would be better made from 3/4" or thicker board, perhaps plywood or MDF to save money. Also note that the buck I did build was pretty much useless to me. I consider it educational and interesting, but it was a wrong turn none the less. I learned that with an 8 1/2" high nosecone (about where S/T join the side rails), a 11" high scuttle clears the engine bits better than a 10" one. About 8" is the lowest that I could go with my 4AGE mounted 2" below the chassis.
To build the buck, I first drew a pleasing nosecone shape over my chassis model using Turbocad. Once I had the shape I'd like, I added some additional plane slices that followed the design in 3 dimensions. I printed many copies of the needed views on a cheap inkjet printer, taped the sheets together, cut them out with about 1/2" to 3/4" clearance around the cut lines, then glued them to the hardboard. It was then easy to cut the templates out with a jigsaw. The 1/8" kerf left by my table saw blade made easy work of the split lines to fit the pieces together.
See Fibre Glast, be sure to visit the info center at that site, which contains a wealth of information related to building fiberglass parts and molds.
One approach would be to fill the buck (which becomes therefore a plug) with foam pieces (glueing them in place), then shave/sand it to shape using the hardboard templates as a guide. Cover it with a thin coat of body filler or plaster, carefully smooth. This male, sacrificial plug could then be used to build a female master fiberglass mold, from which your nosecones could be made. This of course would really only be practical if you were making many nosecones. Fibre Glast's technical document on "Mold Construction" covers this topic very well.
A second alternative would be to make the plug slightly smaller than the final shape, and fill it with glued in foam pieces as above. Cover this plug with fiberglass. Carefully remove the plug, then fiberglass the inside if necessary for strength. This will result in a reasonably good nosecone, requiring a fair amount of work to finish, but probably less than making a mold. Fibre Glast's technical document on "Moldless Composite Construction" covers this topic very well.