JSF-TC

My Feedback: (2)

I'm teaching myself how to build a plug/ mold/ composite model, and starting with some of the small pieces before moving on to the more challenging parts. End result will be a scratch built scale jet.

I'm having problems with the tooling gelcoat when making the mold.

I'm using all Fibreglast products: #186 Black Tooling Gelcoat & #77 Polyester Resin with chopped strand mat glass.

I'm using a mixture of 3D printed ABS and glass covered balsa plugs finished with Duratec Surfacing Primer. Parting planes are made from laser cut foam poster board hot glued together.

I initially tried to make their Fibrelease release agent work, but eventually switched to Partall Wax & PVA for much superior results.

My initial mold attempts resulted in severe wrinkling of the gelcoat which I eventually determined was due to me not applying sufficient gelcoat. Once I measured the surface area and worked out a required volume for the recommended 25 mil (0.6mm) thickness I mostly cured the wrinkling issue.

I must have had at least 6 attempts at a plug for this first part - the last attempt with a calculated volume of gelcoat to give a 1mm thick layer did not have any wrinkles, but I had multiple areas of what I would term shrinkage (as can be seen in the photo with the ruler for scale), which made the mold scrap. I'm thinking this may be from excess gelcoat where it had pooled in the corners.

I have bought a gelcoat spray gun with a 2.5mm nozzle for one last attempt with the polyester gelcoat, but I also plan to try switching to an epoxy-based mold (#1098 Epoxy Surface Coat + System 2000 Epoxy Resin & glass cloth).

Does anyone have any suggestions as to how to improve my results with the polyester tooling gelcoat?

Some views of a successful plug/ mold (with some minor wrinkles, but usable) also attached that give me hope that I'm headed in the right direction.


Thanks

Paul