How To Fiberglass – Mold Layup

My next video.

Information and a demonstration of how I layup one of my molds. Headlight eyelids. Big thanks to Randy Roach(GlasserGlass) for some handy tips and some inspiration to make a vid or two.


I noticed this video has got 7000 views in 2 months so it looks like ill do another one for you all. Considering how many people are viewing this video I thought I would clear up any misunderstanding and give allot more text info here relating to the video.

I only put one wax application on this mold because its an older mold and its been well used. For fresh molds you must put several layers of wax on and I would consider PVA as well if the mold is less then a week old. Always use PVA (or equivalent) on your plug surface before molding.

Ive got allot of PMs about the gun. The gun used in this video is just a very cheap method of spraying gelcoat on some of my smaller molds. For the larger parts, tooling gelcoat or for anything I want precision, I use a HLVP gun with a 3.5mm tip. Most of the time for these small parts I just brush gelcoats, you can get just as good results. When brushing leave longer then usual before resin/CSM, I usually leave it overnight. This is so that any high spots from the bristle streaks have time to fully cure. If you layup over any wet gelcoat you will get alligatoring(crocodiling) reactions on the surface. There is no maximuim time between gelcoat and resin/CSM. Gelcoats do not contain wax which means they will stay tacky and ready for resin for weeks and even months. As long as there isn’t big temp changes (which causes peeling) or dust/debris in the area.

2% catalyst is for a normal day (temperature and humidity). For a hotter day use 1-1.5% and for a cooler day use 2.5-3%. Standard polyester resins don’t require this finesse but for gelcoats it is good to be accurate to avoid any kind of reaction. You should not fiberglass in really cold weather. Catalyst is by weight, and you should buy some cheap kitchen scales and a chemist syringe to measure it correctly.

The mixing cups I use are called heavy duty party cups, made in china. I get them at a local discount variety store (Clarksons Discounts) at a ridiculous 80cents for a pack of 25. They withstand all resins fine and are good for a 300g mix max. Not all plastic cups will hold up to resin, I suggest buying samples of all available cups to you. See which ones work or not then buy more.

225g/sq meter CSM = 0.75oz/sq ft CSM. (Not to be confused with the imperial woven cloth measurement of oz/sq yard)

WAX = Carnauba wax (release agent).
FG = Fiberglass
CSM = Chopped Strand Matte(reinforcement)
PVA = Polyvinyl alcohol (release agent)
Plug = The original item that your creating a mold of.
Mold = A negative replica of the plug, specifically a ‘tool’ mold.

If you want to ask me more questions on a project of yours etc you can contact me on MSN If you add me please tell me your from youtube asap.

Post time: 01-25-2017