[Video] Large Scale Mold Making - Making the Negative "Tool"

Step 9 Applying Glass and Resin Application

Here is where it's nice to have a few people. Well, 2-3 at least. One to mix resin, one to apply glass and resin, one to remove air bubbles. The first step of glass applying is to cover the plug with fresh resin -- not mixed with any thickening agent. Don't mix it into the thickened resin "gel coat" - otherwise you ruin it's purpose of providing a glossy surface.

Just smear it over with a brush or paint roller (whatever is available at the time). For the next part - you'll want to use a paint roller.

Now it's time to break out the glass. Chopped fiberglass is easy to tear because there's no weave. So, tear off large chunks and place them on your plug. The "wet" surface should hold it quite well. Apply some resin (you don't need to completely cover the entire piece now) and keep adding glass until the entire surface is covered. Once the plug is covered -- roll on some resin. Then, use a roller to remove air bubbles. Look closely inside the/beyond the glass for bubbles and gently roll them away.

The rollers we're using are designed just for the purpose of removing air bubbles from fiberglass.

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Flange
We need a flange! The flange goes around the entire mold. So be sure to let the chopped fiberglass go down onto the MDF - this is why you applied wax and PVA to the edge near the plug. This is also why you built up some of the "gel coat" at the edge of the plug/MDF - easy fiberglass transition. Be sure to remove air bubbles from here and make sure that the edge is nice and even.

Repeat this - non stop for as many layers that you need to get the desired strength. We're doing 4 - and it used up 5 gallons of resin. This mold is going to weigh around ~50 lbs! But, it will have an indefinite lifetime (well, very long service life) as long as it's kept out of UV radiation.