Materials you need:
- A mold, I used MDF but it’s possible to use many different materials like glass, clay and even polyester. The smoother the surface is the better it works. Some materials, like MDF, will have to be coated with a polyurethane resin to seal the pores of the material.
- Synthetic resin.
- Catalyst.
- Release agent.
- Surface tissue.
- Glass fabric. There a many different types of glass fabric, just ask your supplier what is best for your job. Some fabrics are more suited for difficult shapes than others.
- Cleaning fluid, to remove the release agent before painting the fiber glass.
- Polyester filler, to fill up any imperfections.
- Scissors, to shape the glass fabric.
- Putty-knife, to apply the polyester filler onto the fiber glass part you’ve made.
- Industrial mask, sanding the polyester gives a very nasty dust that is dangerous for your health!
- Brush, not a soft one. To apply the resin.
- A measuring beaker
- Sanding paper grid 1200
- Roller, to remove bubbles of air.
- Hypodermic syringe
- Latex gloves
Step one: Preparing your mold
Apply release agent, I used mold release wax, onto the mold with a cloth.
Leave it on for a couple of minutes and wipe it off in a circular motion with a clean cloth. Repeat this step about three times. This step is very important, because you don’t want the polyester to stick to your mold.
Step two: mixing the resin with the catalyst
Pour the resin in a beaker or jug.
Add ~1-3 % catalyst to the resin, use a hypodermic syringe to add the right amount of catalyst.
While adding the catalyst, stir the resin.
BE WARE the catalyst is very corrosive and oxidizing so wear latex gloves!
Stir the resin about two to three minutes. This is very important for the process. The color of the resin changes from blue to yellow/brown.
Step three: applying glass fabric and resin to your mold
Use a brush to apply a thin layer of resin to your mold
Put a layer of surface tissue on the mold. Tap with your brush onto the fabric. You can see the resin come through the fabric.
Add some more resin with the brush if necessary. The resin should be visible all over the fabric.
Sometimes bubbles of air get stuck underneath the fabric, use a roller to remove the air.
When the resin covers the whole surface of the fabric, add a layer of glass fabric and repeat the previous procedure. The more layers of fabric you add. The thicker the polyester gets and the stronger and more rigid it gets. I used about three to four layers of glass fabric and one layer of surface tissue.
Don’t rush things, but you have to know the resin starts setting in about 10 to 15 minutes, depends on how much catalyst you have used, so make sure you are finished with a layer within that time. You can always add one or more layers if you need to, later on. Just wait a couple of hours, mix some new resin and start the process over for the new layer(s) you want to add.
Wait about one to two hours and
cautiously remove the polyester from the mold. You can pull and push to get the polyester from the mold. Just take your time and don’t try to get it off by just pulling in one spot. Pull at several spots/areas to distribute the force evenly. It’s easy to see where the polyester releases from the mold. I found it easier to remove the polyester before it was completely cured. Now you will have to remove the glass fabric that sticks out.
Just use a saw or your Dremel to remove it and
wear your industrial mask! And wear your latex gloves as well, because the dust is very itchy and dangerous. I found it out the hard way.
Step four: fixing any imperfections
Before giving the part a paintjob you will have to apply some bondo for polyester. It’s a paste. It comes with its own catalyst, also a paste. Add about 2% catalyst. Mix small amounts of bondo, because it cures very fast and use a putty knife to apply it. You only need to apply a very thin layer of this bondo. To get smooth finish wet sand the part with sandpaper, I used 1200 grit. Use water with some normal dishwashing detergent to get the best result. Everything smooth? Now wait some days for the polyester to get dry before painting it.
Step five: paintjob
It’s time to give the part a paintjob, but not before you cleaned the part with some cleaning fluid. This cleaning fluid will remove all of the release agent. Ask your paint supplier what paint is suitable for polyester, not every kind of paint can be used on polyester.
This tutorial will be improved as soon as I have some more and better pics. 
