In order to achieve a perfect laminate and ideal fibre to resin ratio, the industry often uses the vacuum wet bagging method. This method involves applying a vacuum to remove excess epoxy from the laminated fabric, resulting in an ideal resin-to-resin ratio.
In this article we explain step-by-step how to make a surfboard from expanded polystyrene (EPS) and laminate it with carbon fabric using the vacuum wet bagging technique. The step-by-step plan includes the following five steps:
- Stap 1. Preparation
- Step 2. Carbon lamination
- Step 3. Vacuum pulling
- Step 4. Removing the vacuum bag
- Step 5. Applying second layer of carbon fabric
Wet bagging is widely used for reinforcements in motorcycle fairings, model and competition boats, boats, surfboards, spoilers, centreboards, rudders and car parts.
What do you need?
- Vacuum pump PS9/80 + vacuum hose
- Universal Epoxy (slow)
- Bleeder
- Perforated film for wet bagging
- Vacuum film
- Sealant tape
- Fabric of your choice (e.g. carbon fibre)
Auxiliary materials
- Laminating spatulas
- Mixing cups
- Mixing spatulas
- Kitchen scale
- Nitrile gloves
- Velor roller + paint roller frame
In the video above, Herman and Alexander explain step-by-step how to cover the surfboard made of EPS with carbon fabric.
Step 1. Preparation
Think of a way for yourself to work conveniently. Expect epoxy to drip off as you work, so cover the floor.
Make sure that the surface you are going to cover is rough and clean. If necessary, sand the surface briefly. Is the surface very light? Then there is a chance that you will see this through the carbon fabric. If this is the case, you can first spray the surface black with acrylic paint.
Step 2. Carbon lamination
Cut the carbon fabric generously to the size of the surface. Do this carefully because carbon twill fabric in particular frays and twists quickly. Lay the fabric neatly on the surface.
We will now laminate the carbon fabric. In the video we use a universal epoxy resin with slow hardener so that we have enough time to go through all the steps. After pouring the epoxy, the assembly must be packaged so that the vacuum can be drawn.
The epoxy should be at room temperature and dosed at 150 grams per square metre using the correct mixing ratio (2 parts by weight of base and 1 part by weight of hardener). Mix both components thoroughly and do not forget to include the edges and bottom of the mixing bowl.
The epoxy is then poured onto the carbon cloth and spread with the lamination spatula. The epoxy is then applied to the carbon fibre and spread using the lamination spatula. Do not press too hard because you will damage the fabric and the epoxy may start to foam.
In this way, multiple layers of fabric can be laminated one after the other.
Step 3. Vacuum pulling
After laminating the carbon fibre, it is important to place the surface under vacuum.
Cut perforated foil and bleeder to size and cover the surface with it. In the video we sprayed the bleeder and perforated foil with spray adhesive and bonded them together. This is easier to work than with loose perforated foil.
Then cut the vacuum foil generously so you can use it to wrap the entire workpiece. It is important to cut generously, to be able to make pleats.Then cut the vacuum sheet generously so you can use it to wrap the entire room. It is important to cut wide, to be able to make pleats.
Wrap the entire work piece with the vacuum foil and seal the bag with sealing tape. Press firmly so there are as few air leaks as possible. Glue a piece of bleeder around the end of the vacuum hose so that it does not close under the vacuum bag. Run the vacuum hose through the end and tape it shut.
Turn on the pump and check if the bag is under vacuum. If not, listen carefully along the edges, as you can usually hear air leaking. If there is a leak, press the sealing strip firmly or apply an extra piece to seal it properly.
The PS90 pump has adjustable vacuum. A vacuum of 0.5 bar under pressure is sufficient for this application. Leave the pump running for at least 12 hours. One of the great advantages of the PS90 pump is that it has a buffer, which means that the pump itself is not constantly on and is not subject to unnecessary loads.
Now that the surface has been laminated and is vacuum sealed, it must be allowed to cure for at least 24 hours.
Step 4. Removing the vacuum bag
After the surface has completely hardened, the vacuum bag can be removed. Carefully cut the vacuum bag, perforated foil and bleeder. The combination of bleeder and perforated film is easily removed from the laminate.
Step 5. Applying second layer of carbon fabric
After applying the first layer of carbon, you can apply the laminate to the other side of the surfboard. Mark where the next layer of carbon should come, secure it with tape and repeat steps 1-4 described above. After curing, the carbon fabric can be cut along the tape, so that a very tight transition is obtained.
More information about wet bagging?
In the aforementioned step-by-step plan, you were able to read how you can coat a carbon fibre substrate using the vacuum wet bagging technique. We wish you much success in your project! If you still have questions after reading this article, please do not hesitate to contact our customer service. We are happy to help you!
