How to Laminate and Vacuum Bag a Carbon Fibre Part Using a Vacuum Cleaner

Welcome to our first Easy Composites Instructable!

We're are often asked by customers and our YouTube subscribers whether it's realistic for someone with no experience and no special equipment (or big budget) to make their own carbon fibre parts. We think it is and so we created this project to answer that question.

In this Instructable we'll demonstrate how 'hand laminate' epoxy resin and carbon fibre fabric into a mould to make a basic carbon fibre part. We'll then take this just one step further by explaining how a vacuum storage bag designed to compress clothing, and a vacuum cleaner or hand pump, can be used to 'vacuum bag' the laminate, reducing its weight and improving the surface finish of the carbon fibre part.

We hope this project demonstrates that it's perfectly possible for someone with no experience or specialist equipment to make a good quality, lightweight, custom carbon fibre component for their own projects, at minimal cost.

What You Will Learn

• How to hand laminate carbon fabric and epoxy resin into a mould
• How to vacuum bag the part using household equipment

To follow this tutorial, you will need some sort of mould. In our demonstration, we're using a rigid fibreglass mould made from epoxy resin. You can find full details on how we made the epoxy mould here and read about other materials that can be used to make your mould in the section Suitable Moulds.

We hope you enjoy this Instructable and find it useful. We would love to know what you think and answer any questions you may have in the comments below.

In the tutorial we used the Carbon Fibre Laminating Starter Kit from Easy Composites, but depending on the size of your project you may wish to source the materials separately. Here is a list of the materials, tools and equipment we used:

Materials

• 210g 2x2 Twill 3k carbon fibre cloth
• Laminating resin with fast hardener
• Peel-ply
• Breather cloth
• Mould release wax

Tools & Equipment

• 1" Laminating brush (old paint brushes could be used if they're clean and don't drop bristles)
• Nitrile gloves
• Digital scales (kitchen scales will do fine)
• Demoulding wedge (optional)
• Mixing sticks & mixing cups
• Composites shears/scissors (basic scissors would also be fine)
• Vacuum storage bag (used for compressing cloths and bedding etc.)
• Vacuum cleaner with hose attachment
• A soft cloth or tissue to apply the mould release wax
• Work gloves
• Abrasive paper and a Dremel to trim the part (Dremel is optional, a hacksaw blade could be used)
• Clear polyurethane lacquer (optional - if you need a perfect surface finish)

You may wish to use a different reinforcement, including decorative and hybrid carbon fibre and natural fibres. To view Easy Composites range click here.

When working with carbon fibre and chemicals like epoxy resin, it's important to take appropriate safety precautions. Take the time to download and read the TDS (technical datasheets) and SDS (safety datasheets) for the products that you are using, not only will this keep you safe, it will also help you to get the most out of the materials. Remember, if you're using different materials to the ones we're using in this guide, the handling and behaviour of the product may be considerably different.

General guidance when working with epoxy resin:

• Always wear eye protection when measuring, mixing or laminating with epoxy resin
• Always wear nitrile gloves (not latex)
• Although epoxy resin is almost odourless and has no volatile solvents, always work in a well-ventilated area. If you can't work with adequate ventilation, wear a vapour mask.

General guidance when working with carbon fibre:

• Wear protective gloves when demoulding carbon fibre parts, the edges can be very sharp
• Always wear a respirator when cutting or sanding cured carbon fibre (just the same as you would when cutting/shaping wood)

You can use a variety of mould types. This includes moulds made using a gelcoat and fibreglass backing. However, as this process is using an epoxy based resin, your chosen mould needs to be compatible with epoxy so generally speaking that means moulds made with epoxy resin or vinylester based resins. Most polyester based moulds are not suitable as the epoxy would likely stick to the mould despite using a release agent.

For making simple flat parts, you can also use plastic sheet. Ideally the plastic sheet should be glossy to help with release and final finish. Some plastics resin will naturally not stick to, thus making a release agent unnecessary - this includes polypropylene, HDPE, LDPE, PTFE and Teflon. If you get lucky, you might even find that part of a 'tupperware' tub or food container is the right size or shape for what you want to make.

You can also fold metal sheet, like steel or aluminium, into the shape you need but remember to coat metals thoroughly with release agent.

Generally ensure the mould has no sharp bits on the edges or reverse as these may burst the vacuum bag if you use one. Also the better the mould's surface finish, the better the surface finish on the carbon part. So if possible you want your mould to have a smooth, defect free, high gloss finish. We made this mould in another tutorial which you can watch here.

Before you begin, if you will be laminating your part into a composite mould, make sure you are using a mould that has either an 'epoxy' or 'vinylester' gelcoat; this will ensure that you get an easy and reliable release from the mould.

To prevent the part you're about to laminate from sticking to the mould surface, we begin by applying multiple applications of a suitable release agent. We use the Number 8 Release Wax as follows:

• Using a soft cloth put the wax onto the mould surface - using a swirling motion to achieve a thin film of wax
• Then leave it to 'haze off' for 10-15 minutes
• Now using a cloth, buff the surface all over to get it back to a full polish

Then repeat the same process 5 times - this will ensure that you have a thick, even coat of wax all over the surface of the mould.

Carbon fibre cloth can be easily cut using normal household scissors, however if you are going to be working with carbon fibre regularly then a pair of specialist carbon fibre shears can make the job even easier.

Measure how much reinforcement you will need for your mould and cut out an oversized piece, remember it needs to fit into the mould shape and go over the edges. If you've never handled dry carbon fibre fabric before, it's incredibly delicate; be as gentle as you can, especially near the edges which will quickly fray.

To cut carbon fabric in straight lines, it can help to snip the edge of the fabric and then pull a single tow out; this will give you a guideline you can follow with your scissors.

Your carbon fibre part will need multiple layers (called plies) of carbon cloth. Each layer of the 210g carbon cloth we're using here will add 0.25mm of thickness to the part. We'll use 6 layers to result in a total thickness of about 1.5mm. You can use more or less depending on how much strength your finished part needs to have.

It's now time to prepare the resin for the project. We used EL2 Epoxy Laminating Resin with Fast Hardener, if you are working with a different product make sure that you follow the technical and safety instructions on the product.

To work out how much resin you will need for a wet lay-up, we advise you use the same weight of the amount of fabric you are using plus a small amount extra to account for wastage in the pot and on the brush.

The best way to work this out is to weigh your stack of carbon fabric and then mix up the same weight of resin at the correct product mix ratio.

EL2 Epoxy Laminating Resin is an excellent choice for hand layup of carbon fibre parts, including cosmetic finish parts, because it combines excellent mechanical properties with very good clarity and natural UV resistance. It also offers fast wet-out of reinforcement and minimal air bubbles.

Before handling the resin make sure that you put on nitrile gloves and follow your product safety datasheet instructions on PPE.

Weighing out the resin:

• Turn on your digital scales, place on a mixing cup and press the tare/zero button
• Carefully weigh out the correct amount of resin (part A)
• Press the tare/zero button
• Carefully weigh out the correct amount of hardener (part B)
• Ensure amounts are weighed out accurately - wrong measurements can affect curing times

Mixing the resin:

• Mix the resin and hardener together in a slow and steady motion for the time stated on the product
• Scrape the sides and bottom of the pot every so often to ensure a thorough mix
• Then pour the mix into a 2nd cup and mix again

You are now ready to begin laminating, the EL2 epoxy we used has a pot-life or 'working time' of 10 minutes, but make sure you check your product instructions before mixing.

The trick to hand laminating a carbon fibre part correctly is to treat the reinforcement gently, avoiding dragging it too much with the brush, and also to avoid using excessive amounts of resin which will make the part heavier than it needs to be.

• With a brush apply a thin coat of resin directly onto the mould surface. This is to allow the resin to drive up through the fabric rather than trying to wet-out the fabric from the back. This will also reduce the amount of resin likely to get trapped on the surface
• The first layer of reinforcement to go into the mould will be the cosmetic layer which will be seen on the surface, this is the most important layer and it's worth checking that it is perfect and no loose strands or fibres get trapped between the mould surface and the fabric
• Gently place the fabric centrally into the mould, then working from the centre tack it down on to the resin
• Using a brush without too much resin on it and use a stippling motion, apply pressure on to the fabric which will force the resin below up through the fibres of the fabric
• Don't use brush strokes as it is likely to disturb the weave of the fabric and if you are working on a larger parts it may be worth using a roller rather than a brush
• With the first ply laminated you can now repeat the process for the second layer:

2nd - 6th layers

• Brush on a thin layer of resin all over the previous layer of fabric
• Drape over the layer of fabric and tack it down from the centre, working outwards
• Using a brush with no additional resin on and the stipple/squeegee technique work your way over the fabric to consolidate it
• repeat the process until all the layers of carbon fibre cloth have been laminated into the mould

At this stage, if you didn't want to vacuum bag the part you could just leave it exactly as it is to cure. However, vacuum bagging the part helps to compress the reinforcement against the mould's surface which reduces the chances of any voids or gaps in the corners, and also squeezes out excess resin from the laminate, which reduces the overall weight of the part.

So, if you're following along with the vacuum bagging process, let's find out how cloths storage bags and a vacuum cleaner can be used to vacuum bag this part!

To vacuum bag the part using a vacuum storage bag and vacuum cleaner you will need a storage bag like this and a vacuum cleaner with a hose attachment - make sure you check that the nozzle fits the bag valve. It is also possible buy the vacuum bags with a hand operated vacuum pump; these also work great!

We also need a couple of other special bits of material from the composites world; these being a small piece of 'peel ply' (a tight woven polyester or nylon cloth) and 'breather' (a squashy felt-like material).

Cut out an oversized piece of peel-ply and lay over the part and push into the shape of the part like you did with the carbon. The purpose of this sheet of peel-ply is to provide a membrane that will allow air and resin to pass through into the breather layer, but can later be pulled away from the cured laminate leaving a great surface for the underside of your part.

Next with an oversized layer of breather cloth, drape it over the surface and tuck under. The breather cloth provides the air path for the air to escape under vacuum and also absorbs excess resin from the laminate.

Place the laminated, wrapped part into the vacuum storage bag and then place a smaller piece of breather cloth which touches the part and is positioned under the valve to maintain the airflow and seal the bag.

Using your vacuum cleaner pull a vacuum, checking that the bag goes smoothly around any corners or contours of the part and once a full vacuum has been reached replace the cap and leave the part to reach its initial cure.

The amount of time it will take your part to cure will depend on the type of resin you used (including the hardener speed), as well as the room temperature the part is curing in. For the EL2 laminating resin and AT30 FAST hardener, in a room temperature of 20°C the part will be cured in around 12 hours.

Once the part has fully cured, it can be removed form the vacuum bag and demoulded.

• Remove the part from the vacuum storage bag
• Wearing work gloves to protect your hands from any sharp bits of resin or carbon, get a good grip of the the peel-ply and breather cloth and firmly pull the cloth away from the part
• Using a wedge, prise the part away from the mould
• Trim the edges of the part using a hacksaw blade or Dremel with a cutting disc and finish the edges using abrasive paper

The standard of the surface finish of the part using this process should be very good but if you inspect it closely you may notice a few pinholes - this is normal for a hand-layup, vacuum bagged process.

If you need a flawless finish you can sand (and clean) the surface then either spray apply a 'clear coat' or brush apply a special coating epoxy, such as Easy Composites' XCR Epoxy Coating Resin. Alternatively, for those who have been inspired to start on their journey into composites, more sophisticated processes like 'resin infusion' or 'prepreg', whilst requiring more equipment and knowledge, can produce even better components, straight from the mould.

That's how you can wet-lay and vacuum bag a simple carbon fibre part using a vacuum cleaner!

We hope you have found this Instructable fun and educational and would love to hear any comments you may have or answer any questions in relation to the processes in the project.

This really is a great way to access working with carbon fibre and composite material without the need for expensive equipment or experience, we'll share more projects with you soon!