How to Make Carbon Fiber Parts – Mouldless Method!
Easy Composites has done an excellent video showing how to make carbon fibre parts without using a mould. Making carbon fiber parts without a mould has benefits and negatives. The video below goes through the entire process and below the video I’ve made a list of the key steps in the process.
Why Mouldless?
Fast & Cheap
No special tools
Problems
Strength, weight and accuracy not as good as using a mould.
Step-by-Step GUIDE – Mouldless Making of Carbon Fiber Parts
This is a summary of the above video with the relevant time stamps.
Step 1 – Build Foam Block, 2:02
Build block of polystyrene foam (black insulation foam) by gluing sheets together expanding polyurethane adhesive
Step 2 – Templates 2:49
Create cardboard templates to help guide your cutting of the foam.
Cut with saw
Use opposite side of template to get shape right. 4:57
Step 3 – Sanding
Sand block to shape.
Step 4 – Release Film 5:46
Cover shape with release film (vac bag material) and use spray adhesive to keep in place.
Slight wrinkles okay
Step 5 – Layup 6:20
Peel Ply first layer.
Cut peel ply to size
Use peel ply to cut carbon to size
In video they want 1mm thickness of final part, 3 layer of 210g twill
Mix resin. Resin weight = cloth weight
Apply resin to release film
Apply peel ply
Wet out peel ply
Add carbon fibre
Wet out
No excess resin on surface
Brush and spreader
Cut to size/edges if needed with shears. Shear in Actetone after for cleaning
Step 6 – Opposite Layer (if layering in two stages)
Smooth and sand edges of first layer. Second layer will key into edge of first layer. 120 Grit.
Same process but with oversized pieces.
Peel ply may need trimming to get good fit with mould
IMPORTANT. Peel ply should not overlap carbon from first layer
Step 7 – Sanding
Light sanding to remove high spots and nibs
Step 8 – Clear Coat (Coating Resin, not laminate resin) or Bondo Body Filler
Paint on, even thin coats, thick as possible before it starts to run.
Leave until slightly tacky (3 hours ish)
Repeat coat
Step 9 – Flat Surface
Sand down to smooth finish (120 grit)
Reapply coating resin
Sanding 400 Grit > 1000 Grit > 2000 Grit > Compound Polishing
A lot of sanding using this method.
Step 10 – Holes
Cut out any holes required.
Remove foam from inside
Remove peel ply and release film
Rebate for hatch/lid. VM100 adhesive to bond 0.75mm carbon strip to inside edge
Issues with Final Carbon Fibre Piece
Waves, ripples through carbon. Drape not as flat as if moulded.
Weight 3.15kg this method, 1.8kg if resin infused.
Making Carbon Parts (Without Mould) – Summary
In some way making carbon fiber parts without a mold is easier, in other ways not so easy.
The biggest issue with making carbon parts without a mold is the amount of sanding needed. And sanding when carbon fiber and foam is involved can get very, very dusty.
The time saving aspect is solely down to not having to make a strong mould that can be used over and over again.
For one piece, making carbon fiber parts without a mould might be the way to go. But I’d say if you need to make more than once piece, making a mould is probably a time saver on the whole.
