Porsche 914 Dash Repair via CFRP Wrapping Process Options

[dovsky]

CFRP stands for Carbon Fiber Reinforced Polymer, which is the technical term for what most people refer to as just simply “carbon fiber”. CFRP is a composite material comprised of the carbon fiber itself (in this case in the form of woven fabric) and a formulated resin compound acting as a plasticizer.

In this thread I’ll be showing step-by-step how we (www.compositedimensions.com) were able not only to repair and save a cracked 914 dash, but to also make it look and feel as if it was originally made from CFRP.

Below are a few photos of the dash prior to the repair.





STEP 1 – Crack Sealing. We used a 2-part epoxy putty compound to fill and seal each crack. An unlike most polyester-based body fillers, this compound is compatible with the epoxy resin system used in the later steps.


STEP 2 – Epoxy Based Coat. This base coat provides an ideal black background for the carbon fiber fabric and allows the dash to gain back some of its rigidity at this early stage. After its application, it’s left to reach a “tacky” stage (approx. 4 hours).


STEP 3 – Making Cutting Templates. Carbon fiber fabric is expensive. This particular fabric is $50 per square meter. In order to minimize material waste, cutting templates is a must. This not only saves material but also provides more accurate placement with minimal seems, and eliminates “bridging” on intricate contoured areas. The fabric itself is a high quality 200 grams/sq. meter 2/2 twill 3K.


STEP 4 – Carbon Fiber Wrapping (Dry). While taking advantage of the tacky surface on the base coat, and with the aid of a compatible spray adhesive, the various pre-cut carbon fiber pieces are carefully placed into position. Notice that we also wrapped the visible underside areas.



STEP 5 – Clear Epoxy Resin. Once all the carbon fiber is laid, we applied 3 coats of a specially formulated high viscosity epoxy resin. Minimal sanding in between coats is performed to remove obvious high-spots before allowing the final coat to cure overnight.

All visible areas on the underside are also addressed.


STEP 6 – Sanding (Dry & Wet). The dash was sanded dry using 120 grit paper to remove any remaining high-spots before moving on to wet sanding with progressively finer girt paper (240, 400, 800 and 1200), leaving a smooth satin finish at the end. This is by far the longest process step.

Dash after dry-sanding it with coarse 120 grit paper:

Dash after wet-sanding it with fine 1200 grit paper:


STEP 7 – Finishing. We applied 2 coats of UV-stable high-gloss lacquer. Once cured we then machined-polished all surfaces to achieve a professional finish.







The dash is finally done and ready to be installed back.
Project duration: 2.5 weeks including curing & drying times (epoxy resin and lacquer coats).
Total Labor hours: 45 (most of them spent on surface sanding)

I hope you enjoyed this article. All questions are welcome.

Checkout our other products and services at www.compositedimesnions.com along with our growing 914 Carbon Gear parts catalog where you will find sun visors, center consoles, side mirrors, gauge and trim panels.

Dov

Dov Chartarifsky
CEO – Composite Dimensions
Hameyasdim #62
Zichron Ya'akov
30900, Israel
Tel: +972 (0) 50 4047915
dovsky@bezeqint.net
dov@compositedimensions.com

[Darren C]

Fitting the ashtray would be awkward as the overlay would make the opening smaller. I doubt it would fit without cutting down the ashtray front and spacing out the steel ashtray support.
Also the dash would be over length which would make it harder to fit between the A pillar trims. The gauge panel too needs all the space the original dash offers.
The overlap of your carbon wrap & resin on the underside would also raise & push out the position of this trim when fitted to the dash frame by the thickness of the resin. This would also cause alignment issues getting the fixing studs (at 90 degrees) to locate in the dash frame.
The wrap on the undersides in the door shut area would also push the knee roll down making that hard to fit back.

For the reasons above, this is why a dash cap is cut short at the ends and stops shy of the gauge panel.



As pretty as it looks....Have you tried fitting this in a car yet?

Trust me on this one. A simple retrim of a dash top with vinyl or leather gives you all these fitment issues, so with carbon and resin your making it larger and heading for a poor fit back in the car with little compression ability that you get with vinyl or leather that makes it just possible to get back in.

[dovsky]

Fitting the ashtray would be awkward as the overlay would make the opening smaller. I doubt it would fit without cutting down the ashtray front and spacing out the steel ashtray support.
Also the dash would be over length which would make it harder to fit between the A pillar trims.

For the reasons above, this is why a dash cap is cut short at the ends.

As pretty as it looks....Have you tried fitting this in a car yet?

We've only done one dash, which is now being shipped back to it's owner for fitment. The added thickness is minimal at about ~1mm (CF=0.25mm, resin/lacquer=0.5-0.75mm). In case of any over length/size areas, these can easily be sanded down.