Personal buildPart 1 of 2Drawing 4.1 of 37

The carbon seat

I went from a plywood box and a lump of clay to a forged carbon shell in eight days. Along the way the clay plug cracked, about four hours after I smoothed it.

StatusSeat and rig built August 2023. Second rig photographed April 2024
MethodPlywood buck, carved foam, clay plug, hand laid forged carbon
TimelinePlywood box to demolded shell in eight days
ShopA home garage, hand tools and an open mold
Not recordedSecond rig's build date, materials and current status

Sheet 02 of 05/The plug

Making the plug

The shape came together in three low tech steps. I carved a plywood box to that drawn line, packed it with foam, and then built it up and smoothed it in clay.

A plywood box filled with rigid foam carved into a seat curve, with brown clay packed into low spots — *PL 03*The box filled with expanding foam, then carved back to the drawn profile and packed with clay.

A smoothed brown clay seat plug set into a wooden frame in a garage — *PL 04*The clay plug smoothed out. Every part of the seat's shape gets set here.

Sheet 03 of 05/What broke

The clay plug cracked

About four hours after I smoothed the clay plug, it cracked all over. I had to fill it and sand it flat again before I could pull a mold off it.

Close up of a clay seat surface covered in a dense network of drying cracks — *PL 05*Four hours later the clay had dried and crazed all over, so I had to fill and skim it before I could pull a mold.

Sheet 04 of 05/Mold and part

Out of the mold in eight days

I pulled a mold off the plug and pressed chopped carbon and resin into it by hand. The shell came out on 15 August, eight days after I first cut the plywood.

Black chopped carbon fiber and resin pressed into a blue seat mold on a wooden frame — *PL 06*Chopped carbon pressed into the mold by hand. Forged carbon uses loose tow instead of woven cloth, so there's no weave to work around on a curve this deep.

A rough black carbon seat shell just removed from its mold, white release residue on the surface — *PL 07*Out of the mold and still covered in release agent, 15 August 2023.

Close up of a glossy black forged carbon surface with a swirling marbled fiber pattern — *PL 08*The surface up close. The randomly oriented tow gives forged carbon its marbled look.

Sheet 05 of 05/The rig

Building a frame around the seat

By 26 August the seat was bolted to a timber frame, with the wheelbase mounted for a first fit. Later the finished rig got pedals, a monitor arm and a fitted fabric cover over the shell.

The carbon seat bolted to a rough timber frame in a garage with a sim racing wheelbase attached — *PL 09*The seat on a timber frame on 26 August 2023, with the wheelbase mounted for the first fit.