Coachbuilding project on the 1926 Citroen B2 - Faine 412

By: Jon Faine

Presented by

3d car frame 2 3d car frame 2

Faine wrestles with shapes in three dimensions

Do you improvise as you work on your car? Or are you the type who fanatically follows the step-by-step procedures in the manual?

I have revived the coach building exercise on the 1926 Citroen B2. I am making a boat-tail body to go on the farm hack chassis I bought years ago. My car as bought had no structure at all aft of the front seat. Mechanically the old girl was intact and the motor running. I am basing my project on a Citroen B2 ‘Caddy’, of which 300 were made. Rumours persist that at least one example made it to Australia. I am pretending that mine revives the extinct breed. I want to finish the project by 2026 in time for it to get a telegram from the King.

3d -car -frame

It is a typical body style of the time. A high cowl providing cover for the dash panel with minimal instruments, and a wide waist that tapers to a ducktail. In profile, a swage line runs along the horizontal level, and the top deck drops down to meet the flanks at a nice pointy end that overhangs the rear of the chassis. It looks like a chocolate eclair – how very French ! The curves of the flanks are in three dimensions – vertical, horizontal and tapering all at once. There is a transition curve starting somewhere around the door and the B post. It goes from convex at the front to concave at the rear. The profile of the curvature changes as you get closer to the ducktail. Degree of difficulty = 93.5 !!

There are no plans. I’ve been unable to locate any drawings. I do have some photos, and have scaled up some drawings from those. Since I know the size of a wheel and tyre, I can calculate the dimensions of other parts from that. But it turns out the exercise is a whole lot more complicated, and there are zero manuals on how to coach build a boat-tail body from scratch.

3d -car -frame -3

I’m now on my third version of a buck. The first two have been tossed aside as good learning experiences, experiments and trial runs. They were somewhat lopsided and wonky.

I know that I am far from professional, and miles away from the techniques adopted by someone who knows what they are doing. I am literally making it up as I go. I am spending as little money on the buck as I can manage. After all, it is all going to get thrown away.

The buck is cut from MDF with a bandsaw and a jigsaw. The profile, the spine of the buck, is carved from a huge sheet of MDF marked up from a 1:1 drawing, which itself was scaled up on tracing paper, the outline based on a period Citroen factory press photo. I’ve made little wedges to hold the horizontal ribs in place, spaced at 100mm intervals as marked on the spine.

3d -car -frame -5

The tapers – both vertical and horizontal – were guessed by attaching the end of a thin aluminium strip to one end of whatever panel was being carved and then fixing the bow as best as I could with clamps. It gradually came together, and then I decided to create the infill with hardware shop battens, as thin as I could buy. They bend without snapping and adopt a nice gentle curve. I found a great little staple gun that shoots tiny pins to secure the thin strips to the MDF ribs, but the ribbons of timber are too springy and keep popping.

Inspired by the San Francisco Golden Gate bridge, I devised a fastening system that if patented would fill the family coffers and provide the grandchildren with a fortune to fritter away on hedonistic waste. Thin gardening wire is anchored under the floor by a nail and fed upwards through a small hole. Then, under tension, the other end is wrapped around the batten to hold it in place. Cheques – crossed please – can be sent care of the editor.

3d -car -frame -4

Now I have the shape about right, I have made cardboard templates of all the curves in every plane, measured everything twice and taken a million photos. Now the plan is to discard the buck, paint the chassis, then to restore, paint and install all the running gear, stand the chassis on its wheels and bolt on a radiator. Then all I have to do is bandsaw the 60 or 70 hardwood frame pieces and assemble the jigsaw puzzle to create a solid base for skinning in steel.

Piece of cake, ought be done by Christmas. Christmas 2026.

 

Sign up to our free weekly newsletter for more unique car reviews and features plus see the latest unique and classic cars for sale.

Subscribe to Unique Cars magazine
- Print edition
- Digital edition