Board logo

Using plywood to attach grp body
Replicar328 - 12/5/21 at 06:16 PM

With the help of Martin Batho I've discovered that my BMW328 replica bodywork fits a standard Locost chassis. Such a great discovery, I thought I'd have to design my own chassis from scratch. But how to attach the body to the chassis? My thinking is that plywood panels screwed to the tubular frame would work - for example one sheet attached behind the seats, rising up to meet the bodywork, and two perpendicular sheets to the back would locate the whole rear end firmly. I could probably weld on some kind of lightweight skeleton to achieve the same, but I prefer the plywood (marine ply?) approach which is easier to do and is more within my skill set.

Does anyone have experience of doing similar, and would the IVA inspectors accept this to be safe?

Thanks
Adrian


Mr Whippy - 12/5/21 at 06:56 PM

I suggest looking at home built boats using grp skinned ply construction. Nothing wrong with wood used in the structure if used correctly. The JBA Falcon I built had wooden sills covered in GRP along with various ply bonded in to the structure to stiffen it up.

I'd definitely only use Lloyd's approved marine grade ply. It's not all that expensive and I buy mine from Robbins Timber. It comes stamped with the Lloyd mark, the Robbins Elite is the type I use, perfect for a car.


Replicar328 - 12/5/21 at 07:14 PM

Many thanks, some really good advice. And it looks like Robbins Timber can advise on suitable adhesives. No doubt more costly than B&Q plywood, but worth doing it right


Slimy38 - 12/5/21 at 08:14 PM

Consider the original Locust car as well, that was a wooden bodied seven. Do a search for a build diary or two?


gremlin1234 - 13/5/21 at 06:14 PM

nothing wrong with ply in car construction, in many ways it can be viewed as 'resin bonded wood', or even 'wood reinforced plastic'.
if you look at the regulations, there is virtually nothing saying about materials used, apart from they must be suitable.
the MOT regs refer to corrosion, not specifically rust etc and can include wet or dry rot, or even woodworm!

you won't even need marine ply, since its unlikely to need the continuous salt water submersion capability. (unless you are building an amphicar )

also since these will not be structural panels, you have even more freedom.


SJ - 14/5/21 at 09:12 AM

Use epoxy resin and glassfibre to skin the ply. Epoxy can also be used for bonding - East Coast fibreglass are great for this stuff.


Replicar328 - 15/5/21 at 10:01 AM

Thanks everyone, all good inputs. I'm feeling a lot more confident about using plywood now
Adrian