Hi All,

I,ve now reached the bonnet stage.... Looking at the archives it looks like everyone has merely cut the bonnet to the scuttle and nose cone, has anyone bothered to turn the edge back on itself for a neater finish ?

If so what problems did you encounter.

Cheers Mark

If this is an MK bonnet you shouldn't have to cut anything, it should fit exactly between the scuttle and nose cone.

Rich.

what can be neater than a cut straight edge?

I suspect with bending the edge, you may make a mess unless you have a sheet metal folder and it would need to be done before the bend so it may not fit if you get it wrong. How do you propose to bend it once curved? pliers and the such will mark the metal so read the first sentence

as someon who has recently spent a load of time on a bonnet, it ain't worth it.

As you're building an MK... the bonnet is fibreglass. DON'T BEND IT!!! It is made to size and adjustment of scuttle/nose cone is required for it to fit properly...

If you're referring to manufacturing your own aluminium one - good luck!

Fibreglass bonnets sometimes need trimming. The edge then covered with u trim 9 i got mine from Mac#1). Gosforth VOSA require the edge trim to be bonded on.

Scratch built so I,m making as much as I can.

The reasons for wanting to turn the edge are two fold

1) no sharp edges.

2) It will make the ali more rigid when bent to shape around the scuttle.

I do have access to a sheet metal bender but I do not think flattened out the edges would be straight.

Anyway is no-one else has bothered then neither shall I.

Cheers Mark

I did! Mainly for rigidity. Took it to a metal shop who used a sheet metal folder. The only problem was that despite careful measurement, and marking the edge of the fold, the guy got it wrong. The edge is a couple of mil out. Having made too many bonnets to mention, I've accepted this one as the final one!

In Exterior Projections SVA manual says sheet metal edges must be folded back 180 degrees on themselves (13.3.e). It doesn't really say if this is an exposed edges or any edge.

To be sure I put 5mm beading on all exposed edges (suspension holes etc) including the bonnet front and rear even though it is flush with the scuttle and nose cone.

How long it will stay on after SVA I'm not sure

FRP panels must have a radius not less than 1.5mm. (13.3.k)

[Edited on 26/5/06 by pajsh]

Mark, all edges of my bonnet have a return!

Fozzie
Rescued attachment 1aFozzie.jpg

My first attempt at a bonnet was going to have 180 degree returns at the back and front edges. It's actually very difficult to form these, as the edges are not straight lines, meaning you have to lose or gain metal as you fold it. You can't put a 'snip' in the return either, as when you try to form the curves it will always 'give' where the cuts are.

Eventually I gave up with this, and just fitted some U-trim over the plain edge, which gave a perfectly good result. My advice is, unless you're highly skilled in sheet metalwork (like Fozzie....!) and have the right equipment, forget the returns.

Geoff.