S4 bonnet problem

Post by: **Bitsilly** » Thu Oct 19, 2023 2:48 pm

I have a replacement bonnet for my Sprint but it has a depression in it.
Someone suggested it is missing the bonded in metal support.
I thought that was only on the +2’s.
If there is supposed to be one could some kind person please post a photo?
Or supplier, in fact any help appreciated.
I’m currently looking for an old bonnet to replace the new one but this may sort me out!
Cheers

Post by: **trw99** » Thu Oct 19, 2023 3:34 pm

Anti-depressants should do the job!

My Sprint bonnet has no metal reinforcement across it. I have a vague idea that a good shipwright who does a lot of work with fiberglass, may be able to help sort your problem out. I know a very good one, but on the East Coast, which may not be helpful to you.

Tim

Post by: **Bitsilly** » Thu Oct 19, 2023 3:42 pm

I’m keeping the antidepressants until restoration is complete.
I binned my old bonnet due to fire damage but I’m pretty sure it didn’t have bracing, if it did I would have stripped it off first, so I’d best have another poke around.

Post by: **alan.barker** » Thu Oct 19, 2023 6:07 pm

On a +2 Elan it is a brace NOT bonded but screwed to Bobbins.
On an Elan the Brace is bonded in but NOT Metal as far as i know.
Alan
P.S. i stand corrected, it's metal for the Hook to be brazrd/welded to. For the big Spring to attavh then go to Steering Rack

Post by: **RichardHawkins** » Thu Oct 19, 2023 6:21 pm

My car is a1968 S4 fixed head. The bonnet has some form of stiffener on the underside bonded in place and covered in fibreglass, which looks rather like a single corrugation. I don’t know what the stiffener is made of but it would need to expand at the same rate as the fibreglass bonnet to avoid the bonnet and stiffener tearing apart as the bonnet heats up.

Hope this helps,

Richard Hawkins

Post by: **Lens4** » Thu Oct 19, 2023 8:05 pm

Hi look on eBay for fibreglass rope I’ve got some to replace the rolled cardboard they glass in as supports just soak them in resin with bonnet upside down supported at the edges see if it needs a bit of weight to remove the hollow. Len

Post by: **StressCraxx** » Thu Oct 19, 2023 8:27 pm

The bracing under the bonnet is cardboard tube covered with fiberglass mat. Simple, cheap and light.

Post by: **smo17003** » Thu Oct 19, 2023 9:18 pm

This topic is worth a look as it discusses the bonnet bracing viewtopic.php?f=36&t=24719

FWIW my S4's bonnet is considerably heavier than my S3's as it has the perimeter hoop.

Post by: **Spyder fan** » Fri Oct 20, 2023 7:04 am

Sue Miller used to sell the bonnet bracing hoop separately, I notice in her latest price list that all bonnets are now supplied with the strengthening hoop and spring hook ready bonded in. For approximately £250 this may be your best option.

Post by: **Bitsilly** » Fri Oct 20, 2023 6:05 pm

It was Sue who told me about the bracing when I asked if she had any bonnets!
I will knock up something to support a single corrugation until it sets, cardboard tube probs.
Just need to find some pictures of how to lay it out.
Thanks again all and sorry for delay replying, new phone misbehaving.
Cheers

Post by: **smo17003** » Fri Oct 20, 2023 6:45 pm

Does your new bonnet have the spring hook (you haven't mentioned it)? If it does, then there must already be a perimeter brace as this is what the hook is welded/brazed to.

Post by: **oldelanman** » Fri Oct 20, 2023 7:41 pm

Bitsilly wrote:It was Sue who told me about the bracing when I asked if she had any bonnets!
I will knock up something to support a single corrugation until it sets, cardboard tube probs.
Just need to find some pictures of how to lay it out.
Thanks again all and sorry for delay replying, new phone misbehaving.
Cheers

Couple of photos from the gallery of bracing on S2 and S3 bonnets ..... Brian's (Type 26/36) cars I think.

: S2 BONNET (Copy).JPG (87.89 KiB) Viewed 40252 times

: S3 BONNET (Copy).JPG (102.45 KiB) Viewed 40252 times

Post by: **Bitsilly** » Fri Oct 20, 2023 7:58 pm

smo17003 wrote:Does your new bonnet have the spring hook (you haven't mentioned it)? If it does, then there must already be a perimeter brace as this is what the hook is welded/brazed to.

I’m away at the moment but I don’t think there is any metal work at all.
Is this something else I have to add?
Dave from Lotus Factory may be able to help.

Post by: **richardcox_lotus** » Fri Oct 20, 2023 8:54 pm

S4 and Sprint bonnets do not have that cross bracing. The supporting card/ rope is alongside the side edging (perimeter) stops about halfway along. Ignore the red circles on these photos.