38 replies to this topic

[TUF 308]

Tiny Posted on Jan 12 2008, 06:39 PM
  How does it go for stiffness compared to the steel bonnet?

Also do you know if it's legal to use a glass bonnet on the street? It's bloody good an an easy weight saving! The way youve done the bracing i think it would be hard to tell!

Stiffness wise it is a bit flexible compared to a steel bonnet but the next one i make ill do some things a bit differently to make it a bit stiffer.

Legality wise i do believe that you have to get them ADR approved dont quite know not that ill be bothering. Like you say its an easy weight saving and thats what my main goal was to make it look like a original bonnet. if i had more time i would have filled and faired the exposed sections of the inner skin so it was smooth and you didnt see the glass fibres.

Also, how does/will it be held down in place when closed, same latch/catch system as now ?

Use standard latch system see photos below

I had a fiberglass bonnet on a Monaro and had to remove the springs because it would nearly take peoples heads off when unlatched.


Can you paint these bonnets black or will that cause them to go soft if left sitting in the sun?

yeah fitted it today the standard springs are just way to strong overkill for a 7kg bonnet will be chasing up some softer ones maybe.

I will be painting my bonnet black(one day). I used a high quality VE resin which has a Heat distortion temperature of 80degress. She'll be right.

What baronvonrot said is true if you want a 2kg bonnet it will cost you shit loads, like anything its getting that last 5% that costs the most. to shave 3-4 kilos of a bonnet like mine is going to cost the big bucks.

Pre Preg would be the go for super lightness, have used this stuff at work really cool stuff. Had to make a Composite Pressure Vessel for the collins submarines. was all made out of prepreg was fun for the first couple days until the novelty wore off.

Fitted:

[Tiny]

Thanks heaps for the info! and again thanks for the detailed photos! Awesome project!

[boblhslr]

Hi tuf308
If you were going to make others for other poeple how much would they cost.
Thanks

[Toranamat69]

If the NCOP rules ever come in, they allow fibreglass for non structural panels such as bonnets and bootlids. The fibreglass will need to be min 3mm thick too.

Pre 73 cars you can do the whole single piece fronts because they don't have front impact requirements - don't you just love the logic behind these rules:))

Talking to my engineer, it is a real grey area in QLD with the current regulations.

I am saving my cookies to buy an fibreglass LX bonnet (soon hopefully) so I am interrested in price and more importantly - how straight it is.

M@

[GML-31]

should have used black gel coat... saved you painting for a while

Edited by GML-31, 13 January 2008 - 10:18 PM.

[TUF 308]

hey guys really appreciate the comments

If you were going to make others for other poeple how much would they cost.
Thanks

Dont Really know at this stage i dont want to commit to anything at this stage as i dont really have the time, had to do mine over my christmas break. I wouldnt like selling them unseen to. id like people to see what there getting before i sold them. if you know what i mean?

The moulds do need a bit of rework, the inner skin mould needs some sanding and a few things touching up.

The moulds were made off a really straight bonnet i bought so the bonnet came out really good.

should have used black gel coat... saved you painting for a while

Was thinking about doing that but deceided against as that would have been a extra 1 or so kilos added to the weight. being the first one i wanted to see how light i could get.

Well done on the Pics and full walk through, now maybe the front quarters and bumpers and youve got yourself a new business.

thanks mate was thinking about doing bumpers a while back, be very easy just never got around to finding a nice straight one. Althought if i was going to, i would make the bumper brackets out of fibreglass as well because they weight more then the bumper bar itself. that would be easy to do as well. Anyone know the weight of bumper bar plus brackets?

awsome stuff, now can you make me a hatch lid?

hehe

[makka]

Baron, I wasnt doubting your knowledge on CF, I was just throwing in my opinion.
the problem with the stuff we did is we made it to be fast and light, not pretty, except our frames, they were sex on wheels! I will see if I can dig up some pics from somewhere.

TUF, did you handle the bonnet without the inner skin? did the inner skin add much stiffness and much more weight?

also, about the bumpers, I personally think you would be better making the brackets out of aluminuim

Edited by makka, 19 January 2008 - 09:44 AM.

[Toranamat69]

I weighed my original steel LX front and rear bumpers which are also fitted with the rubber strip.

The front bumper complete with brackets was 15kg and the rear bumper with brackets was 12kg.

My f/g front bumper with new alloy brackets including all fasteners is 2.5kg, a saving of 12.5kg and my f/g rear one with brackets is 1.5kg so another saving of 10.5kg.

I can't remember the exact figure for the brackets themselves but from memory the front brackets were about 4.5kg each and the rear brackets about 2.5kg each.

I like the alloy brackets because you can polish them up really nicely rather than having to paint them.

They were pretty easy to make too - especially the rear ones.

M@

[TUF 308]

Wow I didnt realise that they weight that much hey. So i guess thats next then, bumpers. You right about the brackets 2, alloy be much better.

TUF, did you handle the bonnet without the inner skin? did the inner skin add much stiffness and much more weight?

I never got a chance hey makka. The outer skin never came out of the mould until it had the ribs glued on. It would have been very flimsy thou, i only did 2 layers of 450csm, (about 1mm thick). So it defantly needed the ribs on it. in terms of weight the inner skin makes up about 1 third of the total weight. It is 2 layers of 300csm.

I think next time ill play with the idea of a vag baged core.(when i get the time)

Edited by TUF 308, 23 January 2008 - 06:41 PM.