EOI - Kevlar bonnet/boot for 107

[CraigB]

Its been a busy couple of weeks but to cut a long story short i have got to know a guy who had a fibreglass bonnet mould for a 107 from a project he did back 20 yrs or so. On checking with the fibreglass place who is a mate of his, he has lost the mould and so would do a special deal to redo one. Also now he said for all the other rally stuff they do, it is done in kevlar as it is much less prone to breakage, even compared to carbon fibre. I also asked about bootlids, being the other part lightened with alloy in the rally cars/ 500slc.

What i have been asked is to find out if there is more interest to keep the price as low as possible. And of course anyone will want to know the order of price before being able to answer. So the sort of number said to me was potentially say $1000 for a set boot/bonnet, and to me that sounds like a bargain that i would definitely want to take up.

Also i have no knowledge, but if i understood him correctly these kevlar items should be lighter than the alloy or fibreglass. With the bootlid i thought it really could just be virtually a skin, because you could put a couple of brackets and zeus fasten the horizontal part of the boot and then use those rubber clamps at the base like the factory cars had.

Anyway, early days, but if I could get some sort of feel from those that might be interested but with no commitment, that would be great.

[CraigB]

Its had 151 views and no response so I might change the question a bit. I know Greg uses his competitively but is a lovely original car and has alloy bonnet and boot, but does anyone know of any other cars being used competitively? I think Greg's old 350 is and Dkubus Mike does and i will chase him direct. Does anyone think it is a bad idea - open to any suggestions? Every bit of weight lost is more hp on the ground and no doubt why Benz went to the trouble of alloy and there is a fair bit of weight in that big steel bonnet. I'm not asking for any money up front, just looking to work out if i am the only person that will ever be interested in one of these. If you think the boot is not worth the worry then just a bonnet is fine. And i don't have any detail of how strong they will be, what will be used framewise etc and how that fits into the hinge system etc, and you might not like that once i find it out but its no commitment EOI. No probs at all if i'm the only one, but I think that after the initial purchase and the favour called in with this guy, then i imagine the price could rise dramatically to try and recoup mould cost. And that's fine but i guess the only fear is that for only one panel there could be some resistance to do it at all or my price might rise dramatically.

Even if your just thinking about it I would appreciate any response. I just need to let this guy know.

[Djenka018]

I'll play the devils advocate.

Shape replication and structural strength do not have to coincide.
Spending $1000 bucks is not little money for common car mod and worse, it may or may not have a life span of number of times being open.

Would I spend that money?
I probably would, if I was not the pioneer into the field and the structural design is proven good.

So you could say I could be 50/50 into it.

[CraigB]

That's excellent, thanks. Helping me to check what i am asking.

I will put you down as possibility but depends on seeing final product and also final price of course. But still it is possible interest and not zero interest. I think structural strength and shape should be ok but i will double check so thanks for that idea. My understanding is that they have done bonnets for hotrods and motorsport cars for many years, so not just amateurs having a go. But this is second hand info to me.

I'm really keen to get that lighter weight and alloy bonnets I can't imagine being cheap, so i will take a punt anyway and more than happy to be guinea pig. But at least i can give the guy a feel that maybe there could be more interest.

[Djenka018]

Craig,

it is not about the experience or capabilities.
The bonnet is hinged at 2 spots. It may be labour costly to make it self sufficient when raised and to endure some minor wind. This could easily translate into several test models... $$$
Perhaps expectation that it may be say 5kg's, it could get you into direction where hinges become redundant and it would come off as simple as bike fairing.

Again, only plaing devils advocate here, not trying to discourage you or hint that you cannot have a hole in one.


Did you get the projected weight and what would be the weight benefit in kg's?

[CraigB]

Do you have experience with Kevlar? I don't but googling comes up with comments about how much stronger than normal steel, flexibility within the scope of the resins they will set it in - its the stuff that bullet proof vests are made of etc. One person was saying in boat building they use it within the fibreglass layers where they need something of strength and reinforcement, Porsche race cars use it in wings and bonnet. My personal experience is with the factory AMG fibreglass panels on my widebody SEC and they feel way tougher than a steel SEC panel. If they used kevlar instead of the fibreglass matting then it would be even greater strength. I know thats not a bonnet, but compared with the sort of strength in the damaged aluminium bonnet i pulled off the 380sl, strength is not on my mind. I'm all ears but sounds like you are referring to a different material to what i am reading about. Experience is relevant where they have made numerous bonnets and other body panels for rally cars and the guy said 'over time they have found the kevlar works the best - no doubt learnt a long time ago if there are limitations. I will of course ask more questions including weight estimates etc and i know your comments are of a cautionary nature and i appreciate the time people take making comments. But you may know something i don't!

[Djenka018]

Craig,

I was referring to carbon fibre woven sheets and all my exerience of how it fails or endures with (ab)use comes from medical industry where I could see different manufacturers tackle the same problem and produce different results.

Please do not take my thinkering as more than that.

[CraigB]

yes i picked that up in the reading too, that carbon fibre is strong and lighter but past a certain point it is more brittle and breaks. Something i read had laminations of carbon fibre on one side and kevlar on the other. But good questions to ask and see how it goes. But like i said, learning experience and all comments welcome.

[TheMadRacoon]

... the damaged aluminium bonnet i pulled off the 380sl....

Hi Craig, don't want to stray OT too far, but was this a special or do all 380SLs have aluminium bonnets?

I'll have to re-read Greg and Thomas' conversation in the 107 show-us-your-car section where they discuss boot lid weights, but everytime I close my boot I'm surprised at how much weight there is in the lid. Doesn't feel much lighter than the bonnet, though that might just be weak springs.

[CraigB]

My understanding - all post 500 slc alloy engine cars had the alloy bonnet. Only 500sl/slc had alloy boot and why that part is so rare. But also with increased values of the alloy engine cars and what seems like less around, even the bonnets not so easy to find and hence my thinking around the project.

[merc-304]

I cant get my head around that $1k figure for Kevlar..bonnet and bootlid....seems way to cheap

Flick this guy an email : Troy Beros of Composite Eng. Melb /Goldcoast.
Builds racecars from hi tech materials..also has a company called Seagrate - im sure he could advise on the ins and outs of Kevlar etc and is a nice bloke
Troy Beros - instagram and facebook

[CraigB]

My thoughts exactly but i need to look into it. I didn't expect a lot of interest but i have gone through the exercise of asking and can now feed that back and progress to the next stage. At $1k if that is still the price for one set, i am happy to be guinea pig and then can feed back the result. The guy then has the mould and if people like what they see can go direct to him. I think the basis of the price is that he 'owes' this guy a mould and maybe they are really good mates. That's why i posed it as 'if' it was the suggested $1k and not asking for any commitment until more info available. Seems like a bargain to me and so i thought if there was any interest this would help trigger responses. I would have thought maybe double or triple that price and maybe that's what they would market for but i just don't imagine the demand ever being there - only a few nutters like me considering this use for an slc and it still will probably have its ass whipped by Escorts etc., but that's not the point! Talking to someone experienced in f/g he said it is easier to do a mould that you just turn out a few, but if production is for larger numbers then it is a bit more work.The question i think was just to see how much work to put into mould - if there was demand worth the extra effort that he would recoup over time. I just had to check.

But thanks for all the tips and advice and will keep this contact in mind once i get more info and can maybe run it past him for confirmation.

[merc-304]

Popular Mechanics has an article on Carbon Fibre Vehicle Bodys.