Carbon Fiber/Fiberglass

[Xist]

What about titanium threads?

[RustyLugNut]

Originally Posted by Xist

What about titanium threads?

In extreme needs, the strength to weight ratio of Ti is needed. In our motoring world, only F1 racers would consider it. Standard steel and aluminum anchors and pass through load transfer points would not add much weight to the car structure.

[serialk11r]

Originally Posted by Xist

What about titanium threads?

Aluminum has a better specific yield strength (in 7xxx series alloys at least), but has worse fatigue characteristics. However I don't think many people are concerned with a fatiguing car chassis, and even less for body panels.

In F1 I imagine they care about the stiffness a little more which is why they use titanium rather than aluminum. Generally though if you have any kind of sane budget titanium should only be used on critical components like valves and the reciprocating assembly, where you need all of strength, lightweight, fatigue resistance, stiffness, and high temperature performance. Aluminum accomplishes strong and lightweight for much less money.

[redpoint5]

No reason to even talk about CF door replacement. It will never happen because it's too expensive for too little weight saving.

Working with fiberglass and CF is extremely difficult, and paying a fabricator to lay it up would cost a small fortune in both parts and labor.

If you want to save weight, buy a motorcycle. If you want to save weight on doors, get a Jeep.

[RustyLugNut]

Originally Posted by redpoint5

Working with fiberglass and CF is extremely difficult, and paying a fabricator to lay it up would cost a small fortune in both parts and labor.

If you want to save weight, buy a motorcycle. If you want to save weight on doors, get a Jeep.

Look up the cost of standard weave 5 oz. cloth in carbon fiber. You can find it on the market for discounts of 30 USD for a linear yard, 60 inches wide. Expensive in comparison to common glass fiber cloth, but not beyond the reach of the home fabricator. The skill is not that much more difficult than standard glass fiber work with only a few additional safety requirements. I taught my son how to use it when he was 12. He and his cousins constructed skateboards, drum shells and trim inserts for his Mercedes (when he was 15). If you want to design in it, many undergrad reference books are understandable by those with a good technical background.

And, applications such as motorcycles are ideal as the smaller parts size means smaller costs and the small weight saved results in tremendous performance increases.

[oldtamiyaphile]

Originally Posted by Xist

What about titanium threads?

Ti isn't as strong as people think. Grade 5 6Al-4V is the highest grade commonly available and is only suitable to replace grade 8.8 steel bolts.

Higher grades are available, but due to the difficultly or machining these are hard to find and extraordinarily expensive.

UFI is my dieting car and has some Ti and Alu hardware. Whenever a part comes off I do what I can to lighten it.

[redpoint5]

I'm pretty good with my hands, but my first attempt with fiberglass was a disaster. I spent about $150 in materials to make a mold of a kitchen sink, and had nothing but problems. Problems with bubbles, problems with getting the glass to conform to the contour of the sink, problems with the epoxy setting up too quickly, problems with the glass wanting to stick to my hands more than the sink, problems getting the PVA to coat uniformly, etc.

I'd hate to think how difficult fabricating a part more complex than a sink would be. I wasn't even attempting to make a sink; only needed to obtain the negative image of the sink so I could use it as a form in a concrete counter-top/sink.

I also once tried to repair a crack in the plastic fairing of my motorcycle with fiberglass, and that sucked too. I'm done trying to work with the evil substance. 3D printing for the win.

[RustyLugNut]

Originally Posted by redpoint5

I'm pretty good with my hands, but my first attempt with fiberglass was a disaster. I spent about $150 in materials to make a mold of a kitchen sink, and had nothing but problems. Problems with bubbles, problems with getting the glass to conform to the contour of the sink, problems with the epoxy setting up too quickly, problems with the glass wanting to stick to my hands more than the sink, problems getting the PVA to coat uniformly, etc.

I'd hate to think how difficult fabricating a part more complex than a sink would be. I wasn't even attempting to make a sink; only needed to obtain the negative image of the sink so I could use it as a form in a concrete counter-top/sink.

I also once tried to repair a crack in the plastic fairing of my motorcycle with fiberglass, and that sucked too. I'm done trying to work with the evil substance. 3D printing for the win.

I worked at my Uncle's body shop when I was 12 and have been working with steel, aluminum and plastics since then. I have worked in the trades and continue to dive into the "dirty stuff" because I enjoy it and have a knack for it.

However, with that being said, with the right guidance and training, most anyone can perform basic mold making and part layup in their own garage. It just takes some thought, technique and patience. Nothing untoward. Modern materials and techniques make it even easier.

My late mother often made fun of the fact that anything you need to know about anything could be found on YouTube. Fiber Reinforced construction is one of them. I urge you to get out and try - something smaller than the kitchen sink though!

[redpoint5]

Originally Posted by RustyLugNut

However, with that being said, with the right guidance and training, most anyone can perform basic mold making and part layup in their own garage. It just takes some thought, technique and patience. Nothing untoward. Modern materials and techniques make it even easier.

I'm used to quickly learning how to do most things, and tend to give up just as quickly on the few things that don't come so easily (Spanish, Creative Writing, Dancing). After this encouragement, I'll give it another go sometime when I need to fabricate something strong. I'm still giving up on creating a sink mold though!

[niky]

In the end, it's less the ease or difficulty than it simply not being worth it in terms of weight savings, if the end-goal of those savings is merely fuel economy.

It's easy enough to find savings without drastically altering the body. Smaller battery, spare tire delete. Aftermarket fixed bucket seat in place of that heavy, steel-framed couch you're sitting on now.

Then there's all that un-necessary sound insulation goop spread out over the trunk, the firewalls, and under the carpet. There's a good thirty pounds of the stuff, I'd wager.

Then the wheels. A good lightweight set of alloys will make a much bigger difference than a little weight shaved at the doors.

And when you finally do get to the body... you can replace the side impact beams and even the front bumper (not the plastic bumper cover... but the steel beam behind it) with something lighter if weight is the issue. The glass side windows and power window mechanisms are also pretty heavy stuff you don't really need. Thin lexan sheets will do just as well. There's the hood, the trunk... that heavy exhaust system... running without a muffler isn't all that bad if you keep the stock cats and resonator.

-

Still, I know racers that have replaced every conceivable part with glass-fiber and lexan, and have simply gone ahead and drilled holes in the body for even more savings... of course, they DO have a rollcage to make up for the safety compromise!