CF: Form vs Function

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OK, I have given my opinion on the subject.

Conclusion apparently is people most of the time will get cf for looks, when you get into larger pieces the cost becomes prohibited or ridiculous.

Top racing teams can afford latest technology on everything and cf is a given, and to them a small investment in their operation.

A chop lay up is not as strong as a hand lay up, and a chop machine does not come cheap. If you want the carbon fiber look go with exactly that since a pure carbon fiber piece unless a small one are a lot of money, The large ones are very expensive and as stated before the quality a lot of times very poor.

I am now experimenting with very high heat fire resistant resin and materials to make pipes and tubing, to me this is just a hobby and as such I am always thinking of new things.

In reference to making 2 or sometimes 3 molds to make a piece it is only necessary on very large pieces and when you have negative angles, like I had to make for corvette front fenders and when I was done you could not tell where the seam was.

Unless for a dedicated car I would not go with either one specially doors .

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[H@xtGSX]

Things have changed a bit, and a lot of people haven't noticed. Especially if you've been working in a particular fashion for a while with tried and true dependable materials. I can totally understand that, and I'm often the same way. If it ain't broke, don't fix it... but...

CF chop is available in bulk, in many strand lengths, for a considerably smaller amount than cloth. You can prepreg your own materials in a bucket. There's no machine necessary. There is however a technique to making an initial backbone layer with a positive/negative pressure mold, and then either using subsequent pressure mold layers or vacuum bagging on more material... OR, there is an injection molding machine that does the type of work like they've been researching at Lamborghini. They, however, are requiring fast, automatic mass production, and no one is going to be buying their machine or design anytime soon. They also incorporate an autoclave curing process. The look is a secondary concern, an optional feature. Chop pieces generally just look a solid grayish black, like graphite. Hand layup with chop isn't really an enticing propostion. You'd need some pretty thick resin to make that work, and putty it on... I haven't heard of it ever being used in hand layup. In a vacuum or pressure mold though, it is MUCH stronger than any hand layup. The resin is the weak point of the matrix, so systems that draw off as much of it as possibly always produce stronger, lighter parts. The trick is being able to apply pressure to wick off the resin and compact the fiber, AND distribute the material evenly. I've cobbled together a makeshift "injection vacuum bag" similar to an infusion system that can get a fairly uniform surface, but it's not fast, it's not reliable, and it's not user friendly... at all. That being said though, the parts we completed and messed around with were still REALLY tough and disturbingly light. They feel "fake", they are so light... and they were ~1/5 the cost. The technical data also shows that in a randomly distributed chop, CF isn't DIRECTIONALLY as strong as cloth is, but overall likely to be much more durable. It's strong in every direction instead of in planes... so you sacrifice either a little strength or a little weight for a pretty huge reduction in cost. I can't estimate what the time consumption difference is yet, but I intend to find out.

I agree on the tabbing statement. My answer to this is basically what you suggest. A 2 piece part with 2 molds that would ultimate be joined for a single finished part. What I haven't tried to do yet is make a hardened mold that would allow something like injection molding under pressure. Maybe like a positive/negative with a vacuum bag like seal inside that'd allow you to fill the gap up under pressure.

It's a little discouraging to hear that your business is drying up GR... I've already committed to at least making prototypes for my own vehicle. I have a lot of good ideas that I think others would like... but money makes the world go 'round...