Weight Watchers - Forged Carbon Fiber

[Bitza]

Hi all just thought this might be of some interest to someone? My first attempt but easier than I had anticipated. The pics show the making of the mold as well as the final item. I used room temperature cured resin, with a combination of chopped fiber and directional fibers (ribbon strands) for improved strength. Tests show that even just chopped forgings with the same shape are stronger than aluminium, but lighter. I also cast in the pivot bush, and added the pedal stub with Permabond ET5429 epoxy adhesive. The finish is as it comes, a gloss finish is a possibility but I may well simply go for silver. Weight saving will be about 50% for the carbon portion, but the bushes I've used are pretty chunky giving me a saving of only 20+gms. But of course it now means that my heap has something in common with the latest Lamborghinis.

[Mr Gazza]

Teflon/Nylon bushes?

[Bitza]

Good suggestion, have to confess that I just hadn't realised/considered how heavy phosphor bronze bushes would be. But when I handle the gear shift pedal, I can feel that the bush really is all the weight.

[Mr Gazza]

Delrin was suggested to me by Darren as a potential material for Headlamp rings. It turned out to be unsuitable for that and more expensive than what I already use, but I think it would be ideal for the lever bush as it is self lubricating if I recall correctly.
I'm sure Nylon would be fine on a low stress part like that though.
You might even be able get one off the shelf based on the id.

Is the peg cf too? Or aluminium?

I'm just interested if you have a bleed hole in your mould press, for surplus resin and air to escape, or if you carefully weigh out just the right amount of resin?

I like it and I'm sure you will find a few more bitz and pieces to make now..

[Mr Gazza]

Just googled "Delrin bushes" and a vast multitude came up, so I'm sure you could get something the right size for under a fiver.
Also found a material I hadn't heard of before that sounds interesting with probably more choice of bush sizes.


igus® iglidur® FDA Bushes are available in a choice of 3 materials (iglidur® A180, A200, and A500). The bushes require no lubrication. The appropriate iglidur® material to select depends on application:

iglidur® A180 is suitable for general/waterproof use within environments where foodstuffs or drugs are present, and where low water absorption properties are required
iglidur® A200 is also suitable for foodstuff environments (in direct contact with food), where dirt needs to become embedded, and where low to medium load applications apply
iglidur® A500 is the choice of bush material to select where high temperature, chemical and high load resistance is required. iglidur® A500 bushes are also suitable for use within foodstuff environments, and offer good abrasion resistance.

Leading companies across the globe specify Delrin® acetal homopolymer from DuPont for high-load mechanical applications such as gears, safety restraints, door systems, conveyor belts, healthcare delivery devices, and other demanding products and parts. Delrin® acetal homopolymer (Polyoxymethylene POM) is the ideal material in parts designed to replace metal. It combines low-friction and high-wear resistance with the high strength and stiffness such applications require. It provides a wide operating temperature range (-40 °C to 120 °C) and good colorability. Delrin® also mates well with metals and other polymers and offers excellent dimensional stability in high precision molding.

[Bitza]

Originally Posted by Mr Gazza

Delrin was suggested to me by Darren as a potential material for Headlamp rings. It turned out to be unsuitable for that and more expensive than what I already use, but I think it would be ideal for the lever bush as it is self lubricating if I recall correctly.
I'm sure Nylon would be fine on a low stress part like that though.
You might even be able get one off the shelf based on the id.

Is the peg cf too? Or aluminium?

I'm just interested if you have a bleed hole in your mould press, for surplus resin and air to escape, or if you carefully weigh out just the right amount of resin?

Yup peg is turned cf.
No bleed holes, you need to calculate weight of fiber carefully (if the volume is say 100ml/cm3, the density of forged CF is 1.4, so 140 gms, of which 60% needs to be fibers in this example 84gms, the resin volume needs to be well in excess of the finished %, and the excess will be forced out of the gap between the mould halves as you very slowly compress them together giving an opportunity for the fibers to move. Easy Composites do some excellent vids on youtube on the subject, in fact they taught me all I know.

[Jez900ie]

Impressive work Bitza.

[slob]

delrin is fun in the lathe as it starts melting if you get you your feeds and speeds wrong.

[Dukedesmo]

Some years back I was involved with a US based machinery manufacturer, the particular design of this type of machine uses a pair of large bevel gears to turn a drive through 90 degrees (think Ducati style bevel but on a bigger scale), traditionally these would be made from steel but, inevitably they would wear over time.

The US company built their machines with one delrin and one steel gear and we never noticed any wear again plus, it didn't need any specific lubrication either as would the steel on steel.

Not sure how long lasting it would be as a bush but given the small and occasional use a shift/brake pedal gets it should last a good while?

[Bitza]

Couldn't resist getting gearshift fitted, not the easiest thing to photo but here it is anyway.

I'll be looking into the bush issue, igus is a company I've had bits from before (plastic; rose joints, & clevice ends) always take forever to get them. Thanks for the suggestions.

[Bitza]

Just a bit of a conclusion to the thread that at least shows that I do take on board peoples' suggestions. So I re-formed the gear shift using plastic bushes (from Igus Ltd hence the delay/wait), now they feel much lighter, mind you the overall saving on the two pedals is only 105gms. Oh yes have also made a brake pedal to match.
Other possible candidates for reproducing in FCF are: Prop stand, suspension rocker.

[Mr Gazza]

Is that 105gms saving over the original parts or just with the Iglidur bushes over your mk1?
Can't remember if you already made a lighter suspension hoop, but that would be a candidate for FCF.
Also maybe the footrest hangars? Although they are not super heavy anyway.
I notice that you are already using alloy top hats on the mountings instead of the heavy steel shoulder bolts, so you could save another few grams with Ti bolts in the top hats unless they already are.

I'm loving how you have reproduced super light replacement OEM parts. a quick spray over with silver and you'd never know..

[Bitza]

Unfortunately it's an overall saving, at the moment for me 100gm saving is significant, finding the 500gm type savings is pretty difficult without getting into wheels/petrol tank territory. Mind you John Britten made his own wheels.

[Mr Gazza]

I tracked down the Easy Composites videos that you mentioned and watched a few last night. I loved the sensible, informative and untypically non annoying narrator and am left inspired..

[Bitza]

Have a go Gary, it's always exciting seeing what you get out of the mold (assuming that you can get it out).
Generally it's pretty easy to make, getting the materials is especially easy for me as Easy Composites are close by. Forged Carbon Fiber is a nice material but it does have some draw backs, first it doesn't take a thread very well but you could use an insert like a Tappex Trisert-3 made in Ti, bearings need a bit of consideration, not necessarily good in hot conditions depending on the resin used (but people are starting to make con rods from FCF, greatly improve strength if directional fibers (fiber ribbon) incorporated, and doesn't lend itself to large objects because of the even pressure required during the molding/forging process. So making OEM style dual foot peg hanger brackets would be quite difficult and use a lot of resin just to make each mold, so unless somebody else also wanted "rearset" versions like mine I don't think I'll be doing that mod quite yet.