I bought the vacuum pump but havent found time to use it, I need some kind of vacuum switch you can make them from an old vacuum advance apparently

Isn’t the male/female mould system ideal for RTM?

The male/female method will be hard to do at home, as the two moulds need to match up, with exactly the correct gap between, then you need the correct thickness of carbon, too much and where does it go, too little and it’s not in connect. One mould is much easier, and works if you only need one good surface (the face that is in contact with the mould), the other face is ‘uncontrolled’ but is often inside, so doesn’t matter what it looks like.

Someone mentioned carbon tubes into steel lugs, fine, but isolate the carbon from the steel (galvanic corrosion).

Hmm.. the vacuum method requires me to source a pump of some kind.. which is a whole pre-project.

Hence why I’m explaining that you almost certainly don’t need one. My understanding is that the vast majority of kayaks are made without a vacuum pump (in general you pay a significant premium to get a vac bagged one).

How big is what you’re thinking of (or you could always tell us exactly what it is unless there’s IP involved – send me a message on FB and I’ll fill in a NDA for you if necessary!)? Various options for molds, if it’s small then you can use plasticene, or for something a bit bigger making a single composite mould using glass on your mockup for the good side (which is how kayaks are usually made). Then lay up on your mould (don’t forget mould release, though IME if you’re not that bothered about finish supermarket carrier bags work) and use sand and a weight to compress the other side.

They would match up correctly, since I’d cast them both at the same time with a form.

However.. it woudn’t work easily, because I’d need to layer the fibres over the top of each other in different places because it’s quite a 3d shape.

The inside of the curve is important. So what I might do is get a foam block, scoop the inside of it out andcheck fit onto the bike, thereby making a female mould. Then I can cast a male form and proceed layering the carbon onto that. I reckon I can get away without vacuum, at least for aprototype.

I’d tell you what I’m planning but it’s such a simple and obvious thing that I’m amazed no-one’s thought of it yet (or produced it) and someone might just start rattling them off and remove any chance I have of making even a small bit of cash from it.

If someone’s already a dab hand at the fabrication I might cut them in to save hassle 🙂

carbon bell? Don’t like the sound of that?

If someone has access to a vacuum former it might be easier to do plastic prototypes first, to get the shape right.

To be honest if a plastic one could be made stiff and rock-proof enough it’d be a hell of a lot easier to just knock them out for sale on a vacuum former.

As aracer said, you don’t need a vacuum pump. Depending on the shape, wrap it all (mould and carbon) in insulating tape, sticky side out. prick some holes in it with a pin, and if you wrap it tightly, excess glue will seep out of the holes.
Mould material depends on how many parts you want to make from it, as it may get damaged when you remove the part.

M – I have an idea for something that could be easily made but isn’t available – given your last comment I suspect we might be on the same lines. I’ll drop you a mail.

Ok, lets do business 🙂

Carbon f***in bell??? 😯

I take my offer back 😕

Am intrigued now. Are we allowed to speculate on this thread, or should I start a new one for that? 😈

It’s not a carbon bell!

It’s not a pimpy weight saving version of something else either. It’s something I’ve never seen on any bike.

You may speculate 🙂

It’s something I’ve never seen on any bike.

A carbon fish!

As aracer said, you don’t need a vacuum pump. Depending on the shape, wrap it all (mould and carbon) in insulating tape, sticky side out. prick some holes in it with a pin, and if you wrap it tightly, excess glue will seep out of the holes.

Heat-shrink tape to get it tight. Worked for me (although that was mending, not making)
http://www.andrewhowett.blogspot.co.uk/2012/01/mending-carbon-frame.html

Depending on the shape, wrap it all (mould and carbon) in insulating tape, sticky side out. prick some holes in it with a pin, and if you wrap it tightly, excess glue will seep out of the holes.

Shrink tape would also be an option – wrap it tight then heat with hair drier to shrink some more.

Doh, 2 late

Heat shrinkg.. nice idea!

What about burying it in sand then rocks on top?

cover it in rocks

Always good to be able to see it hasn’t moved before the glue cures.

Yeah.. plus there’d be voids in the sand so could still contain some air…

Speculate you say…hmmmmm…

It’s a carbon Hot Water Tap and I claim my £5

You need investors, go to Kickstarter Projects website, set it up, get donations, built it, sell it, make Gazzillions, sell patent to large Bike Corporate, go live in Middlesborough… 😉

Kickstarter wouldn’t be a bad idea for this.. but then again if I get the process right I can knock up half a dozen at a time in my garage for little money, so I could flog some to the denizens of STW and make a modest profit, enough for some new forks maybe 🙂

Some sort of mudguard

Boring suggestion.

It’s something I’ve never seen on any bike.

Some sort of mudguard

😀

Just realised I can test the principle of the item itself really easily. Will report back after my next offroad ride.