Mark Kelly wrote:My home made oven is large enough to fit a whole bike, roughly 1200 x 1000 x 300, it gets to 120 C quite adequately with a 2 kW heating element. I use a simple PID with a thermocouple sensor controlling the element via an SSR.
The calculation is power = surface area x temperature difference / insulation "R" value in m^2.K/W. With my oven, surface area is about 3.6 m^2, temperature difference gets to almost 120 so even with ordinary R 2.0 insulation I should only need approx 216 watts. Of course that's maintenance value with no leaks and zero thermal mass inside the oven. I installed a much larger element to get a reasonable ramp up time.
Oh, I didn't think about building an oven myself
I had a quick look at these lab ovens that size and they cost upwards of $2k. I'm no oven expert so how do you build it to make sure you don't burn the whole thing down? I could get some help from a mate who's an electrical engineer. ~200W sounds reasonable for a DIY oven. I also looked up the CTE for plaster vs Al vs Fe, and yeah it's good. It sits somewhere between the latter two
AUbicycles wrote:Clever idea using the Rapid Prototyping / 3D printing for generating a mould though probably inefficient, particularly with the suface (3D printing quality) that needs to be finished/polished for a high quality surface on the carbon frame. ...
Well you never know until you try! I watched a few youtube videos on plaster mould casting and "rubber plaster" mould castings. The finished parts (aluminium) looks acceptable, though clearly they needed some finishing touches. 3D printed parts should have excellent surface finish, so I just need to find a way to keep that tolerance on the moulds, preferably semi-reusable. Either way I think there would be some buffing on the final product. I'm thinking of using aluminium tubes cut in half for the outer casing and fill it with rubber plaster. The casing can be clamped to withstand the pressure of the air bladder inside.
ftssjk wrote:i am thinking something more similar to a custom frame builder would be better for you, instead of something like a big bike company, as others have mentioned, the market has been saturated in regards to 'off the rack' frame designs.
i think your best bet 'niche' wise is the custom geometry, frame building. maybe something similar to baum, but less expensive? not in titanium (you could maybe offer titanium later)
Why not both? I was going to do a PhD in carbon fibre-epoxy/titanium FML (fibre metal laminates) hybrid composites but I found something else
Anyhow I think that's an overkill for a bicycle as you're probably not going to encounter any bird strikes, though possibly this may save your bike if you crash it. Airbus' A380 skin uses aluminium/S2 Glass FML due to its impact resistance and stiffness over monolithic aluminium. The downside was that it was expensive and as you can see they went all carbon in their A350 as CF technology matures (in this rather conservative industry).
I think Baum is the general direction I want to head, and yes, of course less expensive. I think in order to achieve that you'd have to streamline a few things and can't go full blown customised bikes. I'm exploring all options, though.
anyway if you like my idea, send me a few peanuts please
Once (if) I have the whole thing thought out, I'm sure I can do a bit better than a few peanuts
human909 wrote:(My sister has been riding to work on a 40 year old bike. Essentially it does the job as well as modern alternatives. In fact better than most modern alternatives available in Australia. Unfortunately the seat tube broke this week. She is examining repair options to keep the old steed ticking along.)
That must be a really awesome bike
Hard to find something that still rolls at that kind of age.
george-bob wrote:I wonder if custom geometry carbon fibre bikes would be possible at a reasonable price. Design the joining parts of the frame (BB shell, head tube, seatpost insert and rear dropouts) have a bunch of them produced by a good chinese manfacuturer. ... If you could sell custom geometry carbon frames for under $2k you might be able to find a decent local market.
This wasn't the original model I had in mind, but I'll think about it as pretty much anything is on the table at this stage. At the moment these pretty frames from Specialized and Cervelo go for $5k+ and that's the area I intend to explore.
mitzikatzi wrote:I think it would be easier to make your money in some area other then bikes.
Yes of course! But it's not about the money
I won't proceed with it unless I have a solid plan.