Yeti build thread. Not in the wrong section.

[LumPi Panda]

A peek behind the curtain. Apologies for low quality screen captures, these are the CAD drawings for the chainset. Layers of 1mm and 0.5mm acrylic, laser cut and stacked together.






Ends up looking like this. Not happy with the chainrings, need to be pointier...


That's better. I must have made about four or five chainsets before I was satisfied.

 

[LumPi Panda]

Handlebars. For something so simple these were one of the trickiest bits to get right. Getting the rise, sweep and taper symmetrical was a bit of a task.

 

[LumPi Panda]

Right.

Tyres.

This is going to take a while...


Three different thicknesses of plastic to build the basic profile. These five will do one one side.


Filler to round it out. Taking care not to get any the slots, we're going to need them later.


Glad that's over. Audiobooks came in useful here.

 

[LumPi Panda]

Peg goes into slot, tread goes onto peg.


Filler goes under tread. Filler gets sanded square.

More treads go on, mind goes a bit funny.

Feeling of relief, obliterated by crashing realisation that you have to do it all again for the other side...

 

[LumPi Panda]

Just got to clean up all the little imperfections, then it can be moulded and cast in resin.

 

[Lucidone]

Thank you - this is an amazing insight into both your skills and some model making techniques.

Appreciate this is retrospective but if there's any way you might be able to incorporate some of the tools, work holding and jigs you use I for one would be fascinated.

 

[LumPi Panda]

Who doesn't love a bit of dry assembly?



Retro style trispokes are just for trial assembly purposes.
The final ones are going to have spokes.

My god, what have I started?

 

[LumPi Panda]

Thank you - this is an amazing insight into both your skills and some model making techniques.

Appreciate this is respective but if there's any way you might be able to incorporate some of the tools, work holding and jigs you use I for one would be fascinated.

Thanks Lucidone,
Of course. Tools are fairly straightforward;


Hands. I have two of these, but one was holding the camera. It looks pretty similar to this one, but the other way around.


Scalpel - indispensable.
Tweezers - in a variety of shapes and sizes.
Accurate rule - useful for prising lids off paint.
Reverse action tweezers - extremely useful for holding small things while sticking other small things to them.
Brushes - also in a variety of shapes and sizes.
That's about it for hand tools apart from various grades of abrasive paper, usually double sided taped onto various shaped sticks.


CAD. How did anyone make anything before CAD?


Big frickin' lasers. Didn't need to be this big, but that's what we have at work. If I had a smaller one at home I would probably have already made a couple of other bikes by now.

I still have all of the jigs, moulds and patterns in the loft at home. I'll dig them out if you're interested.
Also, stay tuned for the wheel building bit later on. Some pretty bad-ass jigs in that bit.

 

[Lucidone]

Thanks and yes, interested to see whatever you'd like to share.
For final shaping/moulding is most of this done in material addition (filler material) rather than removal (scraping, filing, sanding etc.)?

 

[LumPi Panda]

Thanks and yes, interested to see whatever you'd like to share.
For final shaping/moulding is most of this done in material addition (filler material) rather than removal (scraping, filing, sanding etc.)?

A bit of both, but mainly addition with some type of filler.

For example this is the section through the tyre carcass:

The blue bits are 2mm thick acrylic rings, the red 1mm and the yellow 0.8mm. After the rings are stuck together, filler makes up the green outline. You then sand it back until the white edge of the acrylic starts to peek through.

With any filler work there is also reductive work to be done. You have to put too much filler on and then scrape/file/sand it back to where it needs to be. The green filler in the tyre treads took a lot of work with needle files to square them off.

There is always more than one lot of filler for any bit. First lot fleshes out the shape, subsequent ones fill gaps.

Fill.

Sand.

Repeat.

Don't get me started talking about different types of filler mind, I could probably fill the internet.