Thanks to a friend who borrowed me a 3d Prusa i3 (it actually is Jelwek i3 which is a copy of Prusa) printer I was able to print the dome.
I used the models created by the BB-8 Builder’s Club (you can find them on facebook) but I had to scale it. I compared the size of the original 506mm body to my 300mm body and figured its 59% (with fractions but 3d Slicer application can scale only with integers).
And the results:
I only got problem with the base layers which are melting and I think there is too much filament extruded – maybe the height of the first layer is too low? I will need to check it out and print the “pie panel” again as it is unacceptable at the moment:
It is not only too much melted plastic but also the edge is curling up.
Now it time for some sanding and smoothing.
After that probably glueing the thing together (top and bottom part separately so I have better access to the dome to install the lights.
Also, when done with white parts I’ll print the lenses with black filament.
Having quite ready mechanisms (more info in upcoming note) I decided to start working on the appearance.
First thing to be done is to make the styrofoam balls more durable and smooth it looks nice and realistic when the paint is applied.
I decided to go with a putty/filler in spray. I bought 4 spray cans and tested on the spare dome:
And as you can see – IT SUCKS! I didn’t check before that the spray had acetone and basically melts the styrofoam so now it looks like face of Deadpool…
I could not get ANY primer for styrofoam or plastic but I found paint which is supposed to be applied directly on styrofoam – I though this could be used as primer but as you can see it made it even worse. Paint applied:
And putty applied:
This has destroyed my motivation for few days…
I finally came up with the idea that other people are using when creating the ball from scratch and paper. I cover the ball with paper strips:
And applied thin layer of the filler:
Finally it does not destroy the ball and is smooth.
Strips can be seen here but this was quite thick paper and thin putty layer. I hope that if I use thinner paper and apply few layers of the putty the strips should not be visible.
Also! I got really good and exciting news as my friend is willing to lend me a 3d printer so I’ll be able to get nice prints of the lenses
I cut a square hole in the base to insert the stick and attached rollers in front and back so the platform sits and rolls nicely:
This is how it fits inside the ball:
Then, I put the stick into the hole (higher than it should) and put the top of the body on pushing the stick with magnets to the level where it would touch the top of the ball. Then I would open it, push the stick ~4mm down and draw the line at the level where it should be attached to the base.
And eventually attach the stick with screws to the platform (yeah, one screw is missing):
In the end – looks quite fine and balanced:
You can see that the space for head-rotation engine is facing forward – I will counter the weight of that with the battery pack fitted on the other side of the stick close to the bottom of the base.
The extra stick under the base will be used as an attachment for a weight (probably a 0,75kg disc from a dumbbell).
As mentioned in the previous note, I had a lot of problems with the stability and balancing, and not even the head was attached! So I just gave up on that design and choose the one used more often by other people – wide base with wheels spread widely.
Construction in this way gives a lot of space under it to have extra weight attached and having the centre of mass situated lower.
There is really nothing special to mention – I just cut the wheel from plywood, cut the holes for wheels and attached them.
As the platform was big enough to fit the loose elements, I gave it a quick test-drive:
Turning in place works – I did not test going forward-backward as there are no rollers in front and back of this base yet, so I would not like the styrofoam to be scratched.
Head platform will be attached to the sphere using magnets (situated under the head and on small platform inside the ball body).
Tricky part was to have these magnets at the right height – too high and these would touch the top of the sphere, too low and the magnet attraction would be too low to keep the head in place.
So to have the right length I put the device inside and draw a line on the stick at the level of the body’s half:
Then I put it upside-down and tried to find how high the magnets should be situated. It seems that this block of styrofoam had the right height:
I started carving the platform for magnets and attaching screws which would be used to position the platform at the right place:
Unfortunately – the screws were too short. I changed it to the styrofoam block instead:
It was a little to high so I cut it – also, I made the holes for the screws so it is kept nicely in place.
Finally – the internal mechanism is fixed…
I do not have a video of this but when I turn it on, close the body and attach the magnets on the outside and move, and try moving – the insides just fall front or back – the top part of the mechanisms has become too heavy. There is no way that this is going to work with the head attached and the bottom base is so stuffed that there is no space for adding additional weight.
One of the cute things the real BB-8 is doing are the sounds.
To give voice to my version I bought cheap Chinese speaker, got an unused microSD card from a friend and loaded BB-8 sounds which were shared by BB-8 Builders Club
The sounds are AMAZING! Maybe I am biased as the creator but I think it sounds even better than in the movie!
I attached the speaker inside of the body – as long as it is just styrofoam it sounds ok, I am just a little bit worried that when I also cover it with putty and paint the sound may get stuck inside and never go out… In that case I will need to move the speaker to the head which will have an opening hole on the bottom and which will let the sound waves to flow freely.
As this was about to be the ending part of the “insides” I also glued the power switch to finally keep it in on place and put the power indicator light in place under the zip-tie so it doesn’t dangle anymore:
The only thing left is to attach the magnets on top and once the head is ready to be attached – work on the balancing and adding additional weight.
The next part was very tricky – I had to cut the round “skirt” out of styrofoam.
I simply cut the circle of the size of the head hemisphere.
Then I had to cut it at an angle – I checked in the 3d project (I used Sketchup and downloaded two BB-8 models from the Google repository) how wide should be the top and bottom of the skirt.
Then, using compass, I draw the smaller circle on the other side and started precision cutting with brand new, sharp paper knife. It took a lot of precision and time to make it but the final effect is very nice (of course – it is upside-down in the picture):
Then I cut holes for the roller balls:
BUT! I did not like it as the attachment was not precise and I did not have any good idea to keep these in place. Fortunately enough, I was inspired by another BB-8 Builders Club member to make a separate platform with roller which I figured to make from this old tray:
I cut small holes using driller and glued the rollers into place. I had a lot of luck at this point as these fit, roll nice and the distance to ball is perfect! No need to change it
Here you can see how nicely it fits, there is just a little space between the skirt and the body (again upside-down):
Eventually, when combined, body and head begins to remind the real shape of the BB-8:
Still, I will need to cut one more ring to put between the skirt and the hemisphere as in the movie it has that silver ring in that place.
This, however, should not be that difficult anymore.
Once I got the base running smooth I started creating the mechanism for the head rotation. Eventually, head will be spinning left/right – it would be awesome to have it also tilting to sides and front/back but for now it would be too difficult to manage.
So, I took the base of the rotating excavator platform…
…and cut off and trimmed the needed parts:
The mechanism is simple – the yellow part with the engine will be fixed on top of the core stick and the white cogweel will be rotating with a magnet platform attached to it just under the top of the body sphere.
The tricky part was to cut the wooden stick to the right length so I decided to make it shorter and then, if needed, put some distance to make the perfect spot for the magnets.
The only thing left for the internal mechasm is to attach the speaker for sounds and magnets on the rotating platform.
I knew I needed some roller balls for the “head platform” to slide nicely when the body moves so I ordered (as seen in some people’s solutions at BB-8 Builders Club) the following massage “hand”:
It is way cheaper than buying separate roller balls. After some cutting I separated them:
For the head platform I am going to need just 3-4 balls so I was left with 5-6 more. They are rolling so nice and smooth that I decided to replace the current “temporary spoon stabilization mechanism” with them.
All I had to do was to measure and cut the bases from thick styrofoam and attach the rollers:
Too bad I don’t have more pics but it was quite simple and quick. I just glued the rollers to white bases, then again checked if the distances were ok and then glued them to the core of the mechanism (between the engines and to the battery pack flap.