Building the frame - Part 2

Saturday 17 March

Made use of the jig again to cut the top plate - will use it again for the middle ring as well. I think I will also try to arrange the partial rings in one or more circles for cutting so I can do them all at one using the jig again.
I copied the detail from the full size Senna frame templates printout again using carbon paper.

Top and Bottom plates

Have also cut out all of the uprights today. The two main supports are completed but the rest of the uprights need to have their slots cut out - Will do this tomorrow as today is a beautiful day and I need to enjoy some it it with my family.

Very exciting moment - enough uprights to support the dome (have actually cut them all out but took this photo after the first few were done as I couldn't wait to see R2 take shape. 

Sunday 18 March

Had a false start today. I started using the circle slot jig to cut the slots in the uprights was was not aboe to hold them in place firmly while routing the slots. The spin of the router moved the ply to one side and resulted in diagonal slots. This cost me one of my uprights so I had to cut a new one. Also made up a jig specifically for this task out of some scraps - including the wasted upright.

Jig for cutting slots in uprights. The piece being cut is the longer horizontal piece in the foreground. The smaller horizontal piece is a stopper for the router. The vertical piece (the wasted upright) is the guide for the router.

Have now finished cutting the frame and everything lines up but I need to sand or file out some of the slots for a perfect fit. All in all - a good productive weekend..

All pieces cut and in place (not yet fixed in place)

Building the frame - Part 1

Sunday 11 March

I didn't plan on starting the frame this soon as I am still in the middle of plastering the dome. The weather is cold at the moment and the plaster seems to be taking forever to dry - I need something else to do so the frame seemed like a good option.

My frame will be made from plywood and based on the Senna frame templates. I say "based on" because I have to make some adjustments due to plywood here (in New Zealand) only being available in metric sizes.
The Senna frame is based on half and three-quarter inch ply. I will be using 17mm instead of three-quarter inch ply (19mm), and 12mm instead of half inch ply (12.7mm).

Base plate

I had two copies of the template printed full size - I will keep one copy for reference (and to admire); the other copy I have cut into pieces like sewing pattern - I will use this for marking up the plywood.

Base plate cut out (outline only). With template taped in place so I can mark the plywood  using carbon paper ready for for the routing. 

Here is the base plate with the carbon paper markings

I stopped here for a while because, while I was studying the frame templates, I was trying to decide how best to cut the slots. After sleeping on it I decided that I would make a jig for the router that will pivot about the centre of the plate and clamp to the outside of the plate, and allow me to quickly rotate around this, the top plate, and the rings, while cutting grooves and slots at just the correct length and angle (always towards the centre).

Monday 12 March

My jig for cutting the slots in base plate, top plate, and rings

Friday 16 March

Completed base plate

Have finally cut out the base plate. The jig worked really well but I had to move the pivot point 6mm as I had measured to the centre of the router and not the edge of the 12mm bit. Using the jig it only took a few minutes to cut out the slots and a couple of hours to do the rest without a jig.
Made a couple of mistakes (see repair at position 4 o'clock ) but the 10 slots are all OK.
Decided to cut the  four clearance hollows (as positions 12, 4, 6, and 10 o'clock) all the way through - according to specs (Senna frame prints by M Hendricks) the thickness of ply that needs to remain in these areas is between 0.02" and 0.03" (0.5mm and 0.75mm). I initially cut them like that but the remaining ply was so thin and fragile that a couple of them just fell apart as I was cutting them. I think this will be OK as the vacuum formed underbelly should cover this.

Building the dome - Welcome to the club

Saturday 3 March

I found good instructions for making a fibreglass dome at Astromech.net (The official site of the R2D2 builders club) but because of a serious lack of fibre glassing skills I thought I would experiment with a vacuum formed dome. I tried this a few weeks ago and the results seemed ok (on a half size dome) formed with PETG plastic over one half of a 240mm polystyrene dome from the craft store. I started on the full size dome using the same instructions (see above) as a guide for the plug.

Note: before starting any of this I have spent a lot of evenings over the last month googling for all of the information and images I could find relating to building a full size R2D2 and Astromech.net and it's related R2-D2 builders club have everything you need to know. I applied to join the group was was excited to receive a message the next day to say membership was approved - Welcome to the club. That was two weeks ago, and as suggested in my welcome letter I have been doing even more research since.
I am now at a point where I am comfortable enough to start with creating the dome.


The photos below illustrate the dome being made.

Cutting out a base for the dome from 12mm MDF on Saturday after having spent the morning making a circle jig for the router.

After cutting out base for dome. Note: As I will be vacuum forming the dome from 3mm  styrene, the  wall thickness of the dome will vary in thickness from 3mm at the top to (I expect) about 1mm at the base. I have reduced the diameter of the base by 2mm to allow for this as the dome plug that I am making be the size of the inside of the final dome so in this respect, it differs from the plug for the fibreglass dome in the instructions above.

Cutting out the first polystyrene layer to build up the dome. I forgot to mention that the dome will include the  blue and silver neck rings as well.

Fixing a block (using gorilla glue) to the base to hold the steel rod in place that will hold the dome former.

Trying out the former. I cut out the former according to the R2 builders club's dome profile drawing 

Start of the process of laminating the polystyrene slices to build up a rough dome. Fixing the first slice to teh base with gorilla glue and applying pressure with weights while the glue dries.

After all layers have been laminated and I have started carving and sanding them into shape to fit  within the former.

Polystyrene dome after initial shaping completed

Polystyrene dome after first layer of plaster.

Polystyrene dome after several layers of plaster - now the correct shape but still some has imperfections